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Keywords = UFG titanium

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33 pages, 93733 KiB  
Article
Corrosion Resistance of the Welded Joints from the Ultrafine-Grained Near-α Titanium Alloys Ti-5Al-2V Obtained by Spark Plasma Sintering
by Vladimir Chuvil’deev, Aleksey Nokhrin, Constantin Likhnitskii, Vladimir Kopylov, Pavel Andreev, Maksim Boldin, Nataliya Tabachkova and Aleksander Malkin
Metals 2023, 13(4), 766; https://doi.org/10.3390/met13040766 - 14 Apr 2023
Cited by 1 | Viewed by 1371
Abstract
A solid-phase diffusion welding of coarse-grained and ultrafine-grained (UFG) specimens of titanium near-α alloy Ti-5Al-2V used in nuclear power engineering was made by Spark Plasma Sintering. The failure of the welded specimens in the conditions of hot salt corrosion and electrochemical corrosion was [...] Read more.
A solid-phase diffusion welding of coarse-grained and ultrafine-grained (UFG) specimens of titanium near-α alloy Ti-5Al-2V used in nuclear power engineering was made by Spark Plasma Sintering. The failure of the welded specimens in the conditions of hot salt corrosion and electrochemical corrosion was shown to have a preferentially intercrystalline character. In the case of the presence of macrodefects, crevice corrosion of the welded joints was observed. The resistance of the alloys against the intercrystalline corrosion was found to be determined by the concentration of vanadium at the titanium grain boundaries, by the size and volume fraction of the β-phase particles, and by the presence of micro- and macropores in the welded joints. The specimens of the welded joints of the UFG alloy are harder and have a higher resistance to hot salt corrosion and electrochemical corrosion. Full article
(This article belongs to the Special Issue Advances in Titanium Alloys: Mechanical Properties, Microstructure and Ultrasonic Impact Treatment)
►▼ Show Figures

Figure 1

Figure 1
<p>Scheme of diffusion welding of the titanium alloy specimens by SPS (<b>a</b>). Photographs of coarse-grained specimens obtained at different diffusion welding temperatures (V<sub>h</sub> = 100 °C/min, P = 50 MPa, t = 10 min) (<b>b</b>) and the locations of different zones in the cross-sections of the investigated specimens (<b>c</b>). The “1” and “2” in subfigure (<b>b</b>) is specimen #1 and specimen #2 respectively.</p> Full article ">Figure 1 Cont.
<p>Scheme of diffusion welding of the titanium alloy specimens by SPS (<b>a</b>). Photographs of coarse-grained specimens obtained at different diffusion welding temperatures (V<sub>h</sub> = 100 °C/min, P = 50 MPa, t = 10 min) (<b>b</b>) and the locations of different zones in the cross-sections of the investigated specimens (<b>c</b>). The “1” and “2” in subfigure (<b>b</b>) is specimen #1 and specimen #2 respectively.</p> Full article ">Figure 2
<p>Position of the corrosion area relative to the welded joint. Specimen of the coarse-grained alloy (V<sub>h</sub> = 10 °C/min, T = 700 °C, t = 10 min, P = 50 MPa) after the electrochemical testing. The joint line is marked by yellow arrows. The corrosion area of 0.3 × 0.2 mm<sup>2</sup> in size has darker borders. SEM.</p> Full article ">Figure 3
<p>Microstructure in the coarse-grained (<b>a</b>,<b>b</b>) and UFG (<b>c</b>,<b>d</b>) alloy Ti-5Al-2V, reprinted with permission from [<a href="#B26-metals-13-00766" class="html-bibr">26</a>,<a href="#B50-metals-13-00766" class="html-bibr">50</a>]: (<b>a</b>) metallography; (<b>b</b>) SEM; (<b>c</b>,<b>d</b>) TEM.</p> Full article ">Figure 3 Cont.
<p>Microstructure in the coarse-grained (<b>a</b>,<b>b</b>) and UFG (<b>c</b>,<b>d</b>) alloy Ti-5Al-2V, reprinted with permission from [<a href="#B26-metals-13-00766" class="html-bibr">26</a>,<a href="#B50-metals-13-00766" class="html-bibr">50</a>]: (<b>a</b>) metallography; (<b>b</b>) SEM; (<b>c</b>,<b>d</b>) TEM.</p> Full article ">Figure 4
<p>EDS microanalysis of the grain boundary composition in the coarse-grained (<b>a</b>–<b>c</b>) and UFG (<b>d</b>) alloy Ti-5Al-2V, reprinted with permission from [<a href="#B26-metals-13-00766" class="html-bibr">26</a>,<a href="#B50-metals-13-00766" class="html-bibr">50</a>]. (<b>a</b>) GB of type I; (<b>b</b>) GB of type II; (<b>c</b>) β-particle in the GB of type II; (<b>d</b>) GB in the UFG alloy. TEM.</p> Full article ">Figure 4 Cont.
<p>EDS microanalysis of the grain boundary composition in the coarse-grained (<b>a</b>–<b>c</b>) and UFG (<b>d</b>) alloy Ti-5Al-2V, reprinted with permission from [<a href="#B26-metals-13-00766" class="html-bibr">26</a>,<a href="#B50-metals-13-00766" class="html-bibr">50</a>]. (<b>a</b>) GB of type I; (<b>b</b>) GB of type II; (<b>c</b>) β-particle in the GB of type II; (<b>d</b>) GB in the UFG alloy. TEM.</p> Full article ">Figure 5
<p>Photographs of the alloy specimens after HSC testing (<b>a</b>,<b>b</b>), after rinsing in a hot water flow (<b>c</b>), and after mechanical polishing (<b>d</b>,<b>e</b>). In (<b>d</b>), the largest corrosion pits are highlighted by a yellow dashed line. The white solid line outlines a joint macrodefect, which the crevice corrosion and the pitting one go through simultaneously. In (<b>e</b>), the welded joint area (Zone I, see <a href="#metals-13-00766-f001" class="html-fig">Figure 1</a>c) is outlined by a white dashed line.</p> Full article ">Figure 5 Cont.
<p>Photographs of the alloy specimens after HSC testing (<b>a</b>,<b>b</b>), after rinsing in a hot water flow (<b>c</b>), and after mechanical polishing (<b>d</b>,<b>e</b>). In (<b>d</b>), the largest corrosion pits are highlighted by a yellow dashed line. The white solid line outlines a joint macrodefect, which the crevice corrosion and the pitting one go through simultaneously. In (<b>e</b>), the welded joint area (Zone I, see <a href="#metals-13-00766-f001" class="html-fig">Figure 1</a>c) is outlined by a white dashed line.</p> Full article ">Figure 6
<p>Typical defects in the welded joints of the coarse-grained (<b>a</b>,<b>c</b>,<b>e</b>) and UFG (<b>b</b>,<b>d</b>,<b>f</b>) alloy after the diffusion welding (V<sub>h</sub> = 50 °C/min, T = 800 °C, t = 10 min): (<b>a</b>,<b>b</b>) a joint defect, (<b>c</b>,<b>d</b>) a macropore, (<b>e</b>,<b>f</b>) a micropore. SEM.</p> Full article ">Figure 6 Cont.
<p>Typical defects in the welded joints of the coarse-grained (<b>a</b>,<b>c</b>,<b>e</b>) and UFG (<b>b</b>,<b>d</b>,<b>f</b>) alloy after the diffusion welding (V<sub>h</sub> = 50 °C/min, T = 800 °C, t = 10 min): (<b>a</b>,<b>b</b>) a joint defect, (<b>c</b>,<b>d</b>) a macropore, (<b>e</b>,<b>f</b>) a micropore. SEM.</p> Full article ">Figure 7
<p>Micropores in the welded joints of the UFG titanium alloy after diffusion welding (t = 10 min, P = 50 MPa): (<b>a</b>) V<sub>h</sub> = 50 °C/min, T = 600 °C; (<b>b</b>) V<sub>h</sub> = 350 °C/min, T = 700 °C; (<b>c</b>) V<sub>h</sub> = 50 °C/min, T = 800 °C. SEM.</p> Full article ">Figure 7 Cont.
<p>Micropores in the welded joints of the UFG titanium alloy after diffusion welding (t = 10 min, P = 50 MPa): (<b>a</b>) V<sub>h</sub> = 50 °C/min, T = 600 °C; (<b>b</b>) V<sub>h</sub> = 350 °C/min, T = 700 °C; (<b>c</b>) V<sub>h</sub> = 50 °C/min, T = 800 °C. SEM.</p> Full article ">Figure 8
<p>Microstructure of the specimens of the coarse-grained alloy obtained in different regimes of the diffusion welding (P = 50 MPa, t = 10 min): (<b>a</b>) V<sub>h</sub> = 50 °C/min, T = 600 °C; (<b>b</b>) V<sub>h</sub> = 50 °C/min, T = 800 °C; (<b>c</b>) V<sub>h</sub> = 100 °C/min, T = 700 °C; (<b>d</b>) V<sub>h</sub> = 350 °C/min, T = 700 °C. SEM.</p> Full article ">Figure 8 Cont.
<p>Microstructure of the specimens of the coarse-grained alloy obtained in different regimes of the diffusion welding (P = 50 MPa, t = 10 min): (<b>a</b>) V<sub>h</sub> = 50 °C/min, T = 600 °C; (<b>b</b>) V<sub>h</sub> = 50 °C/min, T = 800 °C; (<b>c</b>) V<sub>h</sub> = 100 °C/min, T = 700 °C; (<b>d</b>) V<sub>h</sub> = 350 °C/min, T = 700 °C. SEM.</p> Full article ">Figure 9
<p>Microstructure of the UFG specimens obtained in different diffusion welding regimes (P = 50 MPa): (<b>a</b>) V<sub>h</sub> = 50 °C/min, T = 600 °C, t = 10 min; (<b>b</b>) V<sub>h</sub> = 50 °C/min, T = 700 °C, t = 10 min; (<b>c</b>) V<sub>h</sub> = 50 °C/min, T = 800 °C, t = 10 min; (<b>d</b>) V<sub>h</sub> = 100 °C/min, T = 700 °C, t = 10 min; (<b>e</b>) V<sub>h</sub> = 350 °C/min, T = 700 °C, t = 10 min; (<b>f</b>) V<sub>h</sub> = 50 °C/min, T = 700 °C, t = 90 min. SEM.</p> Full article ">Figure 9 Cont.
