SiC particle-induced strengthening high-strength high-plasticity eutectic high-entropy alloy and preparation method thereof

Abstract

The application relates to the field of metal structural materials, and specifically discloses a SiC particle-induced strengthening high-strength high-plasticity eutectic high-entropy alloy, which is characterized by comprising the following components: Fe 13at%-20at%, Co 13at%-20at%, Cr 13at%-20at%, Al 13at%-20at%, Ni 28at%-35at%, SiC 3wt%-10wt%, and inevitable impurities. The alloy is prepared by a magnetic suspension induction melting technology. The SiC particle-induced strengthening high-strength high-plasticity eutectic high-entropy alloy disclosed by the application is composed of face-centered cubic phase (FCC) and body-centered cubic phase (BCC). The tensile strength of the alloy at room temperature can reach 1018 MPa, the yield strength can reach 407 MPa, the elongation after fracture is about 18%, and the density is relatively low, about 7.42 g / cm 3 . In addition, the alloy has excellent mechanical properties such as tensile strength, yield strength and plasticity at room temperature and high temperature.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal structural materials, and particularly relates to a SiC particle-induced high-strength high-plasticity eutectic high-entropy alloy and a preparation method thereof. BACKGROUND

[0002] With the rapid development of the fields of aviation, aerospace, nuclear industry, automobile, chemical industry, rail transit, etc., higher requirements are put forward for the comprehensive performance and lightweight of components such as turbine discs, cladding, heat exchangers, and tail nozzles. In the prior art, nickel-based, cobalt-based, titanium alloys, and steels are the most widely used non-ferrous and ferrous metals. However, there are problems such as high density (nickel-based, cobalt-based, and steel) and relatively low strength (titanium alloy). In order to meet the requirements of the rapid development of advanced devices for the comprehensive performance of materials, new materials need to be developed.

[0003] High-entropy alloy (HEA) is a new multi-principal element alloy material composed of five or more metal elements with equal or nearly equal molar fractions, has a wide composition design space, and has excellent comprehensive performance due to its unique structure. The most studied high-entropy alloys are 3d transition series high-entropy alloys (TM HEAs) and refractory series high-entropy alloys (RHEAs). The 3d transition series high-entropy alloy is composed of transition elements such as Fe, Cr, Co, Ni, and Al. Through reasonable composition design, a eutectic high-entropy alloy mainly composed of eutectic structure can be formed. This series of high-temperature high-entropy alloys has the advantages of low density, good casting performance, good corrosion resistance and room temperature mechanical properties, excellent processing performance, etc., and becomes an ideal material that can replace traditional non-ferrous and ferrous metals.

[0004] However, although the FeCrCo series eutectic high-entropy alloy has excellent comprehensive performance, its strength and plasticity are not outstanding, and it does not have obvious advantages in strength and plasticity compared with traditional metal materials. Adding SiC particles to the alloy is one of the methods to improve the strength of the metal matrix composite. However, after adding SiC particles, the strength of the alloy is improved, but the plasticity is significantly reduced. The difficulty in simultaneously improving the strength and plasticity has become a major factor restricting the widespread use of eutectic high-entropy alloys. SUMMARY

[0005] In view of the problems in the prior art, the application provides a SiC particle-induced high-strength high-plasticity eutectic high-entropy alloy and a preparation method thereof, which specifically includes the following contents:

[0006] A SiC particle induced high-strength high-ductility eutectic high-entropy alloy, characterized in that it comprises the following components: Fe 13at% to 20at%, Co 13at% to 20at%, Cr 13at% to 20at%, Al 13at% to 20at%, Ni 28at% to 35at%, SiC 3wt% to 10wt%, and inevitable impurities. The batching method is as follows: first, prepare the raw materials of metal elements according to the atomic percentage ratio, and then add SiC according to the mass ratio.

