CN115386815A - A copper-containing AlCoCrFeNi eutectic composition as-cast high-entropy alloy and a method for simultaneously improving strength and plasticity - Google Patents

Abstract

The invention discloses a copper-containing AlCoCrFeNi eutectic composition as-cast high-entropy alloy and a method for simultaneously improving strength and plasticity. The method of the invention comprises the following steps: cutting the copper-containing AlCoCrFeNi eutectic composition as-cast high-entropy alloy to obtain a rectangular block; carrying out homogenizing annealing on the rectangular block to obtain an annealing material; and sequentially rolling and recrystallizing and annealing the annealed material, wherein the temperature of recrystallization and annealing is 600-850 ℃. The method of the invention enables the as-cast high-entropy alloy to be free of complex processes such as hot forging and forging, and the strength and the plasticity can be improved simultaneously by simple normal-temperature rolling and annealing. The method can ensure that the high-entropy alloy has high tensile strength and good plasticity at the same time, is safe, reliable and practical, and has very wide application prospect in the engineering field.

Description

A copper-containing AlCoCrFeNi eutectic composition as-cast high-entropy alloy and simultaneous strength enhancement with plastic methods

technical field

The invention relates to a cast high-entropy alloy with copper-containing AlCoCrFeNi eutectic composition and a method for simultaneously improving strength and plasticity, and belongs to the technical field of high-entropy alloy structure regulation technology.

Background technique

High-entropy alloys are a class of multi-principal alloys with simple phase composition that are composed of four or more different metal elements mixed in an equiatomic ratio or approximately equiatomic ratio. Unlike traditional metals, due to the complexity of the composition of high-entropy alloy elements, a small change in the content of alloy elements can cause a strong change in the microstructure, which makes the properties of high-entropy alloys difficult to predict. At present, the research on high-entropy alloys is still in the early stage. High-entropy alloys prepared by existing technologies usually cannot achieve both high strength and good plasticity, and high-entropy alloys with excellent mechanical properties often require complex deformation heat treatment processes, making actual production difficult. Therefore, the current scientific and technological bottleneck is how to improve the comprehensive mechanical properties of high-entropy alloys, simplify the production process, and realize industrial applications.

Copper-containing AlCoCrFeNi eutectic high-entropy alloys are one of the types of high-entropy alloys with high strength and wide application. Hot forging can improve the inhomogeneity of the as-cast high-entropy alloy structure and improve metal plasticity, but it has high energy consumption, high noise and low processing efficiency. The rolling process can effectively increase the strength of high-entropy alloys, but it will inevitably lead to a sharp decrease in plasticity. Bimodal structure is a metal material with two grains of different sizes at the same time, which can balance strength and plasticity, but obtaining bimodal structure often requires complex structure control and deformation heat treatment processes such as thermal deformation and multi-temperature interval annealing. It will increase energy consumption, increase the difficulty of industrial production, and hinder the process of industrial application. How to obtain a copper-containing AlCoCrFeNi eutectic composition high-entropy alloy with bimodal structure and excellent mechanical properties through a simple deformation heat treatment method has become an urgent technical problem to be solved.

Contents of the invention

The technical problem to be solved by the present invention is: how to obtain a bimodal high-entropy alloy with copper-containing AlCoCrFeNi eutectic composition with excellent mechanical properties through a simple deformation heat treatment method.

In order to solve the above-mentioned technical problems, the present invention provides a method for simultaneously improving the strength and plasticity of a copper-containing AlCoCrFeNi eutectic composition as-cast high-entropy alloy, which is characterized in that it comprises the following steps:

Cutting the cast high-entropy alloy with copper-containing AlCoCrFeNi eutectic composition to obtain a rectangular block;

performing homogenization annealing on the rectangular block to obtain an annealed material;

The annealed material is sequentially subjected to rolling and recrystallization annealing, and the temperature of the recrystallization annealing is 600-850°C.

