Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The embodiment of the invention provides a nickel-based superalloy, which comprises the following elements in percentage by mass: 15.00 to 25.00 percent of Cr, 0.01 to 1.00 percent of Fe, 1.20 to 5.00 percent of W, 12.00 to 21.50 percent of Mo, 0.80 to 2.00 percent of Cu, and the balance of Ni.
The inventor improves the element composition of the nickel-based superalloy, so that the prepared nickel-based superalloy material is composed of gamma-Ni with excellent toughness and high temperature resistance, and the high temperature resistance, corrosion resistance and wear resistance of the material are effectively improved while the plasticity and toughness of the material are ensured.
Specifically, in the composition of the nickel-base superalloy, the elements have the following functions:
cr element is easy to generate a layer of compact passive film in a corrosive environment, and can play a role in protecting metal materials from further corrosion. And Mo has the function of stabilizing the Cr element passive film, so that the addition of a proper amount of Mo is beneficial to the stable existence of the passive film, and the corrosion resistance of the material is ensured. The W element plays a role in red hardness in a high-temperature environment, and ensures that the material still has high hardness in the friction and wear processes and the like. In addition, the Cu element can form an infinite solid solution in the Ni-based alloy, and the addition of the W element and the Cu element plays a role in solid solution strengthening on the Ni-based alloy and plays a great role in promoting the strength, the hardness, the corrosion resistance, the oxidation resistance and the high-temperature strength of the Ni-based alloy.
Since several elements are often inevitably introduced, but the effect is not great, the inventor further defines the composition, and the element composition is as follows: 0.001-0.010% of C, 0.01-0.10% of Mn, 0.01-0.10% of Si, 0.001-0.020% of P, 0.001-0.010% of S, 15.00-25.00% of Cr, 0.01-0.10% of Fe, 1.20-5.00% of W, 12.00-21.50% of Mo, 0.80-2.00% of Cu, 0.001-0.030% of O, 0.0001-0.001% of N and the balance of Ni.
To further enhance the overall performance of the material, the inventors have optimized the elemental composition, which in the preferred embodiment is: 0.003-0.009% of C, 0.01-0.04% of Mn, 0.03-0.08% of Si, 0.008-0.015% of P, 0.005-0.008% of S, 18.00-24.25% of Cr, 0.1-0.6% of Fe, 1.50-5.00% of W, 13.50-18.3% of Mo, 1.00-2.00% of Cu, 0-0.03% of O, 0-0.005% of N and the balance of Ni.
The embodiment of the invention provides a preparation method of a nickel-based superalloy, which comprises the steps of proportioning according to the element composition of a nickel-based superalloy material and smelting. The specific smelting method can adopt the existing process, and is not limited herein.
The nickel-based high-temperature alloy can be alloy powder or alloy parts, and the alloy parts are prepared by preparing the alloy powder by a conventional process and then preparing the alloy parts by an additive manufacturing method.
S1 preparation of nickel-based alloy powder
Further, the preparation of the nickel-based alloy powder comprises: the raw materials are mixed, then are crushed, smelted and granulated in sequence, and the crushed raw materials are smelted at high temperature and then are granulated to obtain the required powder.
Specifically, the metal raw materials are cast ingots with the purity of 99.9 percent as raw materials so as to ensure the accuracy of the burdening.
In some embodiments, the pulverization is performed by ball milling to a particle size of 10-180 μm to meet the smelting requirement. In the ball milling process, the ball milling rotating speed is controlled to be 400-800 r/min, the time is 20-40 h, and the ball material ratio is 5-8: 1.
Specifically, the ball milling rotation speed can be 400r/min, 500r/min, 600r/min, 700r/min, 800r/min and the like, the ball milling time can be 20h, 25h, 30h, 35h, 40h and the like, and the ball-to-material ratio can be 5:1, 6:1, 7:1, 8:1 and the like. The grinding ball can be made of Si3N4And the ball milling process is preferably carried out under an inert gas atmosphere (e.g., argon having a purity of 99.00 wt.%), which may be high purity argon having a purity of approximately 99.00 wt.%.
In some embodiments, the smelting is carried out at 1200-1600 ℃ for 60-80 min. Specifically, the melting temperature may be 1200 ℃, 1300 ℃, 1400 ℃, 1500 ℃, 1600 ℃ or the like, or may be any value between the above adjacent temperatures; the smelting time is 60min, 65min, 70min, 75min, 80min, etc., and can be any value between the adjacent time values.
In some embodiments, the granulation is spray granulated under an inert atmosphere (e.g., nitrogen with a purity of 99.00 wt.%), and the powder having a particle size in the range of 10-130 μm is screened to remove the oversize powder, which is suitable for laser additive manufacturing.