<p>Microstructure of the UFG specimens obtained in different diffusion welding regimes (P = 50 MPa): (<b>a</b>) V<sub>h</sub> = 50 °C/min, T = 600 °C, t = 10 min; (<b>b</b>) V<sub>h</sub> = 50 °C/min, T = 700 °C, t = 10 min; (<b>c</b>) V<sub>h</sub> = 50 °C/min, T = 800 °C, t = 10 min; (<b>d</b>) V<sub>h</sub> = 100 °C/min, T = 700 °C, t = 10 min; (<b>e</b>) V<sub>h</sub> = 350 °C/min, T = 700 °C, t = 10 min; (<b>f</b>) V<sub>h</sub> = 50 °C/min, T = 700 °C, t = 90 min. SEM.</p> Full article ">Figure 10
<p>Results of XRD analysis of the corrosion products on the surfaces of the specimens of coarse-grained (<b>a</b>) and UFG (<b>b</b>) alloys after HSC testing. The numbers (1) and (2) in (<b>a</b>,<b>b</b>) correspond to samples #1 and #2 (see <a href="#metals-13-00766-f001" class="html-fig">Figure 1</a>b,c).</p> Full article ">Figure 11
<p>Results of XRD analysis of the salt contaminations on the surfaces of coarse-grained (<b>a</b>,<b>b</b>) and UFG (<b>c</b>,<b>d</b>) specimens after HSC testing: (<b>a</b>,<b>c</b>) V<sub>h</sub> = 50 °C/min, T = 600 °C, t = 10 min, P = 50 MPa; (<b>b</b>) V<sub>h</sub> = 50 °C/min, T = 1030 °C, t = 10 min, P = 50 MPa; (<b>d</b>) V<sub>h</sub> = 50 °C/min, T = 1140 °C, t = 10 min, P = 50 MPa.</p> Full article ">Figure 11 Cont.
<p>Results of XRD analysis of the salt contaminations on the surfaces of coarse-grained (<b>a</b>,<b>b</b>) and UFG (<b>c</b>,<b>d</b>) specimens after HSC testing: (<b>a</b>,<b>c</b>) V<sub>h</sub> = 50 °C/min, T = 600 °C, t = 10 min, P = 50 MPa; (<b>b</b>) V<sub>h</sub> = 50 °C/min, T = 1030 °C, t = 10 min, P = 50 MPa; (<b>d</b>) V<sub>h</sub> = 50 °C/min, T = 1140 °C, t = 10 min, P = 50 MPa.</p> Full article ">Figure 12
<p>Corrosion defects on the surfaces of the coarse-grained specimens after HSC testing: (<b>a</b>,<b>b</b>) crevice corrosion in Zone I; (<b>c</b>,<b>d</b>) pitting corrosion in Zone II, (<b>e</b>) IGC in Zone II. Zones I and II are denoted in accordance with <a href="#metals-13-00766-f001" class="html-fig">Figure 1</a>c. Metallography.</p> Full article ">Figure 12 Cont.
<p>Corrosion defects on the surfaces of the coarse-grained specimens after HSC testing: (<b>a</b>,<b>b</b>) crevice corrosion in Zone I; (<b>c</b>,<b>d</b>) pitting corrosion in Zone II, (<b>e</b>) IGC in Zone II. Zones I and II are denoted in accordance with <a href="#metals-13-00766-f001" class="html-fig">Figure 1</a>c. Metallography.</p> Full article ">Figure 13
<p>Nonuniformity of the metal microstructure in the weld joint area of the coarse-grained titanium alloy: (<b>a</b>) SEM; (<b>b</b>) Metallography.</p> Full article ">Figure 14
<p>The nonuniform distribution of large corrosion pits at different sides of the joint line of the coarse-grained alloy after HSC testing: (<b>a</b>) V<sub>h</sub> = 100 °C/min, t = 700 °C, t = 10 min, P = 50 MPa; (<b>b</b>) V<sub>h</sub> = 100 °C/min, t = 700 °C, t = 10 min, P = 100 MPa. Examples of defect formation in the plate-wise α-phase regions are presented in (<b>c</b>,<b>d</b>). Metallography.</p> Full article ">Figure 15
<p>Corrosion defects on the surface of the UFG specimens after HSC testing: (<b>a</b>) V<sub>h</sub> = 100 °C/min, T = 700 °C, t = 0 min, P = 50 MPa, (<b>b</b>) V<sub>h</sub> = 100 °C/min, T = 600 °C, t = 10 min, P = 50 MPa, (<b>c</b>) V<sub>h</sub> = 100 °C/min, t = 800 °C, t = 10 min, P = 50 MPa, (<b>d</b>) V<sub>h</sub> = 100 °C/min, t = 700 °C, t = 10 min, P = 50 MPa. Metallography.</p> Full article ">Figure 16
<p>Results of the electrochemical investigations of the coarse-grained (red line) and UFG (black line) specimens: Tafel curves for the (<b>a</b>) SPS temperature (circles (line #1)—600 °C, rhombus (#2)—700 °C, squares (#3)—800 °C, triangles (#4)—1030 °C for the coarse-grained alloys; 1140 °C for the UFG alloy); (<b>b</b>) heating rate (circles (#1)—10 °C/min, rhombus (#2)—50 °C/min, squares (#3)—100 °C/min, triangles (#4)—350 °C).</p> Full article ">Figure 17
<p>Surfaces of the coarse-grained (<b>a</b>) and UFG (<b>b</b>) specimens of the titanium alloy (V<sub>h</sub> = 100 °C/min, T = 600 °C, t = 10 min, P = 50 MPa) after the electrochemical testing. SEM.</p> Full article ">
14 pages, 9855 KiB  
Article
Effect of Heat Treatment on Microstructure and Mechanical Behavior of Ultrafine-Grained Ti-2Fe-0.1B
by Yaoyao Mi, Yanhuai Wang, Yu Wang, Yuecheng Dong, Hui Chang and I. V. Alexandrov
Materials 2023, 16(8), 2955; https://doi.org/10.3390/ma16082955 - 7 Apr 2023
Cited by 5 | Viewed by 1341
Abstract
In the present study, a novel Ti-2Fe-0.1B alloy was processed using equal channel angular pressing (ECAP) via route Bc for four passes. The isochronal annealing of the ultrafine-grained (UFG) Ti-2Fe-0.1B alloy was conducted at various temperatures between 150 and 750 °C with holding [...] Read more.
In the present study, a novel Ti-2Fe-0.1B alloy was processed using equal channel angular pressing (ECAP) via route Bc for four passes. The isochronal annealing of the ultrafine-grained (UFG) Ti-2Fe-0.1B alloy was conducted at various temperatures between 150 and 750 °C with holding times of 60 min. The isothermal annealing was performed at 350–750 °C with different holding times (15 min–150 min). The results indicated that no obvious changes in the microhardness of the UFG Ti-2Fe-0.1B alloy are observed when the annealing temperature (AT) is up to 450 °C. Compared to the UFG state, it was found that excellent strength (~768 MPa) and ductility (~16%) matching can be achieved for the UFG Ti-2Fe-0.1B alloy when annealed at 450 °C. The microstructure of the UFG Ti-2Fe-0.1B alloy before and after the various annealing treatments was characterized using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). It was found that the average grain size remained at an ultrafine level (0.91–1.03 μm) when the annealing temperature was below 450 °C. The good thermal stability of the UFG Ti-2Fe-0.1B alloy could be ascribed to the pinning of the TiB needles and the segregation of the Fe solute atoms at the grain boundaries, which is of benefit for decreasing grain boundary energy and inhibiting the mobility of grain boundaries. For the UFG Ti-2Fe-0.1B alloy, a recrystallization activation energy with an average value of ~259.44 KJ/mol was analyzed using a differential scanning calorimeter (DSC). This is much higher than the lattice self-diffusion activation energy of pure titanium. Full article
(This article belongs to the Special Issue Advanced Metal Forming Processes II)
►▼ Show Figures

Figure 1

Figure 1
<p>Schematic illustration of (<b>a</b>) the processing routes and (<b>b</b>) sample-selected plane for tests.</p> Full article ">Figure 2
<p>Microstructure characteristics of the UFG TiFeB alloy: (<b>a</b>) inverse pole figures (IPF) map; (<b>b</b>) recrystallization map; (<b>c</b>,<b>d</b>) maps of grain boundaries and the misorientation angle distributions.</p> Full article ">Figure 3
<p>Microhardness development of the UFG TiFeB alloy: (<b>a</b>) isochronal annealing; (<b>b</b>) isothermal annealing.</p> Full article ">Figure 4
<p>Engineering stress–strain curves of the UFG TiFeB alloy after isochronal annealing at different temperatures.</p> Full article ">Figure 5
<p>IPF maps and the variation of grain sizes in the UFG TiFeB alloy after annealing at (<b>a</b>) 350 °C, (<b>b</b>) 400 °C, (<b>c</b>) 450 °C, (<b>d</b>) 550 °C, and (<b>e</b>) 650 °C for 1 h. (<b>f</b>) The relationship of grain sizes vs. annealing temperatures.</p> Full article ">Figure 6
<p>Misorientation angle distributions of the UFG TiFeB alloy after annealing for 1 h at different annealing temperatures of (<b>a</b>) 350 °C, (<b>b</b>) 400 °C, (<b>c</b>) 450 °C, (<b>d</b>) 550 °C, and (<b>e</b>) 650 °C. (<b>f</b>) The curve of HAGB variation with annealing temperature.</p> Full article ">Figure 7
<p>Recrystallization maps of the UFG TiFeB alloy after annealing for 1 h at different annealing temperatures of (<b>a</b>) 350 °C, (<b>b</b>) 400 °C, (<b>c</b>) 450 °C, (<b>d</b>) 550 °C, and (<b>e</b>) 650 °C. (<b>f</b>) The variation curve of the volume fraction with annealing temperature.</p> Full article ">Figure 8
<p>TEM micrographs of (<b>a</b>,<b>b</b>) the UFG TiFeB alloy samples, and the samples annealed at (<b>c</b>,<b>d</b>) 450 °C and (<b>e</b>,<b>f</b>) 650 °C.</p> Full article ">Figure 9
<p>TEM images and SAED pattern of the TiB phase within the TiFeB alloy annealed at 450 °C for 1 h. (<b>a</b>) TEM images of the TiB phase; (<b>b</b>) SAED pattern of the circled TiB phase.</p> Full article ">Figure 10
<p>EDS spot measurements showing the chemical compositions of (<b>a</b>) the UFG alloy and (<b>b</b>) the alloy annealed at 450 °C for 1 h.</p> Full article ">Figure 11
<p>Recrystallization activation energy of the UFG TiFeB alloy determined by DSC.</p> Full article ">
11 pages, 6663 KiB  
Article
Superplastic Behavior and Microstructural Features of the VT6 Titanium Alloy with an Ultrafine-Grained Structure during Upsetting
by Grigory S. Dyakonov, Andrey G. Stotskiy, Iuliia M. Modina and Irina P. Semenova
Materials 2023, 16(4), 1439; https://doi.org/10.3390/ma16041439 - 8 Feb 2023
Cited by 6 | Viewed by 1418
Abstract
In this paper, the superplastic behavior of the two-phase titanium alloy VT6 with an ultrafine-grained (UFG) structure produced by equal-channel angular pressing is examined. The deformation of specimens with a UFG structure was performed by upsetting in a temperature range of 650–750 °C [...] Read more.