Preferably, the temperature of the homogenization annealing is 1000-1200° C., and the time is 4-48 hours.

Preferably, both the homogenization annealing and the recrystallization annealing are performed in an inert protective gas.

Preferably, the rolling deformation is 75%-95%.

Preferably, the recrystallization annealing time is 3-8 hours.

More preferably, the temperature of the recrystallization annealing is 700-800° C., and the time is 4-6 hours.

Preferably, cooling is also included after the homogenization annealing.

Preferably, the thickness of the rectangular block is greater than 6mm and not more than 1/2 of the width of the rectangular block.

Preferably, the composition of the copper-containing AlCoCrFeNi eutectic cast high-entropy alloy is Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 .

The present invention also provides the copper-containing AlCoCrFeNi eutectic composition high-entropy alloy obtained by the method described in the above technical solution, characterized in that the tensile strength of the copper-containing AlCoCrFeNi eutectic composition high-entropy alloy is 1406.0-1729.2MPa, and the extension The rate is 22.6% to 24.3%.

The invention provides a method for simultaneously improving the strength and plasticity of an as-cast high-entropy alloy containing copper-containing AlCoCrFeNi eutectic composition, comprising the following steps: cutting the as-cast high-entropy alloy containing copper-containing AlCoCrFeNi eutectic composition to obtain a rectangular block; The rectangular block is subjected to homogenization annealing to obtain an annealed material; the annealed material is sequentially subjected to rolling and recrystallization annealing, and the temperature of the recrystallization annealing is 600-850°C. The present invention has determined various process parameters through multiple tests, especially the recrystallization annealing temperature is the optimum temperature range obtained through countless tests. When the recrystallization annealing temperature is lower than 600 ° C, the copper-containing AlCoCrFeNi eutectic composition is high The strength of the entropy alloy is greatly improved but the plasticity is decreased.

Compared with prior art, the beneficial effect of the present invention is:

1. The present invention can greatly improve the tensile strength of the cast high-entropy alloy containing copper-containing AlCoCrFeNi eutectic composition while increasing the elongation rate, and can obtain high-entropy alloys with different strength-plasticity matching on demand by changing the annealing temperature, It has broad application prospects in the engineering field;

2. The present invention obtains a copper-containing AlCoCrFeNi eutectic high-entropy alloy with both strength and plasticity through a simple deformation heat treatment method. The high-entropy alloy has a tensile strength of 1406.0-1729.2MPa and an elongation of 22.6% ~ 24.3%, has great potential in practical application, and has the advantage of stable organization in medium and high temperature environments; in addition, the method of the present invention has simple steps, is safe, reliable and practical, and can realize the automatic and convenient production of assembly line industry.

Description of drawings

Fig. 1 is the photograph after the stretching of a kind of copper-containing AlCoCrFeNi eutectic component high-entropy alloy sample prepared through 700 ℃ annealing of embodiment 1;

Fig. 2 is the static tensile engineering stress-strain curve diagram of a kind of copper-containing AlCoCrFeNi eutectic composition high-entropy alloy sample prepared by embodiment 1 annealed at 700°C;

Fig. 3 is the EBSD-ipf figure of a kind of copper-containing AlCoCrFeNi eutectic component high-entropy alloy sample prepared through 700 DEG C annealed in embodiment 1;

Fig. 4 is the photograph after the stretching of a kind of copper-containing AlCoCrFeNi eutectic component high-entropy alloy sample prepared through 800 ℃ annealing prepared in embodiment 2;

Fig. 5 is the static tensile engineering stress-strain curve diagram of a kind of copper-containing AlCoCrFeNi eutectic component high-entropy alloy sample prepared through 800 DEG C annealed in embodiment 2;

Fig. 6 is the photograph after stretching of a kind of copper-containing AlCoCrFeNi eutectic component high-entropy alloy sample prepared by comparative example 1 annealed at 450°C;