[0007] Preferably, it comprises the following components: Fe 15at% to 18at%, Co 15at% to 18at%, Cr 15at% to 18at%, Al 15at% to 18at%, Ni 30at% to 33at%, SiC 5wt% to 8wt%, and inevitable impurities. Specifically, the content of Fe can be 15at%, 16at%, 17at%, 18at%, etc.; the content of Co can be 15at%, 16at%, 17at%, 18at%, etc.; the content of Cr can be 15at%, 16at%, 17at%, 18at%, etc.; the content of Al can be 15at%, 16at%, 17at%, 18at%, etc.; the content of Ni can be 30at%, 31at%, 32at%, 32.5at%, 33at%, etc.; and the content of SiC can be 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, etc.

[0008] Preferably, the high-strength high-ductility eutectic high-entropy alloy does not contain SiC particles, and the microstructure of the high-strength eutectic high-entropy alloy is composed of face-centered cubic phase FCC and body-centered cubic phase BCC, and the volume fraction of FCC phase is greater than that of BCC phase.

[0009] Preferably, the high-strength high-ductility eutectic high-entropy alloy containing SiC particles is prepared by magnetic levitation induction melting technology, vacuum arc melting technology, or electron beam melting technology.

[0010] A preparation method of a SiC particle induced high-strength high-ductility eutectic high-entropy alloy, wherein alloy raw materials are melted in a protective atmosphere with a pressure of 5×10 -3 MPa to 1×10 -2 MPa by using magnetic levitation induction melting technology, vacuum arc melting technology, or electron beam melting technology. The alloy raw materials comprise the following components: Fe 13at% to 20at%, Co 13at% to 20at%, Cr 13at% to 20at%, Al 13at% to 20at%, Ni 28at% to 35at%, SiC 3wt% to 10wt%, and inevitable impurities. Specifically, the melting pressure can be 5×10-3 MPa, 6×10 -3 MPa, 7×10 - 3 MPa, 8×10 -3 MPa, 9×10 -3 MPa, 1×10 -2 MPa, etc. Specifically, in the alloy raw materials: Fe content can be 13at%, 14at%, 15at%, 16at%, 18at%, 19at%, 20at%, etc.; Co content can be 13at%, 14at%, 15at%, 16at%, 18at%, 19at%, 20at%, etc.; Cr content can be 13at%, 14at%, 15at%, 16at%, 18at%, 19at%, 20at%, etc.; Al content can be 13at%, 14at%, 15at%, 16at%, 18at%, 19at%, 20at%, etc.; Ni content can be 28at%, 29at%, 30at%, 31at%, 32at%, 34at%, 35at%, etc.; SiC content can be 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, etc.

[0011] Preferably, the alloy raw materials need to be ground to remove the oxide layer on the surface of each raw material before melting, and the ground raw materials are ultrasonically cleaned in industrial grade ethanol for 20 min to 25 min; the protective gas is high-purity argon.

[0012] Preferably, the SiC particle size in the alloy raw material is 20-80μm, specifically 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 60μm, 70μm, 80μm, etc.

[0013] Preferably, the specific method for melting using magnetic levitation induction melting technology is as follows: first, the alloy raw material is placed in a magnetic levitation induction furnace, and a vacuum is drawn to a vacuum degree of 3×10⁻⁶. -3 Pa ~ 5 × 10 -3 Pa (e.g., 3.2 × 10⁻⁶) -3 Pa, 3.5 × 10 - 3 Pa, 4×10 -3 Pa, 4.5 × 10 -3 After (Pa, etc.), protective gas is introduced to maintain the furnace pressure at 5×10⁻⁶. -3 MPa ~ 1×10 -2 MPa (e.g. 6×10) -3 MPa, 7×10 -3 MPa, 8×10 -3 MPa, 9×10-3 MPa or the like); then the alloy raw material in the magnetic suspension induction furnace is melted, the melting current is 300A-450A (for example, 330A, 350A, 380A, 390A, 400A, 425A or the like), after the alloy raw material is completely melted into a liquid state, the melting is maintained for 2-5 minutes (for example, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or the like), the alloy solution is stirred by electromagnetic induction, and the SiC-induced high-strength high-plasticity eutectic high-entropy alloy is obtained after cooling.