In this paper, the superplastic behavior of the two-phase titanium alloy VT6 with an ultrafine-grained (UFG) structure produced by equal-channel angular pressing is examined. The deformation of specimens with a UFG structure was performed by upsetting in a temperature range of 650–750 °C and strain rate range of 1 × 10−4–5 × 10−1 s−1. Under these conditions, an increased strain-rate sensitivity coefficient m was observed. The calculation of apparent activation energy showed values in a range of 160–200 kJ/mol while the superplastic flow of the VT6 alloy was occurring. When superplastic behavior (SPB) was impeded, the energy Q grew considerably, indicating a change in mechanism from grain-boundary sliding (GBS) to bulk diffusion. A change in temperature and strain rate influenced the development of superplastic flow and the balance of relaxation processes. Microstructural analysis shows that the UFG state is preserved at upsetting temperatures of 650 and 700 °C. A decrease in strain rate and/or an increase in upsetting temperature promoted a more active development of recrystallization and grain growth, as well as α2-phase formation. In a certain temperature and strain-rate range of the UFG VT6 alloy, α2-phase plates were found, the formation of which was controlled by diffusion. The effect of the α2-phase on the alloy’s mechanical behavior is discussed. Full article
(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)
►▼ Show Figures

Figure 1

Figure 1
<p>Microstructure of the VT6 alloy after HT (<b>a</b>) and after ECAP (<b>b</b>).</p> Full article ">Figure 2
<p>True stress–true strain curves after upset at temperatures of 650 °C (<b>a</b>), 700 °C (<b>b</b>), 750 °C (<b>c</b>), the strain-rate sensitivity coefficient m (<b>d</b>).</p> Full article ">Figure 3
<p>Microstructure of the VT6 alloy after ECAP (<b>a</b>,<b>b</b>) and after additional upset with a strain rate of 1 <span class="html-italic">×</span> 10<sup>−3</sup> s<sup>−1</sup> at the following temperatures: (<b>c</b>) 650 °C, (<b>d</b>,<b>e</b>) 700 °C, (<b>f</b>) 750 °C (SE and BSE detectors).</p> Full article ">Figure 3 Cont.
<p>Microstructure of the VT6 alloy after ECAP (<b>a</b>,<b>b</b>) and after additional upset with a strain rate of 1 <span class="html-italic">×</span> 10<sup>−3</sup> s<sup>−1</sup> at the following temperatures: (<b>c</b>) 650 °C, (<b>d</b>,<b>e</b>) 700 °C, (<b>f</b>) 750 °C (SE and BSE detectors).</p> Full article ">Figure 4
<p>Microstructure of the VT6 alloy after ECAP (<b>a</b>) and after upset with a strain rate of 5 <span class="html-italic">×</span> 10<sup>−4</sup> s<sup>−1</sup> at a temperature of 650 °C (<b>b</b>).</p> Full article ">Figure 5
<p>Variation in the mean grain size of the UFG VT6 alloy after upset, depending on temperature and strain rate.</p> Full article ">Figure 6
<p>Microstructure of the VT6 alloy after upset at a temperature of 700 °C with strain rates of 1 <span class="html-italic">×</span> 10<sup>−3</sup> s<sup>−1</sup> (<b>a</b>), 5 <span class="html-italic">×</span> 10<sup>−4</sup> s<sup>−1</sup> (<b>b</b>,<b>c</b>), diffraction from a plate and a grain (<b>d</b>), and with a strain rate of 1 <span class="html-italic">×</span> 10<sup>−4</sup> s<sup>−1</sup> (<b>e</b>,<b>f</b>).</p> Full article ">Figure 6 Cont.
<p>Microstructure of the VT6 alloy after upset at a temperature of 700 °C with strain rates of 1 <span class="html-italic">×</span> 10<sup>−3</sup> s<sup>−1</sup> (<b>a</b>), 5 <span class="html-italic">×</span> 10<sup>−4</sup> s<sup>−1</sup> (<b>b</b>,<b>c</b>), diffraction from a plate and a grain (<b>d</b>), and with a strain rate of 1 <span class="html-italic">×</span> 10<sup>−4</sup> s<sup>−1</sup> (<b>e</b>,<b>f</b>).</p> Full article ">Figure 7
<p>Microstructure of the VT6 alloy after upset at a temperature of 750 °C with a strain rate of 1 <span class="html-italic">×</span> 10<sup>−3</sup> s<sup>−1</sup> (<b>a</b>), diffraction from a plate and a grain (<b>b</b>).</p> Full article ">Figure 8
<p>Schematic presentation of the processes occurring during upset, depending on temperature and strain rate.</p> Full article ">Figure 9
<p>Plot of lnσ vs. 1/T (<b>a</b>) and the calculated values of apparent activation energy at the upsetting temperatures (<b>b</b>).</p> Full article ">
13 pages, 6146 KiB  
Article
Thermal Stability and Mechanical Behavior of Ultrafine-Grained Titanium with Different Impurity Content
by Kamil Majchrowicz, Agata Sotniczuk, Joanna Malicka, Emilia Choińska and Halina Garbacz
Materials 2023, 16(4), 1339; https://doi.org/10.3390/ma16041339 - 4 Feb 2023
Cited by 7 | Viewed by 2029
Abstract
Ultrafine-grained (UFG) commercially pure (Ti Grade 2) and high-purity (Ti 99.99%) titanium can be a good alternative to less biocompatible Ti alloys in many biomedical applications. Their severe plastic deformation may lead to a substantial increase of strength, but their highly refined microstructure [...] Read more.
Ultrafine-grained (UFG) commercially pure (Ti Grade 2) and high-purity (Ti 99.99%) titanium can be a good alternative to less biocompatible Ti alloys in many biomedical applications. Their severe plastic deformation may lead to a substantial increase of strength, but their highly refined microstructure show a lower thermal stability which may limit their range of applications. The purpose of this study was to investigate the effect of interstitial elements on the thermal stability of UFG Ti Grade 2 and high-purity Ti 99.99% processed by a multi-pass cold rolling to the total thickness reduction of 90%. The severely cold rolled Ti sheets were annealed at temperature in the range of 100–600 °C for 1 h and, subsequently, they were evaluated in terms of microstructure stability, mechanical performance as well as heat effects measured by differential scanning calorimetry (DSC). It was found that the microstructure and mechanical properties were relatively stable up to 200 and 400 °C in the case of UFG Ti 99.99% and Ti Grade 2, respectively. DSC measurements confirmed the aforementioned results about lower temperature of recovery and recrystallization processes in the high-purity titanium. Surprisingly, the discontinuous yielding phenomenon occurred in both investigated materials after annealing above their thermal stability range, which was further discussed based on their microstructural characteristics. Additionally, the so-called hardening by annealing effect was observed within their thermal stability range (i.e., at 100–400 °C for UFG Ti Grade 2 and 100 °C for UFG Ti 99.99%). Full article
(This article belongs to the Special Issue Mechanical Performance and Microstructural Characterization of Light Alloys)
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<p>Microstructure of the as-rolled sheets: (<b>a</b>,<b>b</b>) Ti 99.99% and (<b>d</b>,<b>e</b>) Ti Grade 2 with the corresponding grain size distributions (<b>c</b>,<b>f</b>).</p> Full article ">Figure 2
<p>The variation of Vickers microhardness for Ti 99.99% and Ti Grade 2 after annealing at 100–600 °C.</p> Full article ">Figure 3
<p>Microstructure of the annealed sheets: (<b>a</b>,<b>b</b>) Ti 99.99% at 200 °C and (<b>d</b>,<b>e</b>) Ti Grade 2 at 400 °C with the corresponding grain size distributions (<b>c</b>,<b>f</b>).</p> Full article ">Figure 4
<p>Microstructure of the annealed sheets: (<b>a</b>,<b>b</b>) Ti 99.99% at 400 °C and (<b>d</b>,<b>e</b>) Ti Grade 2 at 500 °C with the corresponding grain size distributions (<b>c</b>,<b>f</b>).</p> Full article ">Figure 5
<p>Stress–strain curves and strain-hardening rate Θ versus true strain for (<b>a</b>,<b>b</b>) Ti 99.99% and (<b>c</b>,<b>d</b>) Ti Grade 2.</p> Full article ">Figure 6
<p>DSC curves representing heat flow as a function of annealing temperature for Ti 99.99% and Ti Grade 2.</p> Full article ">
11 pages, 9306 KiB  
Article
Effect of the Texture of the Ultrafine-Grained Ti-6Al-4V Titanium Alloy on Impact Toughness
by Iuliia M. Modina, Grigory S. Dyakonov, Andrey G. Stotskiy, Tatyana V. Yakovleva and Irina P. Semenova
Materials 2023, 16(3), 1318; https://doi.org/10.3390/ma16031318 - 3 Feb 2023
Cited by 9 | Viewed by 1805
Abstract
In this work, the strength properties and impact toughness of the ultrafine-grained (UFG) Ti-6Al-4V titanium alloy produced by severe plastic deformation (SPD) in combination with upsetting were studied, depending on the direction of crack propagation. In the billets processed by equal-channel angular pressing [...] Read more.
In this work, the strength properties and impact toughness of the ultrafine-grained (UFG) Ti-6Al-4V titanium alloy produced by severe plastic deformation (SPD) in combination with upsetting were studied, depending on the direction of crack propagation. In the billets processed by equal-channel angular pressing (ECAP), the presence of anisotropy of ultimate tensile strength (UTS) and ductility was observed, conditioned by the formation of a metallographic and crystallographic texture. At the same time, the ECAP-processed UFG alloy exhibited satisfactory values of impact toughness, ~0.42 MJ/m2. An additional upsetting of the ECAP-processed billet simulated the processes of shape forming/die forging and was accompanied by the development of recovery and recrystallization. This provided the “blurring” of texture and a reduction in the anisotropy of UTS and ductility, but a difference in impact toughness in several directions of fracture was still observed. It is shown that texture evolution during upsetting provided a significant increase in the crack propagation energy. The relationship between microstructure, texture and mechanical properties in different sections of the material under study is discussed. Full article
(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)
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<p>Equal-channel angular pressing: (<b>a</b>) microstructure of the billet; (<b>b</b>) principle of ECAP.</p> Full article ">Figure 2
<p>Schematic view of the Ti-6Al-4V titanium alloy samples after: (<b>a</b>) ECAP; (<b>b</b>) ECAP + upsetting, for microstructural studies, tensile mechanical tests and impact toughness tests with a V-notch.</p> Full article ">Figure 3
<p>Microstructure of the Ti-6Al-4V titanium alloy: (<b>a</b>) ultrafine-grained (UFG) state after ECAP; (<b>b</b>) UFG state after ECAP + upsetting.</p> Full article ">Figure 4
<p>(0001), {11.0} and {10.0} DPFs of the α-phase in the XZ-section for (<b>a</b>) the ECAP-processed billet and (<b>b</b>) the ECAP-processed billet after upsetting along the Z direction. Outer directions are indicated near the DPFs.</p> Full article ">Figure 5
<p>Typical curves from the tensile mechanical tests of the Ti-6Al-4V titanium alloy.</p> Full article ">Figure 6
<p>Schematic view showing the position of the crystallites of the hcp α-phase in the UFG structure of the Ti-6Al-4V titanium alloy after: (<b>a</b>) ECAP; (<b>b</b>) ECAP + upsetting.</p> Full article ">
10 pages, 3315 KiB  
Article
Deformation Behavior under Tension with Pulse Current of Ultrafine-Grain and Coarse-Grain CP Titanium
by Vladimir Stolyarov, Oleg Korolkov, Alexander Pesin and George Raab
Materials 2023, 16(1), 191; https://doi.org/10.3390/ma16010191 - 25 Dec 2022
Cited by 6 | Viewed by 1697
Abstract
The problem of the real existence of the electroplastic effect during deformation of metallic materials of different nature is still relevant. At the same time, the influence of structure refinement is not considered enough. In this work, the deformation behavior of ultrafine-grained (UFG) [...] Read more.