Fig. 7 is the static tensile engineering stress-strain curve of a kind of copper-containing AlCoCrFeNi eutectic composition high-entropy alloy sample prepared by comparative example 1 annealed at 450°C;

Fig. 8 is the EBSD-ipf diagram of a kind of copper-containing AlCoCrFeNi eutectic component high-entropy alloy sample prepared by comparative example 1 annealed at 450°C;

9 is a photo of a copper-containing AlCoCrFeNi eutectic high-entropy alloy sample prepared in Comparative Example 2 after stretching;

10 is a static tensile engineering stress-strain curve of a copper-containing AlCoCrFeNi eutectic high-entropy alloy sample prepared in Comparative Example 2 and annealed at 550°C.

Detailed ways

In order to make the present invention more comprehensible, preferred embodiments are described in detail below with accompanying drawings.

The invention provides a method for simultaneously improving the strength and plasticity of a copper-containing AlCoCrFeNi eutectic composition as-cast high-entropy alloy, comprising the following steps:

Cutting the cast high-entropy alloy with copper-containing AlCoCrFeNi eutectic composition to obtain a rectangular block;

performing homogenization annealing on the rectangular block to obtain an annealed material;

The annealed material is sequentially subjected to rolling and recrystallization annealing, and the temperature of the recrystallization annealing is 600-850°C.

The invention cuts the cast high-entropy alloy containing copper AlCoCrFeNi eutectic composition to obtain a rectangular block.

In the present invention, the composition of the copper-containing AlCoCrFeNi eutectic composition cast high-entropy alloy is preferably Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 .

In the present invention, the tensile strength of the Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 is preferably 950.0±25.0 MPa, and the elongation is preferably 16.0±0.5%.

In the present invention, the thickness of the rectangular block is preferably greater than 6mm, and not more than 1/2 of the width of the cast high-entropy alloy with copper-containing AlCoCrFeNi eutectic composition. The present invention has no special limitation on the specific manner of cutting.

After the rectangular block is obtained, the present invention performs uniform annealing on the rectangular block to obtain an annealed material.

In the present invention, the homogenization annealing temperature is preferably 1000-1200° C., more preferably 1150° C., and the time is preferably 4-48 hours.

In the present invention, the homogenization annealing is preferably performed in a protective gas, and the protective gas is preferably argon, and the homogenization annealing is preferably performed in a box-type resistance furnace.

In the present invention, cooling is preferably included after the homogenization annealing, and the cooling is preferably natural cooling to room temperature.

After the annealed material is obtained, the present invention sequentially performs rolling and recrystallization annealing on the annealed material.

In the present invention, the rolling deformation is preferably 75% to 95%, more preferably 80% to 85%.

In the present invention, the recrystallization annealing temperature is 600-850° C., preferably 700-800° C., and the time is preferably 3-8 hours, more preferably 4-6 hours.

In the present invention, the recrystallization annealing is preferably performed in a protective gas, and the protective gas is preferably argon, and the recrystallization annealing is preferably performed in a box-type resistance furnace.

The present invention also provides the copper-containing AlCoCrFeNi eutectic composition high-entropy alloy obtained by the method described in the above technical solution, the tensile strength of the copper-containing AlCoCrFeNi eutectic composition high-entropy alloy is 1406.0-1729.2MPa, and the elongation is 22.6% ~24.3%.

The process equipment and testing equipment involved in the following embodiments are as follows:

Homogenization annealing and recrystallization annealing of samples were performed using Hefei Kejing OTF-1200X tube furnace;

Use Ф180 two-roll rolling mill to roll the sample, and the final rolling volume should not be less than 75%;

Microstructure: Axio Observer D1M inverted metallographic microscope produced by Carl Zeiss was used for metallographic observation; the sample was first inlaid with phenolic resin, and then polished with 400#, 600#, 1000#, 1500#, 3000# silicon carbide sandpaper, Polishing with diamond polishing paste with a particle size of 0.5 μm; scanning electron microscope and EBSD analysis using Gemini 300 field emission scanning electron microscope and EDAX-TSL electron backscattering diffraction system produced by Carl Zeiss;

