High-strength, high-toughness and anti-oxidation vegetarized high-temperature alloy and preparation method thereof

Abstract

The invention relates to the field of high-temperature alloy design and manufacturing, in particular to a high-strength, high-toughness and anti-oxidation vegetarized high-temperature alloy and a preparation method thereof. The alloy consists of MCr / MCrAl (M = Ni, Co or a combination), Ti3SiC2 or Ti3AlC2 ceramic and Si, and is prepared by spark plasma sintering. The alloy comprises, by weight, 90-95% of an alloy matrix, 3-6% of ceramic and 2-5% of Si. Si regulates and controls current and temperature fields, so that carbides are transferred from a grain boundary to a grain, segregation is avoided, and strength and plasticity are improved. The prepared alloy has high density, high hardness, high yield strength and high oxidation resistance, the dependence on rare elements is reduced, the cost is reduced, and the alloy is suitable for manufacturing parts in high-temperature and high-load environments.

Description

Technical Field

[0001] The present invention belongs to the field of high-temperature alloy design and manufacturing, and specifically relates to a high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy and a preparation method thereof. Background Art

[0002] High-temperature alloys are widely used in advanced propulsion systems, such as turbine blades, high-temperature bearings, and bushings in jet engines, due to their excellent high-temperature mechanical strength, creep resistance, corrosion resistance, and fatigue resistance. With the development of aerospace technology and the continuous improvement of thrust-to-weight ratio, people have put forward higher and higher requirements for high-performance high-temperature alloys.

[0003] Typically, researchers add carbides such as TiC, SiC, WC, MoC, and NbC into the metal matrix to achieve dispersion strengthening. However, due to the poor interface bonding between the carbides and the matrix, and the tendency of carbides to segregate at the grain boundaries during sintering, the yield strength and elongation of the material decrease. Chinese patent CN 104862531 A, "Nano-silicon carbide particle-reinforced nickel-based composite materials and molten salt reactor core structures," discloses a silicon carbide-reinforced nickel-based high-temperature alloy material prepared by plasma sintering. After adding different amounts of silicon carbide, the alloy strength is improved to a certain extent; however, due to the poor bonding between the carbides and the matrix and the fact that the carbides are basically distributed at the grain boundaries, the strengthening effect is limited. After adding 1-3.5 wt% silicon carbide, the room temperature yield strength of the alloy is slightly greater than 300 MPa, which cannot meet the material's requirement for high yield strength. Chinese patent CN 115449659 A, "Oxide Dispersion Strengthened Nickel-Based Superalloys, Preparation Methods, and Applications thereof," discloses an oxide-strengthened nickel-based alloy manufactured by laser additive manufacturing. Laser additive manufacturing controls the in-situ formation of dispersed oxide particles from the reaction between metal and oxygen, improving the alloy's tensile strength to a certain extent. However, the overall effect is limited, with the alloy's room-temperature tensile strength below 950 MPa, failing to meet the comprehensive performance requirements of high-temperature alloys, including high mechanical strength, high corrosion resistance, and high fatigue resistance. U.S. Patent US 11814704 (B2), "High Strength Thermally Stable Nickel-Base Alloys," discloses a method for preparing a highly stable nickel-based superalloy. The mechanical properties of the nickel-based alloy are enhanced by alloying elements such as Al, Ti, Mo, Nb, W, and Co. Although the room-temperature yield strength reaches 655 MPa and the tensile strength reaches 1104 MPa, its high cost limits its widespread application and hinders the sustainable development of high-temperature alloy materials. Therefore, there is an urgent need to develop a new type of high-temperature alloy with high strength, high toughness and excellent oxidation resistance to overcome the problems of carbide segregation, poor interface bonding and excessive dependence on rare and expensive alloying elements in the existing technology, so as to meet the needs of national defense and national industry for high-performance and low-cost high-temperature alloys. Summary of the Invention

[0004] This invention addresses the problem of carbides segregating at grain boundaries during the preparation of existing high-temperature alloys, resulting in poor interfacial bonding with the matrix. This invention proposes a high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy and its preparation method. Through specific composition design and process optimization, uniform distribution of carbides within the grains is achieved, significantly improving the material's overall performance.