The problem of the real existence of the electroplastic effect during deformation of metallic materials of different nature is still relevant. At the same time, the influence of structure refinement is not considered enough. In this work, the deformation behavior of ultrafine-grained (UFG) titanium Grade 4 is compared with that of coarse-grained (CG) titanium under tension with pulse current of the low duty cycle. The deformation curves of both structure states are presented for different regimes of pulsed current and thermal heating from an external source. Structure studies by optical and scanning electron microscopy, as well as microhardness measurements have been carried out. It is shown that Grade 4 titanium under tension accompanied by pulsed current exhibits electroplastic effect (EPE) in the form of a flow stress reduction. EPE in UFG state is much stronger than in CG state. An increase in the density and duration of the current pulse leads to a multiple decrease in the flow stresses in CG and UFG titanium. The contribution in the flow stress reduction from heating by an external source was less than that from tension with pulse current at the same temperatures. The impact of pulsed current during tension does not influence microhardness and grain size. Full article
(This article belongs to the Special Issue Recent Advances on Mechanical Properties and Microstructural Features of Alloy/Steel)
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<p>Microstructure of titanium in CG (<b>a</b>) and UFG (<b>b</b>,<b>c</b>) states: (<b>a</b>)—along; (<b>b</b>)—cross section; (<b>c</b>)—longitudinal section.</p> Full article ">Figure 2
<p>Shape and dimensions of tensile specimens.</p> Full article ">Figure 3
<p>Diagram of the test setup: 1—pulse current generator; 2—oscilloscope; 3—captures; 4—thermocouple; 5—isolation; 6—sample.</p> Full article ">Figure 4
<p>Scheme of places for measuring microhardness and studying microstructure: 1—neck; 2—deformable zone; 3—non-deformable zone.</p> Full article ">Figure 5
<p>Microstructure of CG titanium tested with current (60 A/mm<sup>2</sup>, 500 μs, 200 °C): (<b>a</b>)—undeformed zone; (<b>b</b>)—deformed zone; (<b>c</b>)—neck.</p> Full article ">Figure 6
<p>Microstructure of CG titanium tested by heating with a dryer, 200 °C: (<b>a</b>)—undeformed zone; (<b>b</b>)—deformed zone; (<b>c</b>)—neck.</p> Full article ">Figure 7
<p>Changes in microhardness along the sample length in (<b>a</b>) CG and (<b>b</b>) UFG titanium depending on tension conditions: 1—without current; 2—j = 60 A/mm<sup>2</sup>, τ = 500 µs; 3—dryer, 200 °C.</p> Full article ">Figure 8
<p>Stress-strain curves for CG (<b>a</b>) and UFG (<b>b</b>) titanium: 1—without current; 2—j = 30 A/mm<sup>2</sup>, τ = 100 µs; 3—j = 30 A/mm<sup>2</sup>, τ = 1000 μs; 4—j = 60 A/mm<sup>2</sup>, τ = 100 μs.; 5—j = 60 A/mm<sup>2</sup>, τ = 500 μs; 6—dryer, 200 °C; Inset: Yield tooth on curve 5.</p> Full article ">Figure 9
<p>Fracture surface of CG (<b>a</b>,<b>b</b>) and UFG (<b>c</b>,<b>d</b>) Grade 4 under tension: (<b>a</b>,<b>c</b>)—no current; (<b>b</b>,<b>d</b>)—with current of j = 60 A/mm<sup>2</sup> τ = 100 μs.</p> Full article ">
17 pages, 4872 KiB  
Article
Comparative Investigation of the Influence of Ultrafine-Grained State on Deformation and Temperature Behavior and Microstructure Formed during Quasi-Static Tension of Pure Titanium and Ti-45Nb Alloy by Means of Infrared Thermography
by Elena Legostaeva, Anna Eroshenko, Vladimir Vavilov, Vladimir A. Skripnyak, Arsenii Chulkov, Alexander Kozulin, Vladimir V. Skripnyak, Ivan Glukhov and Yurii Sharkeev
Materials 2022, 15(23), 8480; https://doi.org/10.3390/ma15238480 - 28 Nov 2022
Cited by 3 | Viewed by 1311
Abstract
A comprehensive study was performed of the deformation and temperature behavior during quasi-static tension, as well as the peculiarities of accumulation and dissipation of energy during plastic deformation. Microstructural analysis at the pre-fracture stage of pure titanium and Ti-45Nb alloy in the coarse [...] Read more.
A comprehensive study was performed of the deformation and temperature behavior during quasi-static tension, as well as the peculiarities of accumulation and dissipation of energy during plastic deformation. Microstructural analysis at the pre-fracture stage of pure titanium and Ti-45Nb alloy in the coarse grain (CG) and ultrafine-grained (UFG) states was also conducted. It was shown that substructural and dispersion hardening leads to a change in the regularities of dissipation and accumulation energies during deformation of the samples of the pure titanium and Ti-45Nb alloy in the UFG state. Some features of structural transformations during deformation of the pure titanium and Ti-45Nb alloy samples in the CG and UFG states were studied. A band and cellular-network and fragmented dislocation structure was formed in the case of the CG state, while large anisotropic fragments were formed in the UFG state, thus specifying a local softening of the material before fracture. Full article
(This article belongs to the Section Advanced Materials Characterization)
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<p>Microstructure of the pure titanium (<b>a</b>–<b>d</b>) and Ti-45Nb alloy (<b>e</b>–<b>h</b>) in the CG (<b>a</b>,<b>e</b>) and UFG states (<b>b</b>–<b>d</b>,<b>f</b>–<b>h</b>): (<b>a</b>,<b>b</b>,<b>e</b>,<b>f</b>)—the BF TEM images with corresponding SAD patterns; (<b>d</b>,<b>h</b>)—the DF TEM images. The arrows show the reflections from the identified phases and the phases themselves.</p> Full article ">Figure 2
<p>True deformation <span class="html-italic">σ<sub>true</sub></span>(<span class="html-italic">ε<sub>true</sub></span>) curves (<b>a</b>), strain hardening coefficient <span class="html-italic">θ</span> (<span class="html-italic">ε<sub>true</sub></span>) <span class="html-italic">= dσ<sub>true</sub>/dε<sub>true</sub></span> (<b>b</b>) and temperature curves Δ<span class="html-italic">T</span>(<span class="html-italic">ε<sub>true</sub></span>) (<b>c</b>).</p> Full article ">Figure 3
<p>IR thermograms of deformed pure titanium sample in the CG state: 1—<span class="html-italic">ε</span> = 0.1; 2—<span class="html-italic">ε</span> = 0.11; 3—<span class="html-italic">ε</span> = 0.12; 4—<span class="html-italic">ε</span> = 0.125; 5—<span class="html-italic">ε</span> = 0.14; 6—<span class="html-italic">ε</span> = 0.155; 7—<span class="html-italic">ε</span> = 0.17; 8—<span class="html-italic">ε</span> = 0.18; 9—<span class="html-italic">ε</span> = 0.19; 10—<span class="html-italic">ε</span> = 0.205; 11—<span class="html-italic">ε</span> = 0.215; 12—<span class="html-italic">ε</span> = 0.225; 13—<span class="html-italic">ε</span> = 0.235; 14—<span class="html-italic">ε</span> = 0.24.</p> Full article ">Figure 4
<p>IR thermograms of deformed pure titanium sample in the UFG state: 1—<span class="html-italic">ε</span> = 0.05; 2—<span class="html-italic">ε</span> = 0.055; 3—<span class="html-italic">ε</span> = 0.06; 4—<span class="html-italic">ε</span> = 0.065; 5—<span class="html-italic">ε</span> = 0.07; 6—<span class="html-italic">ε</span> = 0.075; 7—<span class="html-italic">ε</span> = 0.08; 8—<span class="html-italic">ε</span> = 0.085; 9—<span class="html-italic">ε</span> = 0.09; 10—<span class="html-italic">ε</span> = 0.095; 11—<span class="html-italic">ε</span> = 0.10; 12—<span class="html-italic">ε</span> = 0.105; 13—<span class="html-italic">ε</span> = 0.11; 14—<span class="html-italic">ε</span> = 0.115.</p> Full article ">Figure 5
<p>IR thermograms of deformed sample of the Ti-45Nb alloy in the CG state: 1—ε = 0.065; 2—ε = 0.07; 3—ε = 0.075; 4—ε = 0.08; 5—ε = 0.09; 6—ε = 0.1; 7—ε = 0.11; 8—ε = 0.12; 9—ε = 0.13; 10—ε = 0.135; 11—ε = 0.14; 12—ε = 0.15; 13—ε = 0.155; 14—ε = 0.16.</p> Full article ">Figure 6
<p>IR thermograms of a deformed sample of the Ti-45Nb alloy in the UFG state: 1—<span class="html-italic">ε</span> = 0.055; 2—<span class="html-italic">ε</span> = 0.057; 3—<span class="html-italic">ε</span> = 0.06; 4—<span class="html-italic">ε</span> = 0.062; 5—<span class="html-italic">ε</span> = 0.064; 6—<span class="html-italic">ε</span> = 0.065; 7—<span class="html-italic">ε</span> = 0.066; 8—<span class="html-italic">ε</span> = 0.067; 9—<span class="html-italic">ε</span> = 0.068; 10—<span class="html-italic">ε</span> = 0.069; 11—<span class="html-italic">ε</span> = 0.07; 12—<span class="html-italic">ε</span> = 0.073; 13—<span class="html-italic">ε</span> = 0.075; 14—<span class="html-italic">ε</span> = 0.08.</p> Full article ">Figure 7
<p>Energy released during deformation as a function of the true strain. <span class="html-italic">Ap</span>—plastic deformation energy (<b>a</b>), <span class="html-italic">Q</span>—heat energy released during deformation (<b>b</b>), <span class="html-italic">Es</span>—energy stored in the process of deformation (<b>c</b>).</p> Full article ">Figure 8
<p>Microstructure of pure titanium in the CG state before fracture in the neck area: (<b>a</b>,<b>c</b>)—the BF TEM images with SAD patterns; (<b>b</b>,<b>d</b>)—the DF TEM images. Band structure (<b>a</b>,<b>b</b>) with cellular-network dislocation substructure (<b>c</b>,<b>d</b>).</p> Full article ">Figure 9
<p>Microstructure of pure titanium in the UFG state before fracture in the neck area: (<b>a</b>,<b>c</b>)—the BF TEM images with the SAD patterns; (<b>c</b>,<b>d</b>)—the DF TEM images. Band structure with a cellular-network dislocation substructure (<b>a</b>,<b>b</b>), large anisotropic fragments with a cellular-network dislocation substructure (<b>c</b>,<b>d</b>).</p> Full article ">Figure 10
<p>Microstructure of the Ti-45Nb alloy in the CG state before fracture in the neck area: (<b>a</b>,<b>b</b>,<b>d</b>,<b>e</b>)—the BF TEM images with the SAD patterns; (<b>c</b>,<b>f</b>)—the DF TEM images taken in reflections of ω- and β-phases. Band fragments (<b>a</b>–<b>c</b>) with a cellular-network dislocation substructure (<b>d</b>), fragmented substructure (<b>e</b>,<b>f</b>). Arrows show reflections from identified phases and phases.</p> Full article ">Figure 11
<p>Microstructure of the Ti-45Nb alloy in the UFG state before fracture in the neck area: (<b>a</b>,<b>c</b>)—the BF TEM images with the SAD patterns; (<b>b</b>,<b>d</b>)—the DF TEM images taken in (<b>b</b>) α-phase reflection and (β + ω)-phase reflection. Fragmented substructure (<b>a</b>,<b>b</b>), large anisotropic fragments with a cellular-network dislocation substructure (<b>c</b>,<b>d</b>). Arrows show reflections from identified phases and phases.</p> Full article ">
12 pages, 4493 KiB  
Article
Strength of Products Made of Ultrafine-Grained Titanium for Bone Osteosynthesis
by Gennadiy V. Klevtsov, Ruslan Z. Valiev, Luiza R. Rezyapova, Natal’ya A. Klevtsova, Maksim N. Tyurkov, Mikhail L. Linderov, Maksim V. Fesenyuk and Olesya A. Frolova
Materials 2022, 15(23), 8403; https://doi.org/10.3390/ma15238403 - 25 Nov 2022
Cited by 6 | Viewed by 1702
Abstract
This paper evaluates the fatigue strength of ultrafine-grained (UFG) Grade 4 Ti in the low-cycle fatigue region, as well as the strength of medical implants (plates and screws) made of UFG Ti under various types of loading in comparison with the strength of [...] Read more.