Quasi-static tensile mechanical performance test: according to the standard GB/T228.1-2010, use Zwick Z020 microcomputer-controlled electronic universal testing machine to conduct axial quasi-static tensile test at room temperature, the strain rate is selected as 10 ^-3 s ^-1 , and the test sample It is a non-standard I-shaped piece, with a thickness of 0.60mm, a length of 12.00mm, a gauge length of 5.00mm, and a gauge width of 1.70mm.

Example 1

A deformation heat treatment method for improving the strong plasticity of a copper-containing AlCoCrFeNi eutectic composition cast high-entropy alloy is used to improve the tensile strength of the Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 high-entropy alloy while increasing the plasticity.

The deformation heat treatment method is as follows:

Step 1: Sample pretreatment:

Clean the as-cast Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 high-entropy alloy block and cut it into a rectangular block of 6mm×20mm×40mm;

Step 2: Homogenization annealing:

First turn on the tube furnace and preheat it to 1150°C; put the high-entropy alloy block into an alumina ceramic crucible and put it into the tube furnace; open the protective gas charging valve and fill the furnace tube with high-purity 99.999% pure Argon to complete the gas protection process; take out the sample after homogenization annealing for 4 hours, and quickly cool to room temperature.

Step Three: Rolling:

The rolling mill was started, and the high-entropy alloy block after homogenization annealing was rolled at room temperature, and the thickness of the sample was rolled from 6 mm to 0.6 mm.

Step 4: Recrystallization annealing:

Cut the high-entropy alloy obtained in step 3 into a rectangular plate of 0.6mm×20mm×40mm; turn on the tube furnace and preheat it to 700°C; put the high-entropy alloy block into an alumina ceramic crucible and put it into the tube furnace ; Open the protective gas inflation valve, fill the furnace tube with high-purity argon gas with a purity of 99.999%, and complete the gas protection process; take out the sample after 4 hours of recrystallization annealing, and quickly cool it to room temperature.

Experimental test analysis:

Fig. 1 is a photo of a copper-containing AlCoCrFeNi eutectic high-entropy alloy sample prepared in Example 1 after stretching and annealed at 700°C.

The deformation heat-treated high-entropy alloy sheet prepared in this example and subjected to recrystallization annealing at 700°C was used as a test sample for experimental inspection. According to the tensile test results in Figure 2, it can be seen that the tensile strength of the original cast alloy is 950.0 MPa, and the elongation at break is Compared with the elongation rate of 16.0%, the tensile strength of the high-entropy alloy sheet annealed at 700°C increased to 1729.2MPa, and the elongation at break increased to 22.6%;

From the EBSD-ipf diagram in Figure 3, it can be seen that the structure of the high-entropy alloy plate annealed at 700 °C is a bimodal structure with large grains in the matrix and fine grains distributed along the shear band.

Example 2

A deformation heat treatment method for improving the strong plasticity of a copper-containing AlCoCrFeNi eutectic composition cast high-entropy alloy is used to improve the tensile strength of the Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 high-entropy alloy while increasing the plasticity.

The deformation heat treatment method is as follows:

Step 1: Sample pretreatment:

Clean the as-cast Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 high-entropy alloy block and cut it into a rectangular block of 6mm×20mm×40mm;

Step 2: Homogenization annealing:

First turn on the tube furnace and preheat it to 1200°C; put the high-entropy alloy block into an alumina ceramic crucible and put it into the tube furnace; open the protective gas charging valve and fill the furnace tube with high-purity 99.999% pure Argon to complete the gas protection process; take out the sample after homogenization annealing for 24 hours, and cool it down to room temperature rapidly.

Step Three: Rolling:

The rolling mill was started, and the high-entropy alloy block after homogenization annealing was rolled at room temperature, and the thickness of the sample was rolled from 6mm to 0.6mm.