[0005] The technical solution of the present invention is: A high-strength, high-toughness, oxidation-resistant, elemental high-temperature alloy, comprising the following components by weight: High temperature alloy matrix powder 90-95%; Ti3SiC2 or Ti3AlC2 ternary layered carbide ceramic powder 3-6%; Si powder 2-5%; The high-temperature alloy matrix is MCr or MCrAl, wherein M is Ni, Co or any combination thereof, the mass percentage of Cr is 15-30%, and the mass percentage of Al is ≤5%.

[0006] Furthermore, in the above-mentioned high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy, the particle size of the high-temperature alloy powder is 30 to 100 μm, the particle size of the Ti3SiC2 or Ti3AlC2 ternary layered carbide ceramic powder is ≤3 μm, and the particle size of the Si powder is ≤2 μm.

[0007] Furthermore, the above-mentioned high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy has the following performance indicators: density ≥99%; hardness ≥400HV; yield strength ≥1100MPa; tensile strength ≥1400MPa; elongation ≥6%; in the temperature range of 200-900°C, the oxidation resistance level of the alloy is fully oxidation-resistant.

[0008] The method for preparing the above-mentioned high-strength, high-toughness, and oxidation-resistant elemental high-temperature alloy comprises the following steps: (1) Powder mixing: Place high-temperature alloy powder, Ti3SiC2 or Ti3AlC2 ternary layered carbide ceramic powder, and Si powder in a planetary ball mill according to the ratio and perform high-energy ball milling. The main disc speed is 300-400 rpm and the ball milling time is 5-50 hours to obtain a uniformly mixed composite powder. (2) Pre-pressing: The composite powder obtained in step (1) is placed into a graphite grinding tool and flattened, and then pre-pressed using a cold press; (3) Spark plasma sintering: The graphite grinding tool loaded with the composite powder in step (2) is placed in the furnace chamber of the spark plasma sintering equipment for sintering. After the sintering is completed, the alloy is obtained by cooling the furnace.

[0009] Furthermore, in the above-mentioned method for preparing the high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy, the ball mill and the mixed material used in the planetary ball mill in step (1) are both made of cemented carbide, the ball-to-material ratio is 10:1, and argon is introduced as a protective gas.

[0010] Furthermore, in the method for preparing the above-mentioned high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy, in step (2), a cold press is used to pre-press the alloy at a rate of 10 MPa / min to 20 MPa, which is maintained for 10 minutes and then unloaded.

[0011] Furthermore, in the method for preparing the above-mentioned high-strength, high-toughness and oxidation-resistant primed high-temperature alloy, the process parameters of the spark plasma sintering are: the vacuum degree is less than 1×10 -2 Pa; sintering temperature is 1100-1200°C; heating rate is 40-60°C / min; sintering pressure is 30-50 MPa; holding time is 10-30 min.

[0012] Furthermore, in the above-mentioned method for preparing the high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy, the Ti3SiC2 or Ti3AlC2 ternary layered carbide ceramic powder decomposes during the sintering process to generate nano-TiC clusters, and some of the nano-TiC is distributed in the crystal.

[0013] In particular, the design core of the present invention is to introduce Si particles to regulate the current size and temperature field distribution in the local area of the alloy during the spark plasma sintering process. During the sintering process, Ti3SiC2 decomposes to form fine nano-TiC clusters, and some nano-TiC can flow into the crystal, thereby avoiding the segregation of carbides at the grain boundaries in traditional powder metallurgy methods. Due to its semiconductor properties, Si particles regulate the local current and temperature field during the spark plasma sintering process, causing the alloy particle boundaries to melt, and using nano-carbides as heterogeneous points. After solidification, the nano-carbides are transferred from the original distribution along the grain boundaries to the crystal, and form a coherent interface with the alloy matrix. This transfer not only improves the dispersion strengthening effect, but also enhances the fine grain strengthening effect, thereby significantly improving the comprehensive mechanical properties of the material. Furthermore, the present invention reduces the dependence on rare and expensive alloying elements by rationally designing the ratio of the matrix to the reinforcing phase, reduces material costs, and improves material utilization.

[0014] Advantages and beneficial effects of the present invention: 1. The present invention uses MCr or MCrAl as the alloy matrix, which has the advantages of high toughness, excellent thermal stability, corrosion resistance, etc. After adding Ti3SiC2 or Ti3AlC2 ternary layered carbide ceramic powder, due to its layered structure, it will decompose during the high-temperature sintering process to generate fine nano-TiC clusters, which greatly reduces the size of the carbide and improves the mechanical properties of the material.