This paper evaluates the fatigue strength of ultrafine-grained (UFG) Grade 4 Ti in the low-cycle fatigue region, as well as the strength of medical implants (plates and screws) made of UFG Ti under various types of loading in comparison with the strength of products made of coarse-grained (CG) Ti. To produce a UFG state, titanium billets after annealing were processed by the ECAP-Conform technique. The fatigue of the prismatic specimens with a thickness of 10 mm from CG and UFG Ti was tested by the three-point bending method using an Instron 8802 facility. The modeling and evaluation of the stress-strain state in the ANSYS software package for finite-element analysis revealed, in particular, the localization of equivalent stresses in the area of hole edges and at fillets during the tension of the plates. The performed research has demonstrated that medical implants (plates and screws) from UFG Grade 4 Ti have a higher strength under different types of loading (tension, fatigue strength, torsion) in comparison with products from CG Ti. This opens up a possibility for the miniaturization of medical products from UFG Ti while preserving their main performance properties at an acceptable level. Full article
(This article belongs to the Special Issue Design and Applications of Functional Materials)
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<p>Solid (<b>a</b>) and mesh (<b>b</b>) models of a plate with bone fragments, and the respective loading principle (<b>c</b>).</p> Full article ">Figure 2
<p>Solid (<b>a</b>) and mesh (<b>b</b>) models of a screw with a bone fragment, and the respective loading principle (<b>c</b>).</p> Full article ">Figure 3
<p>Titanium deformation curves used to determine the elasto-plastic models of titanium.</p> Full article ">Figure 4
<p>Straight-line portion of the kinetic diagrams of fatigue fracture for CG Ti (bright dots) and UFG Ti (dark dots) at different values of the load ΔP, N.</p> Full article ">Figure 5
<p>Fatigue fracture surface microrelief of the specimens from CG (<b>a</b>–<b>c</b>) and UFG (<b>d</b>–<b>f</b>) Ti: (<b>a</b>,<b>d</b>) in the vicinity of the crack initiation nucleus; (<b>b</b>,<b>e</b>) in the vicinity of the final failure zone; (<b>c</b>,<b>f</b>) in the final failure zone; (<b>a</b>–<b>c</b>) ×1000, (<b>d</b>,<b>e</b>) ×2000; (<b>f</b>) ×4000.</p> Full article ">Figure 6
<p>Localized equivalent stresses emerging in different zones of the plates from Ti during tension (<b>a</b>) and the characteristic view of the UFG Ti plates after tensile tests (<b>b</b>). Zones 1 and 2 are located in the central region of the top and bottom parts of the plates; zones 3 and 4 are located at hole edges; zone 5 is located at the fillets of the plates.</p> Full article ">Figure 7
<p>Tensile curves for the plates from CG (<b>a</b>) and UFG (<b>b</b>) Ti.</p> Full article ">Figure 8
<p>Equivalent stress in a UFG Ti screw for its elastic (<b>a</b>) and elasto-plastic (<b>b</b>) models.</p> Full article ">Figure 9
<p>“Torque—rotation angle” diagrams based on the torsion tests of the screws from CG (<b>a</b>) and UFG (<b>b</b>) Ti.</p> Full article ">Figure 10
<p>Characteristic view (<b>a,e</b>) and microrelief of the fracture surfaces for the screws from CG (<b>a</b>–<b>d</b>) and UFG (<b>e</b>–<b>h</b>) Ti. The microrelief was obtained in the peripheral (<b>b</b>,<b>f</b>), transitional (<b>c</b>,<b>g</b>) and central (<b>d</b>,<b>h</b>) parts of the fracture surfaces; (<b>b</b>) ×1000; (<b>c</b>) ×850; (<b>d</b>) ×750; (<b>f</b>–<b>h</b>) ×6000.</p> Full article ">
30 pages, 51131 KiB  
Article
Development of Ultrafine–Grained and Nanostructured Bioinert Alloys Based on Titanium, Zirconium and Niobium and Their Microstructure, Mechanical and Biological Properties
by Yurii Sharkeev, Anna Eroshenko, Elena Legostaeva, Zhanna Kovalevskaya, Olga Belyavskaya, Margarita Khimich, Matthias Epple, Oleg Prymak, Viktoriya Sokolova, Qifang Zhu, Zeming Sun and Hongju Zhang
Metals 2022, 12(7), 1136; https://doi.org/10.3390/met12071136 - 2 Jul 2022
Cited by 13 | Viewed by 2071
Abstract
For this paper, studies of the microstructure as well as the mechanical and biological properties of bioinert titanium, zirconium, and niobium alloys in their nanostructured (NS) and ultrafine-grained (UFG) states have been completed. The NS and UFG states were formed by a combined [...] Read more.