Step 4: Recrystallization annealing:

Cut the high-entropy alloy obtained in step 3 into a rectangular plate of 0.6mm×20mm×40mm; turn on the tube furnace and preheat it to 800°C; put the high-entropy alloy block into an alumina ceramic crucible and put it into the tube furnace ; Open the protective gas inflation valve, fill the furnace tube with high-purity argon gas with a purity of 99.999%, and complete the gas protection process; take out the sample after 4 hours of recrystallization annealing, and quickly cool it to room temperature.

Experimental test analysis:

Fig. 4 is a photo of a high-entropy alloy sample with a copper-containing AlCoCrFeNi eutectic composition prepared in Example 2 and subjected to recrystallization annealing at 800°C after stretching.

The deformation heat-treated high-entropy alloy plate annealed at 800 °C prepared in this example was used as a test sample for experimental inspection. According to the tensile test results in Figure 5, it can be seen that the tensile strength of the original cast alloy is 950.0 MPa, and the elongation at break is 950.0 MPa. Compared with 16.0%, the tensile strength of the heat-treated high-entropy alloy sheet annealed at 800°C increased to 1406.0MPa, and the elongation at break increased to 24.3%.

Comparative example 1

A deformation heat treatment method for a copper-containing AlCoCrFeNi eutectic cast high-entropy alloy improves the tensile strength of the Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 high-entropy alloy but greatly reduces the elongation.

The deformation heat treatment method is as follows:

Step 1: Sample pretreatment:

Clean the as-cast Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 high-entropy alloy block and cut it into a rectangular block of 6mm×20mm×40mm;

Step 2: Homogenization annealing:

First turn on the tube furnace and preheat it to 1150°C; put the high-entropy alloy block into an alumina ceramic crucible and put it into the tube furnace; open the protective gas charging valve and fill the furnace tube with high-purity 99.999% pure Argon to complete the gas protection process; take out the sample after homogenization annealing for 4 hours, and quickly cool to room temperature.

Step Three: Rolling:

The rolling mill was started, and the high-entropy alloy block after homogenization annealing was rolled at room temperature, and the thickness of the sample was rolled from 6 mm to 0.6 mm.

Step 4: Recrystallization annealing:

Cut the high-entropy alloy obtained in step 3 into a rectangular plate of 0.6mm×20mm×40mm; turn on the tube furnace and preheat it to 450°C; put the high-entropy alloy block into an alumina ceramic crucible and put it into the tube furnace ; Open the protective gas inflation valve, fill the furnace tube with high-purity argon gas with a purity of 99.999%, and complete the gas protection process; take out the sample after 4 hours of recrystallization annealing, and quickly cool it to room temperature.

Experimental test analysis:

Fig. 6 is a photo of a high-entropy alloy sample with a copper-containing AlCoCrFeNi eutectic composition prepared in Comparative Example 1 and annealed at 450°C after stretching.

The deformation heat-treated high-entropy alloy plate annealed at 450 °C prepared in this comparative example was used as a test sample for experimental inspection. According to the tensile test results in Figure 7, it can be seen that the tensile strength of the original cast alloy is 950.0 MPa, and the elongation at break is 950.0 MPa. Compared with 16.0%, the tensile strength of the heat-treated high-entropy alloy plate annealed at 450℃ increased to 1833.1MPa, but the elongation at break decreased to 4.2%;

From the EBSD-ipf diagram in Figure 8, it can be seen that the structure of the high-entropy alloy sheet annealed at 450 °C is a non-uniformly distributed shear band structure, not a bimodal structure.

Comparative example 2

A deformation heat treatment method for a copper-containing AlCoCrFeNi eutectic cast high-entropy alloy, which greatly increases the tensile strength of the Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 high-entropy alloy but decreases the elongation.