[0015] 2. The spark plasma sintering method of the present invention can sinter and prepare high-density nanomaterials. The alloy prepared by this sintering method can minimize the high-temperature growth of grains. At the same time, the local high temperature generated during the discharge process causes local melting of the alloy powder particles, which promotes the intracrystalline flow of carbide ceramics. During the solidification process of the alloy, carbides serve as heterogeneous points, achieving good interface bonding between ceramics and metals.

[0016] 3. In the present invention, by introducing Si, the current size and temperature field in the local area of the alloy can be controlled during the spark plasma sintering process, so that more areas of the alloy are melted during the sintering process, which promotes the intracrystalline flow of nanocarbides and inhibits their segregation at the grain boundaries. At the same time, Si can occupy the metal lattice, promote the intracrystalline precipitation of carbides, increase the total content of carbides in the crystals, improve the dispersion strengthening and fine grain strengthening effects, greatly improve the material strength while maintaining good plasticity, reduce the dependence of high-temperature alloy materials on rare and expensive alloying elements, improve material utilization efficiency and reduce costs.

[0017] 3. The material of the present invention exhibits complete oxidation resistance in the temperature range of 200-900°C, meeting the application requirements in high-temperature environments and having a wide range of uses in engineering machinery, nuclear power industry, aerospace and other fields.

[0018] 4. The process parameters in the preparation process of the material of the present invention are easy to control and highly feasible, the experimental method is simple and novel, and is suitable for large-scale production.

[0019] 5. The metal powder used in the present invention is moderately priced and easily available. The material properties can be controlled through simple process adjustments, reducing dependence on rare and expensive alloying elements, which is in line with the sustainable development trend of high-temperature alloy materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The morphology of the material after sintering is shown in Example 1, which uses NiCr alloy powder as the matrix and Si and Ti3SiC2 powder as the added phase; Figure 2 This is the morphology of the material after sintering in Comparative Example 2, using NiCr alloy powder as the matrix and Ti3SiC2 powder as the added phase; Figure 3 This is the morphology of the material after sintering in Comparative Example 3, using NiCr alloy powder as the matrix and Ti3SiC2 powder as the added phase; Figure 4 It is a performance comparison of Examples 1 and 2 and Comparative Examples 2 and 3. DETAILED DESCRIPTION

[0021] The specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention. Example 1

[0022] In this embodiment, a high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy is prepared. The alloy comprises, by weight percentage, 93 wt% Ni-20Cr alloy powder, 4 wt% Ti3SiC2 powder, and 3 wt% Si powder. The Ni-20Cr alloy powder has a particle size of 30-50 μm, the Si powder has a particle size of 2 μm, and the Ti3SiC2 powder has a particle size of 3 μm. Specific preparation parameters are as follows: (1) Powder mixing: high-temperature alloy powder, Ti3SiC2 ternary layered carbide ceramic powder, and Si powder were placed in a planetary ball mill according to the ratio and subjected to high-energy ball milling at a speed of 300 rpm for 9 hours to obtain a uniformly mixed composite powder; (2) Pre-pressing: The composite powder obtained in step (1) is placed in a graphite mold and flattened. The composite powder is pre-pressed to 20 MPa at a rate of 10 MPa / min using a cold press, and then unloaded after maintaining for 10 min. (3) Spark plasma sintering: Place the graphite abrasive containing the composite powder into the furnace chamber and sinter it through spark plasma sintering: Vacuum degree is less than 1×10 -2 Pa; sintering temperature is 1100℃; heating rate is 40℃ / min; sintering pressure is 40MPa; holding time is 30 min.

[0023] The density of the sintered alloy is 99.8%; the hardness is 455HV; the yield strength is 1266MPa; the tensile strength is 1545MPa; the elongation is 10.3%; the oxidation weight gain after oxidation at 800℃ for 100 hours is 0.16 mg / cm 2 , the oxidation level is completely antioxidant level. Example 2

[0024] In this embodiment, a high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy is prepared. The alloy is composed of the following components, by weight percentage: 91 wt% Ni-20Cr (wt.%) alloy powder, 6 wt% Ti3SiC2 powder, and 3 wt% Si powder. The Ni-20Cr (wt.%) alloy powder has a particle size of 30-50 μm, the Si powder has a particle size of 2 μm, and the Ti3SiC2 powder has a particle size of 3 μm. The specific preparation parameters are as follows: (1) Powder mixing: Place high-temperature alloy powder, Ti3SiC2 ternary layered carbide ceramic powder, and Si powder in a planetary ball mill according to the ratio and perform high-energy ball milling at a speed of 300 rpm for 9 hours to obtain a uniformly mixed composite powder.