[0014] Preferably, the specific method of melting by using the vacuum arc melting technology is as follows: first, the alloy raw material is placed in a vacuum arc furnace, vacuum is extracted to a vacuum degree of 3x10 -3 Pa-5x10 -3 Pa (for example, 3.2x10 -3 Pa, 3.5x10 -3 Pa, 4x10 -3 Pa, 4.5x10 -3 Pa or the like), the starting arc current is controlled to be 150A-250A (for example, 160A, 170A, 180A, 190A, 200A, 225A or the like), the melting current is 300A-450A (for example, 330A, 350A, 380A, 390A, 400A, 425A or the like), after the alloy raw material is completely melted into a liquid state, the melting is maintained for 2-5 minutes (for example, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or the like), and the alloy ingot is obtained after cooling; the obtained alloy ingot is flipped and repeated melting for at least 5 times (for example, 6 times, 8 times, 10 times, 15 times, 20 times or the like), and the SiC-induced high-strength high-plasticity eutectic high-entropy alloy is obtained.

[0015] Preferably, the specific method of melting by using the electron beam melting technology is as follows: first, the alloy raw material is placed in an electron beam furnace, vacuum is extracted to a vacuum degree of 3x10 3 Pa-5x10 -3 Pa (for example, 3.2x10 -3 Pa, 3.5x10 -3 Pa, 4x10 -3 Pa, 4.5x10 -3 Pa or the like), the power is 80-120kw (for example, 90kw, 100kw, 105kw, 108kw, 110kw or the like), after the alloy raw material is completely melted into a liquid state, the melting is maintained for 2-5 minutes (for example, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or the like), and the alloy ingot is obtained after cooling; the melting is repeated for at least 3 times, and the SiC-induced high-strength high-plasticity eutectic high-entropy alloy is obtained.

[0016] Advantages of the present application:

[0017] (1) The SiC-induced high-strength high-plasticity eutectic high-entropy alloy disclosed by the present application is composed of face-centered cubic phase (FCC) and body-centered cubic phase (BCC). The tensile strength of the alloy disclosed by the present application can reach 1018 MPa, the yield strength can reach 407 MPa, the elongation after fracture is about 18%, and the density is relatively low, about 7.42 g / cm 3 In addition, the high-entropy alloy disclosed by the present application has very excellent high-temperature performance and can still maintain excellent strength and plasticity in a high-temperature environment, and is a promising high-temperature structural material. It has been verified by experiments that the alloy disclosed by the present application has excellent mechanical properties such as tensile strength, yield strength and plasticity at room temperature and high temperature, as shown in Table 1.

[0018] (2) The alloy prepared by the present application with Fe 13at%~20at%, Co 13at%~20at%, Cr 13at%~20at%, Al 13at%~20at%, and Ni 28at%~35at% is a eutectic high-entropy alloy, which has good fluidity, i.e. good casting performance, and can effectively avoid casting defects in the alloy. The SiC particles of micron grade are added to the SiC-induced high-strength high-plasticity eutectic high-entropy alloy disclosed by the present application to promote the generation of FCC phase, so that the strength of the alloy is not decreased while the plasticity of the alloy material is improved.

[0019] (3) The SiC particles added by the present application do not exist in the alloy finally. Although SiC as a strengthening phase can improve the strength of the alloy, it will significantly reduce the plasticity of the alloy. The present application takes advantage of the low density of SiC and adds SiC particles with lighter density to the alloy, and the alloy raw materials are melted by using magnetic suspension induction melting technology, vacuum arc melting technology or electron beam melting technology in a protective atmosphere with a pressure of 5×10 -3 MPa~1×10 -2 MPa. During the cooling process of the liquid alloy, the SiC particles with lighter density float to the surface of the alloy, and there are no large amounts of SiC particles in the alloy, so that the strength of the alloy is improved while the plasticity is not decreased. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 XRD pattern of the alloy prepared in Example 1;

[0021] Figure 2 Microscopic morphology of the alloy prepared in Example 1;

[0022] Figure 3 XRD pattern of the alloy prepared in Example 3;

[0023] Figure 4 Microstructure of the alloy prepared for Example 3;