For this paper, studies of the microstructure as well as the mechanical and biological properties of bioinert titanium, zirconium, and niobium alloys in their nanostructured (NS) and ultrafine-grained (UFG) states have been completed. The NS and UFG states were formed by a combined two-step method of severe plastic deformation (SPD), first with multidirectional forging (MDF) or pressing into a symmetrical channel (PSC) at a given temperature regime, and then subsequent multi-pass groove rolling (MPGR) at room temperature, with pre-recrystallization annealing. Annealing increased the plasticity of the alloys in the NS and UFG states without changing the grain size. The UFG structure, with an average size of structural elements of no more than 0.3 μm, was formed as a result of applying two-step SPD and annealing. This structure presented significant improvement in the mechanical characteristics of the alloys, in comparison with the alloys in the coarse-grained (CG) or small-grained (SG) states. At the same time, although the formation of the UFG structure leads to a significant increase in the yield strength and tensile strength of the alloys, their elastic modulus did not change. In terms of biocompatibility, the cultivation of MG-63 osteosarcoma cells on the polished and sandblasted substrates demonstrated high cell viability after 10 days and good cell adhesion to the surface. Full article
(This article belongs to the Special Issue Thermomechanical Treatment of Metals and Alloys)
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<p>MDF and MPGR: 1—initial billet (P—the arrows indicate the direction of applied load under pressing); 2—billet after first forging pass; 3–6—repeated forging passes with deformation axis rotation; 7—rolling; 8—billet formed after rolling in grooved rolls. “Reprinted with permission from ref. [<a href="#B88-metals-12-01136" class="html-bibr">88</a>] Copyright 2022 Springer Nature”.</p> Full article ">Figure 2
<p>PSC and MPGR: 1—billet before first pressing cycle (P—the arrows indicate the direction of applied load under pressing); 2—billet after the first pressing cycle; 3—repeating previous pressing cycles by rotating deformation axis; 4—rolling; 5—billet configuration after rolling in grooved rollers.</p> Full article ">Figure 3
<p>Dependence of UFG titanium microhardness on annealing time and temperature “Reprinted with permission from ref [<a href="#B87-metals-12-01136" class="html-bibr">87</a>] Copyright 2022 Springer Nature”.</p> Full article ">Figure 4
<p>Optical image (<b>a</b>), bright-field TEM image with corresponding microdiffraction pattern (<b>b</b>), histogram of the structure element size distribution of CG titanium (<b>c</b>).</p> Full article ">Figure 5
<p>Bright-field with corresponding microdiffraction patterns (<b>a</b>,<b>c</b>) and dark field (<b>b</b>,<b>d</b>) TEM images of titanium produced by MDF and MPGR (<b>a</b>,<b>b</b>), and PSC and MPGR (<b>c</b>,<b>d</b>).</p> Full article ">Figure 6
<p>Areas of bright-field TEM images (<b>a</b>,<b>c</b>) of the grain–subgrain structures, and histograms of element structure size distribution (<b>b</b>,<b>d</b>) of the titanium processed with MDF and MPGR (<b>a</b>,<b>b</b>) and PSC and MPGR (<b>c</b>,<b>d</b>).</p> Full article ">Figure 7
<p>The tensile engineering stress-strain curves (<b>a</b>), true stress-true strain curves (<b>b</b>), three-point bending diagram (<b>c</b>), and the dependence of stress σ on the number of fatigue cycles (<span class="html-italic">N</span>) (<b>d</b>) for pure titanium; 1—CG state, 2—UFG produced by MDF and MPGR, 3—NS, produced by PSC and MPGR. Arrows indicate those samples that did not fail during testing.</p> Full article ">Figure 8
<p>Optical image (<b>a</b>) and bright-field TEM image, with corresponding microdiffraction pattern (<b>b</b>); histograms of the element structure size distribution of the α-Zr phase (<b>c</b>) and β-Nb phase (<b>d)</b> of Zr-1Nb alloy in SG state.</p> Full article ">Figure 9
<p>Bright-field with corresponding microdiffraction pattern (<b>a</b>) and dark field (<b>b</b>) TEM images, with the distribution histogram of structure element sizes (<b>c</b>) of Zr-1Nb alloy after MDF and MPGR.</p> Full article ">Figure 10
<p>Niobium distribution map of Zr-1Nb alloy: bright field (<b>a</b>) and dark field (<b>b</b>) TEM images.</p> Full article ">Figure 11
<p>Tensile engineering stress-strain curves (<b>a</b>) and true stress-true strain curves (<b>b</b>), and three-point bending diagram (<b>c</b>) of the Zr-1Nb alloy; 1—SG state, 2—UFG state.</p> Full article ">Figure 12
<p>The dependence of stress σ on the number of fatigue cycles <span class="html-italic">N</span> for the Zr-1Nb alloy: 1—SG state; 2—UFG state. Arrows indicate those samples that did not fail during testing.</p> Full article ">Figure 13
<p>Optical image (<b>a</b>) and histogram of the structural element size distribution (<b>b</b>) of Ti-45Nb alloy.</p> Full article ">Figure 14
<p>Bright-field image with corresponding microdiffraction patterns in TEM images (<b>a</b>,<b>b</b>) and the α″-phase identification (<b>c</b>) of Ti-45Nb alloy under quenching: (<b>a</b>)—β-phase; (<b>b</b>)—α″-phase.</p> Full article ">Figure 15
<p>XRD pattern of Ti-45Nb alloy (Cu-Kα) after quenching (<b>a</b>) and with UFG (<b>b</b>).</p> Full article ">Figure 16
<p>Bright-field (<b>a</b>) and dark-field (<b>b</b>,<b>c</b>) TEM images, with corresponding microdiffraction patterns and histograms of the structure element size distribution of β-phase (<b>d</b>) and α-phase (<b>e</b>) of UFG Ti-45Nb, after MDF and MPGR.</p> Full article ">Figure 17
<p>Tensile engineering stress-strain curves (<b>a</b>) and true stress-true strain curves (<b>b</b>), and three-point bending diagram (<b>c</b>) of Ti-45Nb alloy: 1—CG state, 2—UFG state.</p> Full article ">Figure 18
<p>Dependence of the stress σ on the number of fatigue cycles <span class="html-italic">N</span> for the Ti-45Nb alloy: 1—CG state; 2—UFG state. Arrows indicate the samples that did not fail during the testing.</p> Full article ">Figure 19
<p>MTT analysis of the titanium, Zr-1Nb, and Ti-45Nb samples after MG-63 cell incubation for 10 days. Control: plastic plate; 1—polished samples, 2—sandblasted samples.</p> Full article ">Figure 20
<p>MG-63 osteosarcoma cells on a titanium sample surface after incubation for 10 days: (<b>a</b>,<b>b</b>)—titanium polished samples; (<b>c</b>,<b>d</b>)—titanium sandblasted samples.</p> Full article ">Figure 21
<p>MG-63 osteosarcoma cells on the Zr-1Nb sample surface after incubation for 10 days: (<b>a</b>,<b>b</b>)—Zr-1Nb polished samples; (<b>c</b>,<b>d</b>)—Zr-1Nb sandblasted samples.</p> Full article ">Figure 22
<p>MG-63 osteosarcoma cells on Ti-45Nb sample surface after incubation for 10 days: (<b>a</b>,<b>b</b>)—Ti-45Nb polished samples; (<b>c</b>,<b>d</b>)—Ti-45Nb sandblasted samples.</p> Full article ">Figure 23
<p>SEM images of the NS implant surface after mechanical treatment (<b>a</b>); a set of dental screw intraosseous implants, with instruments and accessories (<b>b</b>); X-ray topographic images of the internal cross-sectional dental implants (<b>c</b>).</p> Full article ">
16 pages, 3720 KiB  
Article
Effect of Structure and Hydrogen on the Short-Term Creep of Titanium Ti-2.9Al-4.5V-4.8Mo Alloy
by Galina Grabovetskaya, Ivan Mishin, Ekaterina Stepanova and Olga Zabudchenko
Materials 2022, 15(11), 3905; https://doi.org/10.3390/ma15113905 - 30 May 2022
Cited by 5 | Viewed by 1582
Abstract
In this paper, the effect of hydrogenation, in the amount of 0.15 wt.%, on the short-term creep of a titanium Ti-2.9Al-4.5V-4.8Mo alloy in fine-grained (FG) and ultrafine-grained (UFG) states is studied at 723 K. The UFG structure was formed by the method of [...] Read more.
In this paper, the effect of hydrogenation, in the amount of 0.15 wt.%, on the short-term creep of a titanium Ti-2.9Al-4.5V-4.8Mo alloy in fine-grained (FG) and ultrafine-grained (UFG) states is studied at 723 K. The UFG structure was formed by the method of pressing with the change of the deformation axis and gradual temperature decrease. Creep tests are performed under conditions of uniaxial tension at a constant load for the creep rates at an interval of (10−7 ÷ 10−6) s−1. The UFG alloy’s resistance to creep under the investigated conditions is revealed to be substantially lower than in the FG state. When hydrogen presents in the alloy in a solid solution, a 1.3–2.5-fold rise in the value of the steady-state creep rate for the hydrogenated FG and UFG alloys is observed. The creep of the non-hydrogenated FG and UFG alloys is described by the creep power law. The presence of dissolved hydrogen leads to a violation of the creep power law. The values of stress sensitivity indices, steady-state creep rate, and effective creep activation energy are determined. The relationships between the hydrogenation, structure, and creep mechanisms of the alloy at the steady-state are discussed. Full article
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<p>Microstructure (<b>a</b>) and diffraction patterns (<b>b</b>) of the FG titanium alloys.</p> Full article ">Figure 2
<p>TEM images of the UFG Ti-2.9Al-4.5V-4.8Mo alloy: (<b>a</b>) bright-field image and (<b>b</b>) corresponding SAED; (<b>c</b>) dark-field image in the reflection of (002)<sub>α</sub> type; (<b>d</b>) size distribution of grain–subgrain elements.</p> Full article ">Figure 3
<p>TEM images of the UFG Ti-2.9Al-4.5V-4.8Mo-0.15H alloy: (<b>a</b>) bright-field image and (<b>b</b>) corresponding SAED; (<b>c</b>) dark-field image in the reflection of (002)<sub>α</sub> type; (<b>d</b>) size distribution of grain–subgrain elements.</p> Full article ">Figure 3 Cont.
<p>TEM images of the UFG Ti-2.9Al-4.5V-4.8Mo-0.15H alloy: (<b>a</b>) bright-field image and (<b>b</b>) corresponding SAED; (<b>c</b>) dark-field image in the reflection of (002)<sub>α</sub> type; (<b>d</b>) size distribution of grain–subgrain elements.</p> Full article ">Figure 4
<p>Diffraction patterns of the UFG titanium alloys.</p> Full article ">Figure 5
<p>Tension curves of the FG and UFG Ti-2.9Al-4.5V-4.8Mo and Ti-2.9Al-4.5V-4.8Mo-0.15H alloys at 723 K.</p> Full article ">Figure 6
<p>Creep curves: (<b>a</b>) FG Ti-2.9Al-4.5V-4.8Mo and Ti-2.9Al-4.5V-4.8Mo-0.15H alloys and (<b>b</b>) UFG Ti-2.9Al-4.5V-4.8Mo and Ti-2.9Al-4.5V-4.8Mo-0.15H alloys obtained at 723 K.</p> Full article ">Figure 7
<p>Experimental dependences of the steady creep rate on the stress of the FG and UFG titanium alloys.</p> Full article ">Figure 8
<p>Fracture surface of the titanium alloys after creep at 723 K: (<b>a</b>) FG and (<b>b</b>) UFG Ti-2.9Al-4.5V-4.8Mo-0.15H; (<b>c</b>) FG and (<b>d</b>) UFG Ti-2.9Al-4.5V-4.8Mo.</p> Full article ">
12 pages, 4195 KiB  
Article
Enhanced Erosion Resistance of an Ultrafine-Grained Ti Alloy with a PVD Coating
by Roman R. Valiev, Konstantin S. Selivanov, Marina K. Smyslova, Yuri M. Dyblenko, Yana N. Savina, Ruslan Z. Valiev and Irina P. Semenova
Metals 2022, 12(5), 818; https://doi.org/10.3390/met12050818 - 9 May 2022
Cited by 4 | Viewed by 2034
Abstract
This paper presents the results of a comprehensive study of the erosive wear resistance, strength, and adhesive characteristics of the high-temperature structural titanium alloy Ti-5.7Al-3.8Mo-1.2Zr-1.3Sn (the Russian grade VT8M-1) with coarse-grained and ultrafine-grained (UFG) structures and a protective erosion-resistant TiVN coating produced by [...] Read more.