[0025] (2) Pre-pressing: The composite powder obtained in step (1) was placed in a graphite mold and flattened. The composite powder was pre-pressed to 20 MPa at a rate of 10 MPa / min using a cold press, and then unloaded after maintaining for 10 min.

[0026] (3) Spark plasma sintering: Place the graphite abrasive containing the composite powder into the furnace chamber and sinter it through spark plasma sintering: Vacuum degree is less than 1×10 -2 Pa; sintering temperature is 1100℃; heating rate is 40℃ / min; sintering pressure is 40MPa; holding time is 30 min.

[0027] The density of the sintered alloy is 99.8%; the hardness is 435HV; the yield strength is 1542MPa; the tensile strength is 1646MPa; the elongation is 7%; the oxidation weight gain after 100 hours at 800℃ is 0.18 mg / cm 2 , the oxidation level is completely antioxidant level. Example 3

[0028] In this embodiment, a high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy is prepared. The alloy comprises, by weight percentage, 93 wt% Ni-20Cr alloy powder, 4 wt% Ti3AlC2 powder, and 3 wt% Si powder. The Ni-20Cr alloy powder has a particle size of 30-50 μm, the Si powder has a particle size of 2 μm, and the Ti3SiC2 powder has a particle size of 3 μm. The specific preparation parameters are as follows: (1) Powder mixing: Place high-temperature alloy powder, Ti3AlC2 ternary layered carbide ceramic powder, and Si powder in a planetary ball mill according to the ratio and perform high-energy ball milling at a speed of 300 rpm for 9 hours to obtain a uniformly mixed composite powder.

[0029] (2) Pre-pressing: The composite powder obtained in step (1) was placed in a graphite mold and flattened. The composite powder was pre-pressed to 20 MPa at a rate of 10 MPa / min using a cold press, and then unloaded after maintaining for 10 min.

[0030] (3) Spark plasma sintering: Place the graphite abrasive containing the composite powder into the furnace chamber and sinter it through spark plasma sintering: Vacuum degree is less than 1×10 -2Pa; sintering temperature is 1100℃; heating rate is 40℃ / min; sintering pressure is 40MPa; holding time is 30 min.

[0031] The density of the sintered alloy is 99.8%; the hardness is 436HV; the yield strength is 1195MPa; the tensile strength is 1520MPa; the elongation is 10.6%; the oxidation weight gain after oxidizing at 800℃ for 100 hours is 0.17 mg / cm 2 , the oxidation level is completely antioxidant level. Example 4

[0032] In this embodiment, a high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy is prepared. The alloy has a Ni-20Cr-3Al (wt.%) superalloy matrix and is composed of the following components: 93 wt.% Ni-20Cr-3Al (wt.%) alloy powder, 4 wt.% Ti3SiC2 powder, and 3 wt.% Si powder. The Ni-20Cr-3Al (wt.%) alloy powder has a particle size of 50-80 μm, and the Ti3SiC2 powder has a particle size of 3 μm. The specific preparation parameters are as follows: (1) Powder mixing: Place high-temperature alloy powder, Ti3SiC2 ternary layered carbide ceramic powder, and Si powder in a planetary ball mill according to the ratio and perform high-energy ball milling at a speed of 300 rpm for 50 hours to obtain a uniformly mixed composite powder.

[0033] (2) Pre-pressing: The composite powder obtained in step (1) was placed in a graphite mold and flattened. The composite powder was pre-pressed to 20 MPa at a rate of 10 MPa / min using a cold press, and then unloaded after maintaining for 10 min.

[0034] (3) Spark plasma sintering: Place the graphite abrasive containing the composite powder into the furnace chamber and sinter it through spark plasma sintering: Vacuum degree is less than 1×10 -2 Pa; sintering temperature is 1100℃; heating rate is 60℃ / min; sintering pressure is 50MPa; holding time is 10min.