[0024] Figure 5 Tensile property diagram of the alloy prepared for Example 1;

[0025] Figure 6 Tensile property diagram of the alloy prepared for Example 3;

[0026] Figure 7 Microstructure of the alloy prepared for Example 4; DETAILED DESCRIPTION

[0027] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments. The examples shown below do not limit the invention described in the claims in any way. In addition, the entire content of the configuration represented by the following examples is not limited to what is necessary as a solution to the invention described in the claims. Figures 1-7 The present application will be described in detail below with reference to the accompanying drawings and specific embodiments. The examples shown below do not limit the invention described in the claims in any way. In addition, the entire content of the configuration represented by the following examples is not limited to what is necessary as a solution to the invention described in the claims.

[0028] Example 1

[0029] A SiC particle-induced strengthening high-strength high-ductility eutectic high-entropy alloy based on SiC particles, comprising Fe, Co, Cr, Ni, Al elements and SiC particles, the alloy composition is: Fe 16.5at%, Co 16.5at%, Cr 16.5at%, Al 16.5at%, Ni 34at%, SiC 0wt% and inevitable impurities.

[0030] A preparation method of a SiC particle-induced strengthening high-strength high-ductility eutectic high-entropy alloy, the specific steps are as follows:

[0031] (1) Select Fe, Co, Cr, Ni, Al with purity higher than 99.5% as metallurgical raw materials, polish the oxide skin on the surface of the metallurgical raw materials with sandpaper, and put them into industrial-grade ethanol for ultrasonic cleaning for 20 min, then dry them, and weigh the raw material components according to the atomic fractions Fe 16.5at%, Co 16.5at%, Cr 16.5at%, Al 16.5at%, Ni 34at% and inevitable impurities;

[0032] (2) Put the raw materials into a magnetic suspension induction furnace, then vacuumize to a vacuum degree of 3x10 -3 ~ 5x10 -3 Pa, fill high-purity argon to keep the gas pressure in the furnace at 5x10 -3 MPa;

[0033] (3) Alloy smelting is performed on the raw materials in the magnetic suspension induction furnace, the smelting current is 300 A, after the raw materials in the copper crucible are completely melted into a liquid state, the smelting is maintained for 4 min, and the alloy ingot is obtained after cooling;

[0034] (4) The alloy solution obtained in step (3) is stirred by electromagnetic induction, and step (3) is repeated to obtain a high-strength high-plasticity eutectic high-entropy alloy;

[0035] (5) The alloy treated in step (4) is analyzed by XRD, and it is found that the alloy is composed of FCC and BCC phases, Figure 1 as shown in the figure.

[0036] (6) The alloy treated in step (4) is analyzed by SEM morphology analysis, and it is found that the white contrast in the alloy is the FCC phase, and the black contrast is the BCC phase, and the two phases exhibit eutectic organization characteristics, Figure 2 as shown in the figure.

[0037] (7) The alloy treated in step (4) is subjected to room temperature and high temperature tensile test, and the results are shown in Table 1. The tensile strength of the alloy at room temperature is 964 MPa, the yield strength is 581 MPa, and the elongation after fracture is 9.5%; the tensile strength at 650℃ is 502 MPa, the yield strength is 304 MPa, and the elongation after fracture is 7.5%; the tensile strength at 750℃ is 361 MPa, the yield strength is 202 MPa, and the elongation after fracture is 10.5%; the tensile strength at 850℃ is 156 MPa, the yield strength is 71 MPa, and the elongation after fracture is 34.5%, as Figure 5 shown in the figure.

[0038] Example 2

[0039] A high-strength high-plasticity eutectic high-entropy alloy based on SiC particle induced strengthening, comprising Fe, Co, Cr, Ni, Al elements and SiC particles, the alloy composition is: Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at%, SiC 8wt% and unavoidable impurities.