This paper presents the results of a comprehensive study of the erosive wear resistance, strength, and adhesive characteristics of the high-temperature structural titanium alloy Ti-5.7Al-3.8Mo-1.2Zr-1.3Sn (the Russian grade VT8M-1) with coarse-grained and ultrafine-grained (UFG) structures and a protective erosion-resistant TiVN coating produced by physical vapor deposition (PVD), deposited on the alloy surface. A microscopic analysis of the areas subjected to the action of abrasive particles was performed, and different characters of erosive wear were revealed depending on the structural state of the alloy. The obtained results convincingly demonstrate that by means of refining the grain structure of alloys and depositing a protective ion-plasma TiVN coating on the alloy surface, it is possible to significantly increase the erosion resistance of materials operating under high loads and in aggressive environments. Full article
(This article belongs to the Topic Surface Treatments for Protecting from Fracture and Fatigue Damage)
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<p>Principle of the erosive wear of the samples (<b>a</b>) and an optical image of the abrasive Al<sub>2</sub>O<sub>3</sub> particles (<b>b</b>).</p> Full article ">Figure 2
<p>Structure of the Ti alloy in different states: (<b>a</b>) CG after HT; (<b>b</b>) UFG, SEM; (<b>c</b>) UFG, TEM.</p> Full article ">Figure 3
<p>Coating architecture: (<b>a</b>) SEM image, (<b>b</b>) OM picture of the spherical section.</p> Full article ">Figure 4
<p>“Contact strength—penetration depth” mechanical curves: (<b>a</b>) CG + TiVN; (<b>b</b>) UFG + TiVN.</p> Full article ">Figure 5
<p>Erosive wear of coatings with zones of restricted (a–b) and normal (b–c) wear.</p> Full article ">Figure 6
<p>Image of the samples after erosive wear tests.</p> Full article ">Figure 7
<p>SEM image showing the erosive wear of the VT8M-1 samples: (<b>a</b>) CG state; (<b>b</b>) UFG state; 1—intergranular boundaries; 2—interphase boundaries; 3—intercrystalline fracture zones; 4—slip bands; 5—brittle facets.</p> Full article ">Figure 8
<p>SEM image showing the erosive wear of the VT8M-1 samples on cross sections: (<b>a</b>) CG state; (<b>b</b>) UFG state.</p> Full article ">
20 pages, 3046 KiB  
Article
The Effects of Chemical Etching and Ultra-Fine Grain Structure of Titanium on MG-63 Cells Response
by Denis Nazarov, Elena Zemtsova, Vladimir Smirnov, Ilya Mitrofanov, Maxim Maximov, Natalia Yudintceva and Maxim Shevtsov
Metals 2021, 11(3), 510; https://doi.org/10.3390/met11030510 - 19 Mar 2021
Cited by 7 | Viewed by 3325
Abstract
In this work, we study the influence of the surface properties of ultrafine grained (UFG) and coarse grained (CG) titanium on the morphology, viability, proliferation and differentiation of osteoblast-like MG-63 cells. Wet chemical etching in H2SO4/H2O2 [...] Read more.
In this work, we study the influence of the surface properties of ultrafine grained (UFG) and coarse grained (CG) titanium on the morphology, viability, proliferation and differentiation of osteoblast-like MG-63 cells. Wet chemical etching in H2SO4/H2O2 and NH4OH/H2O2 solutions was used for producing surfaces with varying morphology, topography, composition and wettability. The topography and morphology have been studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The composition was determined by time of flight mass-spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS). The results showed that it is possible to obtain samples with different compositions, hydrophilicity, topography and nanoscale or/and microscale structures by changing the etching time and the type of etching solution. It was found that developed topography and morphology can improve spreading and proliferation rate of MG-63 cells. A significant advantage of the samples of the UFG series in comparison with CG in adhesion, proliferation at later stages of cultivation (7 days), higher alkaline phosphatase (ALP) activity and faster achievement of its maximum values was found. However, there is no clear benefit of the UFG series on osteopontin (OPN) expression. All studied samples showed no cytotoxicity towards MG-63 cells and promoted their osteogenic differentiation. Full article
(This article belongs to the Special Issue Surface Modification of Metallic Biomaterials)
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<p>SEM images of chemically etched UFG and CG titanium discs: (<b>a</b>) UFG-SP-15; (<b>b</b>) UFG-SP-24; (<b>c</b>) UFG-AP-15; (<b>d</b>) UFG-AP-2; (<b>e</b>) CG-SP-15; (<b>f</b>) CG-SP-24; (<b>g</b>) CG-AP-15; (<b>h</b>) CG-AP-2. Reprinted with adaptation from [<a href="#B19-metals-11-00510" class="html-bibr">19</a>].</p> Full article ">Figure 2
<p>XPS spectra of polished and chemically etched UFG titanium: (<b>a</b>) N1s; (<b>b</b>) C1s; (<b>c</b>) Ti2p; (<b>d</b>) O1s.</p> Full article ">Figure 3
<p>TOF-SIMS spectra of negative ions: (<b>a</b>) UFG-Ti; (<b>b</b>) UFG-SP-24; (<b>c</b>) UFG-AP-2.</p> Full article ">Figure 4
<p>The morphology of MG-63 cells co-incubated after 24 h of cultivation. Scale bar—100 μm.</p> Full article ">Figure 5
<p>MG-63 cells viability after co-incubation on UFG and CG titanium. Data are presented as mean ± S.D. from five independent series of experiments (<span class="html-italic">p</span> &lt; 0.05).</p> Full article ">Figure 6
<p>MG-63 cells proliferation activity after co-incubation on: (<b>a</b>) UFG samples; (<b>b</b>) CG samples. Data are presented as mean ± S.D. from five independent series of experiments (<span class="html-italic">p</span> &lt; 0.05).</p> Full article ">Figure 7
<p>Alkaline phosphatase production by MC3T3-E1 osteoblasts on UFG series—(<b>a</b>) and CG series—(<b>b</b>). Each value represents mean ± S.D. from five independent experiments (<span class="html-italic">p</span> &lt; 0.05).</p> Full article ">Figure 8
<p>Osteopontin production by MC3T3-E1 osteoblasts on UFG series—(<b>a</b>) and CG series—(<b>b</b>). Each value represents mean ± S.D. from five independent experiments (<span class="html-italic">p</span> &lt; 0.05).</p> Full article ">
24 pages, 4319 KiB  
Review
Biological Applications of Severely Plastically Deformed Nano-Grained Medical Devices: A Review
by Katayoon Kalantari, Bahram Saleh and Thomas J. Webster
Nanomaterials 2021, 11(3), 748; https://doi.org/10.3390/nano11030748 - 16 Mar 2021
Cited by 22 | Viewed by 3176
Abstract
Metallic materials are widely used for fabricating medical implants due to their high specific strength, biocompatibility, good corrosion properties, and fatigue resistance. Recently, titanium (Ti) and its alloys, as well as stainless steel (SS), have attracted attention from researchers because of their biocompatibility [...] Read more.
Metallic materials are widely used for fabricating medical implants due to their high specific strength, biocompatibility, good corrosion properties, and fatigue resistance. Recently, titanium (Ti) and its alloys, as well as stainless steel (SS), have attracted attention from researchers because of their biocompatibility properties within the human body; however, improvements in mechanical properties while keeping other beneficial properties unchanged are still required. Severe plastic deformation (SPD) is a unique process for fabricating an ultra-fine-grained (UFG) metal with micrometer- to nanometer-level grain structures. SPD methods can substantially refine grain size and represent a promising strategy for improving biological functionality and mechanical properties. This present review paper provides an overview of different SPD techniques developed to create nano-/ultra-fine-grain-structured Ti and stainless steel for improved biomedical implant applications. Furthermore, studies will be covered that have used SPD techniques to improve bone cell proliferation and function while decreasing bacterial colonization when cultured on such nano-grained metals (without resorting to antibiotic use). Full article
(This article belongs to the Special Issue Application and Evaluation Method of Nanomaterial in Bone Regenerative Medicine)
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<p>The severe plastic deformation (SPD) process can be thought of as the impact of a hammer on a window glass.</p> Full article ">Figure 2
<p>A schematic showing the working details of the equal-channel angular press (ECAP) process; first (<b>A</b>), intermediate (<b>B</b>), and final (<b>C</b>) steps.</p> Full article ">Figure 3
<p>Principle of the ECAP–conformation technique (<b>A</b>); reproduced from [<a href="#B45-nanomaterials-11-00748" class="html-bibr">45</a>]; Schematic illustration of the high-pressure torsion (HPT) process (<b>B</b>); reproduced from [<a href="#B46-nanomaterials-11-00748" class="html-bibr">46</a>].</p> Full article ">Figure 4
<p>Schematic of a hydrostatic extrusion (HE) device (<b>A</b>); reproduced from [<a href="#B47-nanomaterials-11-00748" class="html-bibr">47</a>] with permission from Elsevier, 2020. Schematic of the twist extrusion (TE) process (<b>B</b>).</p> Full article ">Figure 5
<p>Schematic of the friction stir process (<b>A</b>) and severe shot peening (<b>B</b>); reproduced from [<a href="#B54-nanomaterials-11-00748" class="html-bibr">54</a>], from Elsevier, 2020.</p> Full article ">Figure 6
<p>Overall view of the ultrasonic shot peening (USSP) process; reproduced from [<a href="#B57-nanomaterials-11-00748" class="html-bibr">57</a>], with permission from Elsevier, 2020.</p> Full article ">Figure 7
<p>Schematic drawing of multidirectional deformation rolling realized using an oval-caliber and square-caliber rolling (<b>A</b>); redrawn from [<a href="#B60-nanomaterials-11-00748" class="html-bibr">60</a>]. A schematic illustration of a novel advanced warm continuous oval- to square-rolling set-up (<b>B</b>); reproduced from [<a href="#B60-nanomaterials-11-00748" class="html-bibr">60</a>], with permission from Elsevier, 2020.</p> Full article ">Figure 8
<p>Schematic drawing of caliber rolling (<b>A</b>); reproduced from [<a href="#B60-nanomaterials-11-00748" class="html-bibr">60</a>], with permission from Elsevier, 2020. A schematic diagram of the cold-rolling system (<b>B</b>).</p> Full article ">Figure 9
<p>Accumulative roll bonding (<b>A</b>); reproduced from [<a href="#B6-nanomaterials-11-00748" class="html-bibr">6</a>], with permission from Elsevier, 2020. A schematic of the cryo-rolling process (<b>B</b>); reproduced from [<a href="#B73-nanomaterials-11-00748" class="html-bibr">73</a>], with permission from Elsevier, 2021.</p> Full article ">Figure 10
<p>A schematic illustration of the sequences of the constrained groove-pressing (CGP) technique; groove pressing stage (<b>A</b>,<b>B</b>), sample is rotated by 180° (<b>D</b>), the successive pressings with a grooved die (<b>E</b>), a flat die (<b>F</b>), reproduced from [<a href="#B76-nanomaterials-11-00748" class="html-bibr">76</a>,<a href="#B79-nanomaterials-11-00748" class="html-bibr">79</a>], with permission from Elsevier, 2021.</p> Full article ">Figure 11
<p>Scanning electron microscopy (SEM) micromorphology of UFG Ti (<b>a</b>) and CP Ti (<b>b</b>) adapted from [<a href="#B10-nanomaterials-11-00748" class="html-bibr">10</a>], with permission from Elsevier, 2020.</p> Full article ">Figure 12
<p>SEM figures of MC3T3-E1 cells on the surfaces of CP Ti (<b>a</b>,<b>b</b>) and UFG Ti (<b>c</b>,<b>d</b>). In these images, (<b>a</b>,<b>c</b>) and (<b>b</b>,<b>d</b>) show cell adhesion after 2 and 24 h of incubation, respectively, adapted from [<a href="#B10-nanomaterials-11-00748" class="html-bibr">10</a>], with permission from Elsevier, 2020.</p> Full article ">Figure 13
<p>X-ray film (<b>a</b>) and reconstructed micro-CT image (<b>b</b>) from a model with an implant. The illustration in the upper-right corner of image (<b>b</b>) is the reconstructed image of the bone within the region of interest, adapted from [<a href="#B10-nanomaterials-11-00748" class="html-bibr">10</a>], with permission from Elsevier, 2020.</p> Full article ">
9 pages, 2770 KiB  
Article
Structural Characteristics of Multilayered Ni-Ti Nanocomposite Fabricated by High Speed High Pressure Torsion (HSHPT)
by Gheorghe Gurau, Carmela Gurau, Francisco Manuel Braz Fernandes, Petrica Alexandru, Vedamanickam Sampath, Mihaela Marin and Bogdan Mihai Galbinasu
Metals 2020, 10(12), 1629; https://doi.org/10.3390/met10121629 - 4 Dec 2020
Cited by 10 | Viewed by 1913
Abstract
It is generally accepted that severe plastic deformation (SPD) has the ability to produce ultrafinegrained (UFG) and nanocrystalline materials in bulk. Recent developments in high pressure torsion (HPT) processes have led to the production of bimetallic composites using copper, aluminum or magnesium alloys. [...] Read more.