[0035] The density of the sintered alloy is 99.8%; the hardness is 480HV; the yield strength is 1352MPa; the tensile strength is 1621MPa; and the elongation is 9.7%. Example 5

[0036] In this embodiment, a high-strength, high-toughness, and oxidation-resistant plain high-temperature alloy is prepared. The alloy comprises, by weight percentage, 93 wt% Co-20Cr alloy powder, 4 wt% Ti3SiC2 powder, and 3 wt% Si powder. The particle size of the Co-20Cr alloy powder is 30-60 μm, the particle size of the Si powder is 2 μm, and the particle size of the Ti3SiC2 powder is 3 μm. The specific preparation parameters are as follows: (1) Powder mixing: high-temperature alloy powder, Ti3SiC2 ternary layered carbide ceramic powder, and Si powder were placed in a planetary ball mill according to the ratio and subjected to high-energy ball milling at a speed of 300 rpm for 9 hours to obtain a uniformly mixed composite powder; (2) Pre-pressing: The composite powder obtained in step (1) was placed in a graphite mold and flattened. The composite powder was pre-pressed to 20 MPa at a rate of 10 MPa / min using a cold press, and then unloaded after maintaining for 10 min.

[0037] (3) Spark plasma sintering: Place the graphite abrasive containing the composite powder into the furnace chamber and sinter it through spark plasma sintering: Vacuum degree is less than 1×10 -2 Pa; sintering temperature is 1100℃; heating rate is 40℃ / min; sintering pressure is 40MPa; holding time is 30 min.

[0038] The density of the sintered alloy is 99.8%; the hardness is 475HV; the yield strength is 1276MPa; the tensile strength is 1573MPa; and the elongation is 9.1%. Example 6

[0039] In this embodiment, a high-strength, high-toughness, and oxidation-resistant elemental high-temperature alloy is prepared. The alloy comprises a Ni-30Co-20Cr (wt.%) superalloy matrix. The alloy is composed, by weight percentage, of 93 wt.% Ni-30Co-20Cr (wt.%) alloy powder, 4 wt.% Ti3SiC2 powder, and 3 wt.% Si powder. The Ni-30Co-20Cr (wt.%) alloy powder has a particle size of 30-70 μm, the Si powder has a particle size of 2 μm, and the Ti3SiC2 powder has a particle size of 3 μm. Specific preparation parameters are as follows: (1) Powder mixing: high-temperature alloy powder, Ti3SiC2 ternary layered carbide ceramic powder, and Si powder were placed in a planetary ball mill according to the ratio and subjected to high-energy ball milling at a speed of 300 rpm for 9 hours to obtain a uniformly mixed composite powder; (2) Pre-pressing: The composite powder obtained in step (1) was placed in a graphite mold and flattened. The composite powder was pre-pressed to 20 MPa at a rate of 10 MPa / min using a cold press, and then unloaded after maintaining for 10 min.

[0040] (3) Spark plasma sintering: Place the graphite abrasive containing the composite powder into the furnace chamber and sinter it through spark plasma sintering: Vacuum degree is less than 1×10 -2 Pa; sintering temperature is 1100℃; heating rate is 40℃ / min; sintering pressure is 40MPa; holding time is 30 min.

[0041] The density of the sintered alloy is 99.4%; the hardness is 387HV; the yield strength is 1207MPa; the tensile strength is 1452MPa; and the elongation is 14.3%.

[0042] Comparative Example 1 The difference between this comparative example and Example 1 is that the alloy is sintered by ordinary vacuum hot pressing, and the parameters are: vacuum degree: 1×10 -3 atm; sintering temperature: 1100°C; heating rate: 10°C / min, keeping at the final sintering temperature for 15 min and then cooling naturally; sintering pressure: 40 MPa.

[0043] The density of the sintered alloy is 96.5%, which is lower than that of spark plasma sintered materials. The hardness is 325HV; the yield strength is 652MPa; the tensile strength is 946MPa; and the elongation is 9.1%.

[0044] Comparative Example 2 The difference between this comparative example and Example 1 is that the alloy composition ratio is: Ni-20Cr (wt.%) alloy powder 96wt%, Ti3SiC2 powder 4wt%.

[0045] The density of the sintered alloy is 99.4%; the hardness is 355HV; the yield strength is 879MPa; the tensile strength is 1137MPa; and the elongation is 17.8%.

[0046] Comparative Example 3 The difference between this comparative example and Example 1 is that the alloy composition ratio is: Ni-20Cr (wt.%) alloy powder 94wt%, Ti3SiC2 powder 6wt%.