[0040] A high-strength high-plasticity eutectic high-entropy alloy, the specific preparation method is as follows:

[0041] (1) Select Fe, Co, Cr, Ni and Al with purity higher than 99.5% as metallurgical raw materials, polish the oxide skin on the surface of the metallurgical raw materials with sandpaper, and ultrasonic clean in industrial grade ethanol for 20 min, then dry, and weigh the raw material components according to the atomic fraction Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at% and 50μm size SiC 8wt% and unavoidable impurities;

[0042] (2) Put the raw materials into a magnetic suspension induction furnace, then vacuumize to a vacuum degree of 4×10 -3 Pa, fill high-purity argon to keep the gas pressure in the furnace at 1×10-2 MPa;

[0043] (3) Alloy smelting is performed on the raw material in the magnetic suspension induction furnace, smelting current is 450 A, after the raw material in the copper crucible is completely melted into a liquid state, smelting is maintained for 5 min, and an alloy ingot is obtained after cooling;

[0044] (4) The alloy solution obtained in step (3) is stirred by electromagnetic induction, and step (3) is repeated to obtain a high-strength high-plasticity eutectic high-entropy alloy, the alloy is mainly composed of an FCC phase and a BCC phase, and no obvious SiC particles are observed in the alloy;

[0045] (5) Room temperature and high-temperature tensile tests are performed on the alloy treated in step (4), the room temperature tensile strength of the alloy is 1120 MPa, the yield strength is 420 MPa, and the elongation after fracture is 20%; the tensile strength at 650 DEG C is 520 MPa, the yield strength is 460 MPa, and the elongation after fracture is 5%; the tensile strength at 750 DEG C is 370 MPa, the yield strength is 310 MPa, and the elongation after fracture is 7%; the tensile strength at 850 DEG C is 140 MPa, the yield strength is 120 MPa, and the elongation after fracture is 42%. After adding SiC particles, the strength and plasticity of the alloy at room temperature are improved.

[0046] Example 3

[0047] A high-strength high-plasticity eutectic high-entropy alloy based on SiC particle induced strengthening includes Fe, Co, Cr, Ni, Al elements and SiC particles, and the alloy composition is: Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at%, SiC 6wt% and inevitable impurities.

[0048] A high-strength high-plasticity eutectic high-entropy alloy based on SiC particle induced strengthening disclosed by the application is prepared by the following specific method:

[0049] (1) Fe, Co, Cr, Ni and Al with a purity higher than 99.5% are selected as metallurgical raw materials, the oxide skin on the surface of the metallurgical raw materials is polished with sandpaper, and then the metallurgical raw materials are ultrasonically cleaned in industrial-grade ethanol for 20 min, and after drying, the raw material components are weighed according to the atomic fractions Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at% and 50μm-sized SiC 6wt% and inevitable impurities;

[0050] (2) The raw materials are placed in a magnetic suspension induction melting furnace, then vacuumized to a vacuum degree of 4×10 -3 Pa, high-purity argon is filled to keep the gas pressure in the furnace at 1×10 -2 MPa;

[0051] (3) The raw materials in the magnetic levitation induction furnace are alloyed and the melting current is 450A. After the raw materials in the copper crucible are completely melted into liquid, the melting is maintained for 5 minutes and then cooled to obtain alloy ingots.

[0052] (4) The alloy solution obtained in step (3) is stirred by electromagnetic induction, and step (3) is repeated to obtain a high-temperature high-entropy alloy. The XRD results of the obtained alloy are as follows: Figure 3 As can be seen, the alloy is mainly composed of FCC and BCC phases, and the peak intensity of the FCC phase is much higher than that of the BCC phase, proving that more FCC phase is formed. Combined with SEM microstructure (such as...), Figure 4 The alloy contains FCC (white) and BCC (black) phases, with the FCC phase accounting for a much higher proportion than the BCC phase. No SiC particles were observed in the alloy.

[0053] (5) The alloy treated in step (4) was subjected to room temperature and high temperature tensile tests. The results are shown in Table 1. The room temperature tensile strength of the alloy was 1018 MPa, the yield strength was 407 MPa, and the elongation after fracture was 18%; the 650℃ tensile strength was 501 MPa, the yield strength was 449 MPa, and the elongation after fracture was 3.5%; the 750℃ tensile strength was 358 MPa, the yield strength was 297 MPa, and the elongation after fracture was 5.5%; the 850℃ tensile strength was 129 MPa, the yield strength was 108 MPa, and the elongation after fracture was 40.5%; the density was 7.42 g / cm³. 3 ,like Figure 6 The addition of SiC particles improves both the room temperature strength and plasticity of the alloy, and also enhances its high-temperature yield strength.