It is generally accepted that severe plastic deformation (SPD) has the ability to produce ultrafinegrained (UFG) and nanocrystalline materials in bulk. Recent developments in high pressure torsion (HPT) processes have led to the production of bimetallic composites using copper, aluminum or magnesium alloys. This article outlines a new approach to fabricate multilayered Ni-Ti nanocomposites by a patented SPD technique, namely, high speed high pressure torsion (HSHPT). The multilayered composite discs consist of Ni-Ti alloys of different composition: a shape memory alloy (SMA) Ti-rich, whose Mf > RT, and an SMA Ni-rich, whose Af < RT. The composites were designed to have 2 to 32 layers of both alloys. The layers were arranged in different sequences to improve the shape recovery on both heating and cooling of nickel-titanium alloys. The manufacturing process of Ni-Ti multilayers is explained in this work. The evolution of the microstructure was traced using optical, scanning electron and transmission electron microscopes. The effectiveness of the bonding of the multilayered composites was investigated. The shape memory characteristics and the martensitic transition of the nickel-titanium nanocomposites were studied by differential scanning calorimetry (DSC). This method opens up new possibilities for designing various layered metal-matrix composites achieving the best combination of shape memory, deformability and tensile strength. Full article
(This article belongs to the Special Issue Hybrid Bulk Metal Components)
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<p>Processing route of Ni<sub>50.3</sub>Ti/Ni<sub>49.6</sub>Ti composite discs cut in half and assembled as sandwich stacks with: (<b>a</b>) number of layers multiple of 2 and (<b>b</b>) number of layers multiple of 3.</p> Full article ">Figure 2
<p>Optical micrograph of Ni<sub>50.3</sub>Ti/Ni<sub>49.6</sub>Ti composite discs: (<b>a</b>) bright field image of three layers and (<b>b</b>) dark field image of 24 layers.</p> Full article ">Figure 3
<p>SEM image of HSHPT-processed metallic composite: (<b>a</b>) 12 layers, (<b>b</b>) 24 layers.</p> Full article ">Figure 4
<p>TEM image of the 4 layered Ni<sub>50.3</sub>Ti/Ni<sub>49.6</sub>Ti composite.</p> Full article ">Figure 5
<p>DSC curves of the 4 (black), 16 (blue) and 32 (red) layered Ni<sub>50.3</sub>Ti/Ni<sub>49.6</sub>Ti composites after HSHPT.</p> Full article ">Figure 6
<p>DSC curves for the 32 layers of Ni<sub>50.3</sub>Ti/Ni<sub>49.6</sub>Ti composite after HSHPT. Thicker lines: center sample; thinner lines: edge sample.</p> Full article ">
15 pages, 7456 KiB  
Article
Analyzing the Deformation and Fracture of Bioinert Titanium, Zirconium and Niobium Alloys in Different Structural States by the Use of Infrared Thermography
by Yurii Sharkeev, Vladimir Vavilov, Vladimir A. Skripnyak, Olga Belyavskaya, Elena Legostaeva, Alexander Kozulin, Arsenii Chulkov, Alexey Sorokoletov, Vladimir V. Skripnyak, Anna Eroshenko and Marina Kuimova
Metals 2018, 8(9), 703; https://doi.org/10.3390/met8090703 - 6 Sep 2018
Cited by 18 | Viewed by 3244
Abstract
Bioinert metals are used for medical implants and in some industrial applications. This study was performed to detect and analyze peculiarities that appear in the temperature distributions during quasi-static tensile testing of bioinert alloys. These alloys include VT1-0 titanium, Zr-1%Nb and Ti-45%Nb in [...] Read more.
Bioinert metals are used for medical implants and in some industrial applications. This study was performed to detect and analyze peculiarities that appear in the temperature distributions during quasi-static tensile testing of bioinert alloys. These alloys include VT1-0 titanium, Zr-1%Nb and Ti-45%Nb in both coarse-grain (CG) and ultrafine-grain (UFG) states. The crystal structure, as well as the crystal domain and grain sizes of these alloys in the UFG state, may be different from the CG versions and identifying the thermal signatures that occur during their deformation and fracture is of interest, as it may lead to an understanding of physical processes that occur during loading. By comparing the surface temperature distributions of specimens undergoing deformation under tensile loading to the distributions at maximum temperatures it was found that the observed differences depend on the alloy type, the alloy structural state and the thermal properties of structural defects in the specimen. Macro-defects were found in some specimens of VT1-0 titanium, Zr-1Nb and Ti-45Nb alloys in both the CG and UFG states. The average tensile strength of specimens containing defects was lower than that of specimens with no defects. Infrared thermography documents change in the thermal patterns of specimens as they are deformed under tensile loading and when the load stops changing or the specimen breaks. Full article
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<p>Test specimen scheme.</p> Full article ">Figure 2
<p>“Engineering stress-engineering strain” diagrams for VT1-0 titanium (<b>a</b>), Zr-1Nb (<b>b</b>) and Ti-45Nb (<b>c</b>) alloys.</p> Full article ">Figure 3
<p>True stress-true strain diagrams for VT1-0 titanium (<b>a</b>), Zr-1Nb (<b>b</b>) and Ti-45Nb (<b>c</b>) alloys in the CG (curves 1) and UFG (curves 2) states.</p> Full article ">Figure 4
<p>IR thermograms of VT1-0 titanium in the CG state during tensile test: 1—ε = 11.2%, 2—ε = 11.9%, 3—ε = 13%, 4—ε = 15.4%, 5—ε = 16.9%, 6—ε = 18.6%, 7—ε = 19.4%, 8—ε = 20.7%, 9—ε = 21.5%, 10—ε = 22.8%, 11—ε = 24.2%, 12—ε = 25.2%, 13—ε = 25.4%, 14—ε = 25.5%.</p> Full article ">Figure 5
<p>IR thermograms of VT1-0 titanium in the UFG state during tensile test: 1—ε = 3.5%, 2—ε = 3.8%, 3—ε = 3.9%, 4—ε = 4.1%, 5—ε = 4.5%, 6—ε = 5.5%, 7—ε = 6.3%, 8—ε = 6.8%, 9—ε = 7.4%, 10—ε = 7.8%, 11—ε = 9.6%, 12—ε = 10.4%, 13—ε = 11%, 14—ε = 11.4%.</p> Full article ">Figure 6
<p>IR thermograms of Zr-1%Nb alloy in the CG state during tensile test: 1—ε = 10.8%, 2—ε = 11.7%, 3—ε = 12.6%, 4—ε = 13.5%, 5—ε = 15.2%, 6—ε = 16.6%, 7—ε = 18.3%, 8—ε = 19.2%, 9—ε = 20.6%, 10—ε = 22.7%, 11—ε = 24.1%, 12—ε = 25.8%, 13—ε = 26.6%, 14—ε = 27.2%.</p> Full article ">Figure 7
<p>IR thermograms of Zr-1Nb alloy in the UFG state during tensile test: 1—ε = 9.3%, 2—ε = 9.6%, 3—ε = 9.8%, 4—ε = 10.7%, 5—ε = 11%, 6—ε = 11.3%, 7—ε = 11.9%, 8—ε = 12.5%, 9—ε = 12.5%, 10—ε = 13.1%, 11—ε = 14.1%, 12—ε = 14.7%, 13—ε = 14.9%, 14—ε = 15%.</p> Full article ">Figure 8
<p>IR thermograms of Ti-45 Nb alloy in the CG state during tensile test: 1—ε = 4.6%, 2—ε = 4.8%, 3—ε = 5.2%, 4—ε = 6.1%, 5—ε = 7.1%, 6—ε = 7.9%, 7—ε = 8.8%, 8—ε = 9.8%, 9—ε = 10.5%, 10—ε = 11.6%, 11—ε = 12.3%, 12—ε = 14.2%, 13—ε = 14.5%, 14—ε = 14.8%.</p> Full article ">Figure 9
<p>IR thermograms of Ti-45Nb alloy in the UFG state during tensile test: 1—ε = 3.9%, 2—ε = 4%, 3—ε = 4.1%, 4—ε = 4.3%, 5—ε = 4.5%, 6—ε = 4.6%, 7—ε = 4.8%, 8—ε = 4.9%, 9—ε = 5%, 10—ε = 5.2%, 11—ε = 5.3%, 12—ε = 5.4%, 13—ε = 5.7%, 14—ε = 6%.</p> Full article ">Figure 10
<p>Temperature evolutions on surface of specimens subjected to tensile test: VT1-0 titanium (<b>a</b>), Zr-1Nb (<b>b</b>) and Ti-45Nb (<b>c</b>) alloys.</p> Full article ">Figure 11
<p>SEM images of the surface of the fracture specimens subjected to tensile test: VT1-0 titanium specimens (<b>a</b>,<b>b</b>,<b>g</b>), Zr-1 Nb (<b>c</b>) and Ti-45Nb (<b>e</b>,<b>f</b>) alloys in the CG (<b>a</b>,<b>c</b>,<b>e</b>) and UFG (<b>b</b>,<b>d</b>,<b>f</b>,<b>g</b>,<b>h</b>) states.</p> Full article ">Figure 11 Cont.
<p>SEM images of the surface of the fracture specimens subjected to tensile test: VT1-0 titanium specimens (<b>a</b>,<b>b</b>,<b>g</b>), Zr-1 Nb (<b>c</b>) and Ti-45Nb (<b>e</b>,<b>f</b>) alloys in the CG (<b>a</b>,<b>c</b>,<b>e</b>) and UFG (<b>b</b>,<b>d</b>,<b>f</b>,<b>g</b>,<b>h</b>) states.</p> Full article ">
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