[0047] The density of the sintered alloy is 99.3%, the hardness is 404HV; the yield strength is 1042MPa; the tensile strength is 1125MPa; and the elongation is 9.6%.

[0048] Comparative Example 4 The difference between this comparative example and Example 1 is that the alloy composition ratio is: Ni-20Cr (wt.%) alloy powder 100 wt%.

[0049] The density of the sintered alloy is 99.1%; the hardness is 164HV; the yield strength is 250MPa; the tensile strength is 645MPa; and the elongation is 41.1%.

[0050] Comparative Example 5 The difference between this comparative example and Example 2 is that the alloy composition ratio is: Ni-20Cr (wt.%) alloy powder 94wt%, Ti3SiC2 powder 6wt%.

[0051] The density of the sintered alloy is 99.3%, the hardness is 404HV; the yield strength is 1042MPa; the tensile strength is 1125MPa; and the elongation is 9.6%.

[0052] Comparative Example 6 The difference between this comparative example and Example 2 is that the alloy was ball-milled in a planetary ball mill at a rotation speed of 300 rpm for 18 hours.

[0053] The density of the sintered alloy is 99.9%, the hardness is 475HV; the yield strength is 1584MPa; the tensile strength is 1735MPa; and the elongation is 4.3%.

[0054] Comparative Example 7 The difference between this comparative example and Example 2 is that the spark plasma sintering temperature is 1000°C.

[0055] The density of the sintered alloy is 99.9%, the hardness is 497HV; the yield strength is 1637MPa; the tensile strength is 1793MPa; and the elongation is 5.1%.

[0056] Comparative Example 8 The difference between this comparative example and Example 3 is that the alloy composition ratio is: Ni-20Cr (wt.%) alloy powder 96 wt%, Ti3AlC2 powder 4 wt%.

[0057] The density of the sintered alloy is 99.4%; the hardness is 323HV; the yield strength is 845MPa; the tensile strength is 1084MPa; and the elongation is 16.4%.

[0058] Comparative Example 9 The difference between this comparative example and Example 4 is that the alloy composition ratio is: Ni-20Cr-3Al (wt.%) alloy powder 96 wt%, Ti3SiC2 powder 4 wt%.

[0059] The density of the sintered alloy is 99.4%; the hardness is 389HV; the yield strength is 927MPa; the tensile strength is 1154MPa; and the elongation is 14.7%.

[0060] Comparative Example 10 The difference between this comparative example and Example 4 is that the alloy composition ratio is: Ni-20Cr-3Al (wt.%) alloy powder 94 wt%, Ti3SiC2 powder 6 wt%.

[0061] The density of the sintered alloy is 99.1%, the hardness is 457HV; the yield strength is 1125MPa; the tensile strength is 1179MPa; and the elongation is 8.3%.

[0062] Comparative Example 11 The difference between this comparative example and Example 5 is that the alloy composition ratio is: Co-20Cr (wt.%) alloy powder 96 wt%, Ti3SiC2 powder 4 wt%.

[0063] The density of the sintered alloy is 99.3%, the hardness is 404HV; the yield strength is 912MPa; the tensile strength is 1152MPa; and the elongation is 16.8%.

[0064] The results of the examples and comparative examples show that: like Figure 1 The microstructure of the sintered material from Example 1 is shown, showing the uniform distribution of nanocarbides within the grains. This is due to the introduction of Si particles and the optimization of the ball milling process. The pre-pressing process not only increases the initial density of the powder but also reduces the porosity that may occur during sintering, thereby improving the density of the final material.

[0065] like Figure 2 、 Figure 3 The morphology of the sintered materials without adding Si particles in Comparative Examples 2 and 3 is shown. It can be seen that the carbides are mainly concentrated at the particle boundaries, resulting in a significant decrease in the strength and plasticity of the material. Figure 1 Due to the introduction of Si particles, carbides are evenly distributed within the crystal, significantly improving the material properties.

[0066] At the same time, the performance of the samples sintered by different sintering equipment in Comparative Example 1 was also affected overall.

[0067] Attachment Figure 4 The tensile stress-strain curves of Example 12 and Comparative Example 23 are shown. It can be seen that the yield strength and tensile strength of Example 12 are significantly higher than those of the comparative example, and the elongation is also maintained at a high level, indicating that the material has both high strength and high toughness.