In some embodiments, drying the powder after granulation is further included, and the powder after drying is used for laser additive manufacturing. The drying temperature is 120-200 ℃, and the drying pressure is 120-200MPa, so as to effectively remove impurities. Specifically, the drying temperature may be 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, and the drying pressure may be 120MPa, 130MPa, 140MPa, 150MPa, 160MPa, 170MPa, 180MPa, 190MPa, 200MPa, or the like.
S2 preparation of parts
The prepared nickel-based alloy powder is prepared into parts by adopting a metal additive manufacturing mode, and the shapes and the sizes of the specific parts are not limited and can be set according to requirements. The metal additive manufacturing method can refer to the prior art, and the specific steps are not limited.
In the actual operation process, the method comprises the following steps: utilizing three-dimensional modeling software to establish a model, and then leading the model into an additive manufacturing system to generate a laser scanning path of the part; placing nickel-based alloy powder in a powder storage bin of a laser additive manufacturing system, and performing forming manufacturing on required parts by using the laser additive manufacturing system; the three-dimensional modeling software is selected from any one of UG, Solidworks, Pro/e and CATIA; the forming of the laser scanning path includes: by converting the information in the three-dimensional model into a plurality of slices and defining each slice as a cross-sectional layer of the part.
Specifically, the additive manufacturing process is selected from any one of Direct Metal Deposition (DMD), Direct Metal Laser Sintering (DMLS), laser near net shaping (LENS), Laser Metal Forming (LMF), Selective Laser Melting (SLM), and Selective Laser Sintering (SLS).
The features and properties of the present invention are described in further detail below with reference to examples.
Example 1
The embodiment provides a nickel-based superalloy, which comprises the following elements in percentage by mass: 22.68% of Cr, 0.57% of Fe, 3.89% of W, 16.10% of Mo, 1.67% of Cu and the balance of Ni.
The embodiment provides a preparation method of a nickel-based superalloy, which comprises the following steps:
(1) the raw materials were weighed according to the composition in the present example, and then ball-milled in a protective atmosphere filled with high-purity argon (99.00 wt.%), the ball-milling pot being a stainless steel pot, and the milling balls being silicon nitride balls (Si balls)3N4) The detailed parameters of ball milling are as follows: the ball milling speed is 500r/min, the time is 20h, and the ball-material ratio is 5: 1.
(2) Vacuum melting was performed by heating to 1500 ℃ under a vacuum atmosphere for 60 minutes and spray granulation was performed using high purity nitrogen gas having a purity of 99.00 wt.%.
(3) And putting the collected powder into a vacuum drying oven, vacuumizing until the pressure is 100MPa, heating to 120 ℃, heating at a rate of 80 ℃/min, preserving heat for 2h, carrying out vacuum drying, putting the dried nickel-based alloy powder into a vacuum bag, and vacuumizing for storage for later use.
(4) And establishing a three-dimensional model by using Solidworks software, then importing the three-dimensional model into Magics software for placing parts and setting a laser scanning sequence.
(5) And (4) pouring the powder in the step (3) into a powder storage bin of a Selective Laser Melting (SLM) additive manufacturing system, and waiting for Selective laser melting and forming.
(6) The method is characterized in that an EOS M290 system is used for forming and manufacturing a metallographic sample, a tensile sample, a friction wear sample and an electrochemical corrosion sample on powder, and the specific process parameters are as follows: the laser spot was 100 μm, the laser power was 260W, the layer thickness was 30 μm, the scanning pitch was 110 μm, and the scanning speed was 1000 mm/s.
Example 2
The embodiment provides a nickel-based superalloy, which comprises the following elements in percentage by mass: 0.001% of C, 0.01% of Mn, 0.01% of Si, 0.001% of P, 0.001% of S, 15.00% of Cr, 0.01% of Fe, 1.20% of W, 12.00% of Mo, 0.80% of Cu, 0.001% of O, 0.0001% of N and the balance of Ni.
This example provides a method for preparing a nickel-base superalloy, which comprises weighing the raw materials according to the components in this example, and referring to example 1.
After the contents of the elements in this example are minimized, the corrosion resistance is slightly reduced compared to example 1, and the weight is reduced by about 0.06% after soaking in 30% HCl solution for 96 hours, and the solution is greener than in example 1. The average microhardness is 298.5HV0.2(ii) a In the friction wear test, the wear rate is 10.96 multiplied by 10-4mm3V (N · m), the specific test conditions are: 500g of load, 200rpm of rotating speed, 188.5m of friction distance and 5mm of friction radius, and a grinding ball Si3N4. But the overall performance change is not very obvious and can still meet the actual industrial requirements.
Example 3
The embodiment provides a nickel-based superalloy, which comprises the following elements in percentage by mass: 0.010% of C, 0.10% of Mn, 0.10% of Si, 0.020% of P, 0.010% of S, 25.00% of Cr, 0.10% of Fe, 5.00% of W, 21.50% of Mo, 2.00% of Cu, 0.030% of O, 0.001% of N and the balance of Ni.