[0054] Example 4

[0055] A high-strength, high-ductility, eutectic, high-entropy alloy based on SiC particle-induced strengthening includes Fe, Co, Cr, Ni, Al elements and SiC particles. The alloy composition is: Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at%, SiC 3wt%, and unavoidable impurities.

[0056] A high-strength, high-ductility, eutectic, high-entropy alloy based on SiC particle-induced strengthening is prepared by the following method:

[0057] (1) Select Fe, Co, Cr, Ni and Al with a purity higher than 99.5% as metallurgical raw materials. Polish the oxide skin on the surface of the metallurgical raw materials with sandpaper, and ultrasonically clean them in industrial grade ethanol for 20 minutes. After drying, weigh the raw material composition according to the atomic fractions of Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at%, and SiC with a size of 50μm 3wt%.

[0058] (2) Place the raw materials in the magnetic levitation induction furnace, and then evacuate to a vacuum degree of 4×10⁻⁶. -3 After Pa, high-purity argon gas is introduced to maintain the furnace pressure at 1×10⁻⁶. -2 MPa;

[0059] (3) The raw materials in the magnetic levitation induction furnace are alloyed and the melting current is 450A. After the raw materials in the copper crucible are completely melted into liquid, the melting is maintained for 5 minutes and then cooled to obtain alloy ingots.

[0060] (4) The alloy solution obtained in step (3) is stirred by electromagnetic induction, and step (3) is repeated to obtain a high-temperature high-entropy alloy. The SEM microstructure of the obtained alloy is shown in the figure (e.g., Figure 7 The alloy contains both white (FCC) and black (BCC) phases, with the FCC phase being significantly more abundant than the BCC phase. However, the proportion of FCC is less than that in Example 2, demonstrating that SiC promotes the formation of the FCC phase. Furthermore, the more SiC present, the greater the proportion of the FCC phase. No obvious SiC particles were observed in the alloy.

[0061] (5) The alloy has a room temperature tensile strength of 990 MPa, a yield strength of 395 MPa, and an elongation after fracture of 16%; a room temperature tensile strength of 490 MPa, a yield strength of 430 MPa, and an elongation after fracture of 2.5%; a room temperature tensile strength of 345 MPa, a yield strength of 285 MPa, and an elongation after fracture of 3.5%; and a room temperature tensile strength of 115 MPa, a yield strength of 97 MPa, and an elongation after fracture of 38.5%.

[0062] Table 1 shows a comparison of data from Examples 1-4. As can be seen from the data in Table 1, the alloy of the present invention (the alloy prepared in Example 2) exhibits superior comprehensive mechanical properties at high temperatures compared to the ordinary high-entropy alloy (the alloy prepared in Example 1). This demonstrates that the added SiC particles promote the formation of the FCC phase, and the alloy does not contain a large number of SiC particles. On the one hand, the FCC phase improves the alloy's plasticity; on the other hand, the absence of a large number of SiC particles in the alloy improves its strength without reducing its plasticity.

[0063] Example 5

[0064] A SiC particle induced strengthening high-strength high-plasticity eutectic high-entropy alloy based on SiC particles, comprising Fe, Co, Cr, Ni, Al elements and SiC particles, the alloy composition is: Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at%, SiC 6wt% and inevitable impurities.

[0065] A SiC particle induced strengthening high-strength high-plasticity eutectic high-entropy alloy based on SiC particles, comprising Fe, Co, Cr, Ni, Al elements and SiC particles, the alloy composition is: Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at%, SiC 6wt% and inevitable impurities.