The deformation heat treatment method is as follows:

Step 1: Sample pretreatment:

Clean the as-cast Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 high-entropy alloy block and cut it into a rectangular block of 6mm×20mm×40mm;

Step 2: Homogenization annealing:

First turn on the tube furnace and preheat it to 1150°C; put the high-entropy alloy block into an alumina ceramic crucible and put it into the tube furnace; open the protective gas charging valve and fill the furnace tube with high-purity 99.999% pure Argon, to complete the gas protection process, the sample was taken out after 4 hours, and rapidly cooled to room temperature.

Step Three: Rolling:

The rolling mill was started, and the high-entropy alloy block after homogenization annealing was rolled at room temperature, and the thickness of the sample was rolled from 6 mm to 0.6 mm.

Step 4: Recrystallization annealing:

Cut the high-entropy alloy obtained in step 3 into a rectangular plate of 0.6mm×20mm×40mm; turn on the tube furnace and preheat it to 550°C; put the high-entropy alloy block into an alumina ceramic crucible and put it into the tube furnace ; Open the protective gas inflation valve, fill the furnace tube with high-purity argon gas with a purity of 99.999%, and complete the gas protection process; take out the sample after 4 hours of recrystallization annealing, and quickly cool it to room temperature.

Experimental test analysis:

Fig. 9 is a photo of a high-entropy alloy sample with a copper-containing AlCoCrFeNi eutectic composition prepared in Comparative Example 2 and annealed at 550°C after stretching.

The deformation heat-treated high-entropy alloy plate annealed at 550 °C prepared in this comparative example was used as a test sample for experimental inspection. According to the tensile test results in Figure 10, it can be seen that the tensile strength of the original cast alloy is 950.0 MPa, and the elongation at break is 950.0 MPa. Compared with 16.0, the tensile strength of the heat-treated high-entropy alloy sheet annealed at 550 °C increased to 2069.5 MPa, but the elongation at break decreased to 7.8%.

The foregoing embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form and in essence. It should be pointed out that those of ordinary skill in the art will also be able to make Several improvements and supplements should also be considered as the protection scope of the present invention.

Claims (10)

1. A method for simultaneously promoting copper-containing AlCoCrFeNi eutectic composition cast high-entropy alloy strength and plasticity, is characterized in that, comprises the following steps: Cutting the cast high-entropy alloy with copper-containing AlCoCrFeNi eutectic composition to obtain a rectangular block; performing homogenization annealing on the rectangular block to obtain an annealed material; The annealed material is sequentially subjected to rolling and recrystallization annealing, and the temperature of the recrystallization annealing is 600-850°C. 2 . The method according to claim 1 , characterized in that, the temperature of the homogenization annealing is 1000-1200° C. and the time is 4-48 hours. 3. The method according to claim 1, characterized in that both the homogenization annealing and the recrystallization annealing are performed in an inert protective gas. 4. The method according to claim 1, characterized in that the rolling deformation is 75%-95%. 5. The method according to claim 1, characterized in that, the recrystallization annealing time is 3-8 hours. 6 . The method according to claim 5 , characterized in that, the temperature of the recrystallization annealing is 700-800° C. and the time is 4-6 hours. 7. The method according to claim 1, further comprising cooling after the homogenization annealing. 8. The method according to claim 1, characterized in that the thickness of the rectangular block is greater than 6mm and not more than 1/2 of the width of the rectangular block. 9 . The method according to claim 1 , wherein the composition of the copper-containing AlCoCrFeNi eutectic composition cast high-entropy alloy is Al _7.3 Co _21.4 Cr _10.6 Ti _4.9 Fe _21.4 Ni _31.9 Cu _2.5 . 10. The copper-containing AlCoCrFeNi eutectic composition high-entropy alloy obtained by the method according to any one of claims 1 to 9, characterized in that the tensile strength of the copper-containing AlCoCrFeNi eutectic composition high-entropy alloy is 1406.0-1729.2MPa , The elongation is 22.6% to 24.3%.

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