This example provides a method for preparing a nickel-base superalloy, which comprises weighing the raw materials according to the components in this example, and referring to example 1.
In the example, each element is the maximum value of the invention, and the corrosion resistance is obviously improved due to the sharp increase of Cr and Mo elements, the weight is reduced by about 0.012 percent after the Cr and Mo elements are soaked in 30 percent HCl solution for 96 hours, and the green color of the solution is not obviously changed compared with that in the example 1. The average microhardness is obviously improved due to the solid solution strengthening effect of the elements such as W, Mo and Cr, and the average value after 10 times of measurement is 358HV0.2(ii) a In the frictional wear test, the wear rate thereofA slight decrease of 5.38X 10 after 3 measurements-4mm3V (N · m), the specific test conditions are: 500g of load, 200rpm of rotating speed, 188.5m of friction distance and 5mm of friction radius, and a grinding ball Si3N4。
Comparative example 1
The difference from the embodiment 1 is that the nickel-based superalloy has the following element composition by mass percent: 22.68% of Cr, 0.57% of Fe, 15.00% of W, 16.10% of Mo, 1.67% of Cu and the balance of Ni.
Since the W element is an element having very excellent high-temperature red hardness, in order to further improve the strong hardness of the material under a high-temperature environment, a large amount of the W element was added in the comparative example, but a large amount of hollow powder was generated during the powder preparation and a cracked powder (as shown in fig. 4) was contained, and the powder had a low sphericity, and a large amount of satellite spheres and irregular ellipsoidal powder were present. Therefore, the performance of the powder does not reach the standard, the aim of the invention cannot be achieved, and the powder cannot be well applied to the field of laser additive manufacturing.
Comparative example 2
The difference from the embodiment 1 is that the nickel-based superalloy has the following element composition by mass percent: 22.68% of Cr, 0.57% of Fe, 3.89% of W, 16.10% of Mo, 20.00% of Cu and the balance of Ni.
Cu can form an infinite solid solution in the Ni-based alloy and can improve the toughness of the nickel-based alloy, and therefore, a large amount of Cu element is added in this comparative example. Although the dosage of Cu element is greatly increased, the solid solution strengthening effect of the Cu element has very limited improvement on the obdurability, and the average hardness is only increased to 318.5HV0.2And the elongation reduction is obvious and is only 12 percent. In addition, the corrosion resistance of the alloy in a reducing medium is extremely reduced, for example, the weight loss rate of the alloy after being soaked in a 30% HCl solution for 96 hours reaches 1%, and the color of the solution is changed into dark green. Therefore, the powder ingredients used in this comparative example are not suitable for use in this patent, taken together.
Test example 1
The SLM alloy test piece obtained in test example 1 was subjected to the test of mechanical properties and physical properties as shown in (a) in fig. 1. As can be seen from the figure, the prepared nickel-based alloy powder has high sphericity and the microstructure is mainly equiaxed crystal.
According to the GB/T19077-2016 standard, the particle size distribution measured by using an MS3000 laser particle size analyzer is shown in (b) in FIG. 1, the average particle size is 35.4 μm, and the range of the particle size of the common powder for selective laser melting is 13-53 μm is satisfied.
According to the GB/T1482-2010 standard, the powder flowability measured by using a JHY-1002 Hall flow meter is 14.4s/50g, and the requirement of the selective laser melting process is met.
Test example 2
The composition of the powder phase obtained in test example 1 and the phase of the laser selective fusion formed part are shown in FIG. 2, from which it can be seen that the material is mainly composed of the γ -Ni phase.
Testing the quality change at different temperatures and different mediums is shown in table 1, and the manufactured SLM nickel-based alloy material has excellent corrosion resistance in strong acid corrosive liquid and oxidizing corrosive mediums at different temperatures.
The stress-strain curve at room temperature (25 ℃) in stretching is shown in FIG. 3 (a), and the tensile strength is 708.8MPa, the yield strength is 510.9MPa, and the elongation is 23.2%; average microhardness of 315.3HV0.2(ii) a In the friction wear test, the wear rate is 6.27X 10-4mm3V (N · m), the specific test conditions are: 500g of load, 200rpm of rotating speed, 188.5m of friction distance and 5mm of friction radius, and a grinding ball Si3N4。
TABLE 1 Corrosion of SLM Nickel-based alloy parts in different etching solutions
In summary, the embodiments of the present invention provide a nickel-based superalloy, a preparation method and an application thereof, wherein the inventor improves the element composition and the dosage ratio of the nickel-based superalloy, so that the prepared alloy material is composed of γ -Ni with excellent toughness and good high temperature resistance, and the high temperature resistance, corrosion resistance and wear resistance of the material are effectively improved while the ductility and toughness of the material are ensured, so that the nickel-based superalloy is a special nickel-based alloy powder material suitable for laser additive manufacturing, and the material application scope in the additive manufacturing field is expanded.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.