[0066] (1) Select Fe, Co, Cr, Ni, Al with purity higher than 99.5% as metallurgical raw materials, polish the oxide skin on the surface of the metallurgical raw materials with sandpaper, and put them into industrial-grade ethanol for ultrasonic cleaning for 20 min, then dry them, and weigh the raw material components according to the atomic fractions Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at% and 50μm size SiC 6wt% and inevitable impurities;

[0067] (2) Put the raw materials into an electron beam melting furnace, then vacuumize to a vacuum degree of 4×10 -3 Pa;

[0068] (3) Alloy smelting is performed on the raw materials in the electron beam melting furnace, the smelting power is 100kw, after the raw materials in the copper crucible are completely melted into a liquid state, the smelting is maintained for 5 min, and the alloy ingot is obtained after cooling;

[0069] (4) Repeat step (3) to obtain a high-temperature high-entropy alloy, the XRD results of the obtained alloy show that the alloy is mainly composed of FCC phase and BCC phase, and the FCC phase peak strength is much higher than that of the BCC phase, which proves that more FCC phase is generated, and no SiC particles are found in the alloy;

[0070] (5) Room temperature tensile test is performed on the alloy treated in step (4), and the results are shown in Table 1, the room temperature tensile strength of the alloy is 1000MPa, the yield strength is 400MPa, and the elongation after fracture is 16%; the tensile strength at 650℃ is 497MPa, the yield strength is 440MPa, and the elongation after fracture is 3.3%; the tensile strength at 750℃ is 350MPa, the yield strength is 290MPa, and the elongation after fracture is 5.3%; the tensile strength at 850℃ is 125MPa, the yield strength is 105MPa, and the elongation after fracture is 39%. After adding SiC particles, the room temperature strength and plasticity of the alloy are improved, and the high-temperature yield strength is also improved to a certain extent.

[0071] Example 6

[0072] A SiC particle induced strengthening high-strength high-plasticity eutectic high-entropy alloy, comprising Fe, Co, Cr, Ni, Al elements and SiC particles, the alloy composition is: Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at%, SiC 6wt% and inevitable impurities.

[0073] A SiC particle induced strengthening high-strength high-plasticity eutectic high-entropy alloy disclosed by the present application, the specific preparation method is as follows:

[0074] (1) Select Fe, Co, Cr, Ni and Al with purity higher than 99.5% as metallurgical raw materials, polish the oxide skin on the surface of the metallurgical raw materials with sandpaper, and put them into industrial-grade ethanol for ultrasonic cleaning for 20 min, and then dry them, and then weigh the raw material components according to the atomic fractions Fe 16.4at%, Co 16.4at%, Cr 16.4at%, Al 16.4at%, Ni 33at% and 50μm size SiC 6wt% and inevitable impurities;

[0075] (2) Put the raw materials into an arc melting furnace, and then vacuumize to a vacuum degree of 4×10 -3 Pa;

[0076] (3) Alloy smelting is performed on the raw materials in the arc melting furnace, the starting arc current is 200A, the smelting current is 450A, after the raw materials in the copper crucible are completely melted into a liquid state, the smelting is maintained for 5 min, and then the alloy ingot is obtained after cooling;

[0077] (4) Turn over the alloy ingot obtained in step (3), repeat step (3), and obtain a high-temperature high-entropy alloy, the XRD result of the obtained alloy shows that the alloy is mainly composed of FCC phase and BCC phase, and the peak strength of the FCC phase is much higher than that of the BCC phase, which proves that more FCC phase is generated, and no SiC particles are found in the alloy;

[0078] (5) The alloy treated in step (4) is subjected to room temperature tensile test, and the results are shown in Table 1, the room temperature tensile strength of the alloy is 1005MPa, the yield strength is 403MPa, and the elongation after fracture is 17%; the tensile strength at 650℃ is 499MPa, the yield strength is 442MPa, and the elongation after fracture is 3.4%; the tensile strength at 750℃ is 353MPa, the yield strength is 293MPa, and the elongation after fracture is 5.4%; the tensile strength at 850℃ is 128MPa, the yield strength is 106MPa, and the elongation after fracture is 40%. After adding SiC particles, the room temperature strength and plasticity of the alloy are improved, and the high-temperature yield strength is also improved to a certain extent.