[0068] The core of the design of the present invention is to introduce Si particles to regulate the current size and temperature field distribution in the local area of the alloy during the spark plasma sintering process. During the sintering process, Ti3SiC2 decomposes to form fine nano-TiC clusters, and some nano-TiC can flow into the crystal, thereby avoiding the segregation of carbides at the grain boundaries in traditional powder metallurgy methods. The introduction of Si particles not only regulates the local current and temperature field, but also promotes the uniform distribution of nano-carbides. While improving the strength of the material, it maintains good plasticity, reduces the material's dependence on alloying elements, improves material recovery efficiency and reduces costs, and achieves the purpose of material sintering.

[0069] The above description is merely a preferred embodiment of the present invention. Those skilled in the art will appreciate that the present invention is not limited to the above detailed composition and preparation methods. Any improvements to the present invention, substitutions of raw materials, and additions of auxiliary ingredients are within the scope of protection and disclosure of the present invention.

Claims

1. A high-strength, high-toughness, and oxidation-resistant alloy, characterized in that: The alloy consists of the following components by weight: High temperature alloy matrix powder 90-95%; Ti3SiC2 or Ti3AlC2 ternary layered carbide ceramic powder 3-6%; Si powder 2-5%; The high-temperature alloy matrix is MCr or MCrAl, wherein M is Ni, Co or any combination thereof, the mass percentage of Cr is 15-30%, and the mass percentage of Al is ≤5%.

2. The high-strength, high-toughness, and oxidation-resistant elemental high-temperature alloy according to claim 1, characterized in that: The particle size of the high-temperature alloy powder is 30 to 100 μm, the particle size of the Ti3SiC2 or Ti3AlC2 ternary layered carbide ceramic powder is ≤3 μm, and the particle size of the Si powder is ≤2 μm.

3. The method for preparing a high-strength, high-toughness, and oxidation-resistant elemental high-temperature alloy according to claim 1, characterized in that: The following steps are involved: (1) Powder mixing: Place high-temperature alloy powder, Ti3SiC2 or Ti3AlC2 ternary layered carbide ceramic powder, and Si powder in a planetary ball mill according to the ratio and perform high-energy ball milling. The main disc speed is 300-400 rpm and the ball milling time is 5-50 hours to obtain a uniformly mixed composite powder. (2) Pre-pressing: The composite powder obtained in step (1) is placed into a graphite grinding tool and flattened, and then pre-pressed using a cold press; (3) Spark plasma sintering: The graphite grinding tool loaded with the composite powder in step (2) is placed in the furnace chamber of the spark plasma sintering equipment for sintering. After the sintering is completed, the alloy is obtained by cooling the furnace.

4. The method for preparing the high-strength, high-toughness, and oxidation-resistant elemental high-temperature alloy according to claim 3, characterized in that: The ball mill and the mixed material used in the planetary ball mill in step (1) are both made of cemented carbide, the ball-to-material ratio is 10:1, and argon is introduced as a protective gas.

5. The method for preparing the high-strength, high-toughness, and oxidation-resistant elemental high-temperature alloy according to claim 3, characterized in that: In the step (2), a cold press is used to pre-press the pressure to 20 MPa at a rate of 10 MPa / min, and the pressure is maintained for 10 minutes before unloading.

6. The method for preparing the high-strength, high-toughness, and oxidation-resistant elemental high-temperature alloy according to claim 3, characterized in that: The process parameters of the spark plasma sintering are: vacuum degree is less than 1×10 -2 Pa; sintering temperature is 1100-1200°C; heating rate is 40-60°C / min; sintering pressure is 30-50 MPa; holding time is 10-30 min.

7. The method for preparing the high-strength, high-toughness, and oxidation-resistant elemental high-temperature alloy according to claim 3, characterized in that: The Ti3SiC2 or Ti3AlC2 ternary layered carbide ceramic powder decomposes to generate nano-TiC clusters during the sintering process, and part of the nano-TiC is distributed in the crystal.

8. The high-strength, high-toughness, and oxidation-resistant elemental high-temperature alloy according to claim 1, characterized in that: Its performance indicators are: density ≥99%; hardness ≥400HV; yield strength ≥1100MPa; tensile strength ≥1400MPa; elongation ≥6%; in the temperature range of 200-900℃, the alloy's oxidation resistance level is fully oxidation-resistant.

Images