[0079] Table 1 Performance test data table of the alloy prepared in examples 1-6

[0080]

[0081] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Numerous modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without the use of the inventive faculty. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-strength, high-ductility, eutectic, high-entropy alloy based on SiC particle-induced strengthening, characterized in that, The alloy raw material was subjected to a pressure of 5×10 -3 MPa ~ 1×10 -2 In a protective atmosphere of MPa, the alloy is smelted using magnetic levitation induction melting technology, vacuum arc melting technology, or electron beam melting technology. The alloy raw materials include the following components: Fe 13at%~20at%, Co 13at%~20at%, Cr 13at%~20at%, Al 13at%~20at%, Ni 28at%~35at%, SiC 3wt%~10wt%, with the balance being unavoidable impurities. The batching method is to first prepare the raw materials of the metal elements according to the atomic percentage ratio, and then add SiC according to the mass ratio. The SiC particle size in the alloy raw materials is 20-80μm. The resulting high-strength, high-plasticity, eutectic high-entropy alloy does not contain SiC particles. The microstructure of the high-strength, high-plasticity, eutectic high-entropy alloy consists of face-centered cubic (FCC) phase and body-centered cubic (BCC) phase, with the volume fraction of the FCC phase being greater than that of the BCC phase.

2. The method for preparing a high-strength, high-ductility, eutectic, high-entropy alloy based on SiC particle-induced strengthening according to claim 1, characterized in that, Before smelting, the alloy raw materials need to be polished to remove the oxide layer on the surface of each raw material, and the polished raw materials are placed in industrial-grade ethanol for ultrasonic cleaning for 20 to 25 minutes; the protective gas is high-purity argon.

3. A method for preparing a high-strength, high-ductility, eutectic, high-entropy alloy based on SiC particle-induced strengthening, as described in claim 1 or 2, characterized in that... The specific method for melting using magnetic levitation induction melting technology is as follows: First, the alloy raw material is placed in a magnetic levitation induction furnace, and a vacuum is drawn to a vacuum degree of 3×10⁻⁶. -3 Pa ~ 5 × 10 -3 After Pa, protective gas is introduced to maintain the furnace pressure at 5 × 10⁻⁶. -3 MPa ~ 1×10 -2 MPa; then the alloy raw materials in the magnetic levitation induction furnace are smelted at a smelting current of 300A to 450A. After the alloy raw materials are completely melted into a liquid state, the smelting is maintained for 2 to 5 minutes. The alloy liquid is stirred by electromagnetic induction and cooled to obtain the SiC particle-induced strengthened high-strength, high-plasticity eutectic high-entropy alloy.

4. A method for preparing a high-strength, high-ductility, eutectic, high-entropy alloy based on SiC particle-induced strengthening, as described in claim 1 or 2, characterized in that... The specific method for melting using vacuum arc melting technology is as follows: First, the alloy raw material is placed in a vacuum arc furnace, and a vacuum degree of 3×10⁻⁶ is drawn. -3 Pa ~ 5 × 10 -3 After Pa, the arc-starting current is controlled at 150A to 250A and the melting current is controlled at 300A to 450A. After the alloy raw material is completely melted into a liquid state, the melting is maintained for 2 to 5 minutes. After cooling, an alloy ingot is obtained. The obtained alloy ingot is flipped and the melting is repeated at least 5 times to obtain the SiC particle-induced strengthened high-strength, high-plasticity eutectic high-entropy alloy.

5. A method for preparing a high-strength, high-ductility, eutectic, high-entropy alloy based on SiC particle-induced strengthening, as described in claim 1 or 2, characterized in that... The specific method for melting using electron beam melting technology is as follows: First, the alloy raw material is placed in an electron beam furnace, and a vacuum degree of 3×10⁻⁶ is drawn. -3 Pa ~ 5 × 10 -3 After Pa, the power is 80-120kw. After the alloy raw material is completely melted into a liquid state, the melting is maintained for 2min-5min. After cooling, an alloy ingot is obtained. The melting is repeated at least 3 times to obtain the SiC particle-induced strengthened high-strength, high-plasticity eutectic high-entropy alloy.

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