Lightweight high-strength heat-resistant high-entropy alloy and preparation method thereof

Abstract

The invention relates to a light high-strength heat-resistant high-entropy alloy and a preparation method thereof. Specifically, the light high-strength heat-resistant high-entropy alloy comprises the following components in atomic percent: 2 to 10 percent of Cr, 5 to 15 percent of Al, 10 to 20 percent of V, 5 to 20 percent of Nb, 40 to 60 percent of Ti, 2 to 10 percent of Zr and 0.2 to 2.2 percent of Si. The high-entropy alloy has the excellent performance of low density, high strength and high temperature resistance at the same time.

Description

Technical Field

[0001] The present invention relates to the field of high entropy alloys, in particular to a light-weight, high-strength, heat-resistant high entropy alloy, and also to a preparation method of the light-weight, high-strength, heat-resistant high entropy alloy. Background Art

[0002] Lightweight materials can reduce component weight, improve energy efficiency, save resources, and reduce environmental pollution. Therefore, the lightweight design of structural materials has always attracted much attention. However, the development of such lightweight and tough alloys has always been a difficult task in the field of materials research. Usually, the strength and plasticity of metal structural materials are mutually exclusive, and the strength generally decreases as the alloy density decreases.

[0003] At present, traditional lightweight alloy materials with low density and high specific strength mainly include Al alloys, Mg alloys and Ti alloys. These alloys are widely used in the automotive industry, aerospace, electronic components and other fields, making important contributions to energy conservation. However, due to the limitations of traditional alloy design, its composition design and performance improvement space are also limited accordingly, making it difficult to achieve further optimization of material properties.

[0004] The room temperature strength of Al-based and Mg-based alloys usually does not exceed 800 MPa, and they do not have good high temperature resistance and are difficult to work in a temperature environment of 300°C or higher; Ti-based alloys present problems related to strength-plasticity mismatch, and titanium alloys can only have a certain strength at temperatures below 600°C and are difficult to work in a high temperature environment exceeding 600°C. The characteristics of these lightweight alloys limit their further development and application in practical engineering fields.

[0005] Therefore, extreme service environments place more stringent requirements on lightweight structural materials, and it is necessary to develop lightweight, high-strength, and heat-resistant metal structural materials to meet the needs of precision equipment manufacturing and extreme service environments. Summary of the invention

[0006] The purpose of the present disclosure is to provide a lightweight, high-strength, heat-resistant high-entropy alloy and a preparation method thereof, so as to solve the technical problem that it is difficult to simultaneously achieve low density, high strength and high temperature resistance in the prior art alloys.

[0007] In order to achieve the above-mentioned objectives, according to one aspect of the present disclosure, a lightweight, high-strength, heat-resistant, high-entropy alloy is provided. In terms of atomic percentage, the lightweight, high-strength, heat-resistant, high-entropy alloy contains Cr: 2-10%, Al: 5-15%, V: 10-20%, Nb: 5-20%, Ti: 40-60%, Zr: 2-10% and Si: 0.2-2.2%.

[0008] Furthermore, in terms of atomic percentage, the lightweight, high-strength, heat-resistant high-entropy alloy contains Cr: 2-8%, Al: 8-12%, V: 12-20%, Nb: 8-20%, Ti: 40-55%, Zr: 2-8% and Si: 0.2-2.0%.

[0009] Furthermore, in terms of atomic percentage, the lightweight, high-strength, heat-resistant high-entropy alloy contains Cr: 2-8%, Al: 8-12%, V: 12-15%, Nb: 10-18%, Ti: 48-55%, Zr: 2-8% and Si: 0.2-2.0%.

[0010] Furthermore, the lightweight, high-strength, heat-resistant, high-entropy alloy satisfies 5% ≤ (Cr + Zr) ≤ 15% in atomic percentage.

[0011] Furthermore, the purity of the single element raw materials of Cr, Al, V, Nb, Ti, Zr and Si used to form the lightweight, high-strength, heat-resistant and high-entropy alloy exceeds 99.9 wt%.

[0012] According to another aspect of the present disclosure, a method for preparing the lightweight, high-strength, heat-resistant and high-entropy alloy of the present invention is provided, and the method comprises the following steps: step S1, providing raw materials of Cr, Al, V, Nb, Ti, Zr and Si, and removing the surface oxide film by grinding to obtain Cr, Al, V, Nb, Ti, Zr and Si single-substance materials; step S2, placing the Cr, Al, V, Nb, Ti, Zr and Si single-substance materials in a vacuum arc furnace for smelting, obtaining an alloy ingot after cooling, and then smelting the alloy ingot again, wherein the single-substance materials are smelted 5-15 times in the vacuum arc furnace to obtain a molten alloy; and step S3, using a vacuum suction casting device to suction-cast the molten alloy into a copper mold, cooling to room temperature, and obtaining a finished ingot of the lightweight, high-strength, heat-resistant and high-entropy alloy.

[0013] Furthermore, the density of the finished ingot obtained in step S3 is less than 5.5 g / cm 3 .

[0014] Furthermore, the finished ingot obtained in step S3 has a BCC single-phase microstructure.

[0015] Furthermore, the room temperature tensile strength of the finished ingot obtained in step S3 is ≥ 1 GPa, and the elongation is ≥ 10%; the high temperature tensile strength at 600°C is ≥ 800 MPa; and the high temperature tensile strength at 800°C is ≥ 500 MPa.

[0016] As mentioned above, the known prior art alloys have the technical problem of being difficult to achieve low density, high strength and high temperature resistance at the same time. According to the technical solution of the present disclosure, a lightweight, high-strength, heat-resistant high-entropy alloy and a preparation method thereof are provided. By adjusting the appropriate ratio of seven elements, Cr, Al, V, Nb, Ti, Zr and Si, the obtained lightweight, high-strength, heat-resistant high-entropy alloy has a BCC single-phase microstructure, and a Zr-Si strengthening phase is precipitated during the high-temperature smelting process, thereby obtaining a high-entropy alloy with low density (lightweight), high strength and high temperature resistance. The density of the lightweight, high-strength, heat-resistant high-entropy alloy of the present invention is less than 5.5 g / cm 3 , room temperature tensile strength ≥ 1 GPa, elongation ≥ 10%; 600°C high temperature tensile strength ≥ 800 MPa; and 800°C high temperature tensile strength ≥ 500 MPa. Therefore, the lightweight, high-strength, heat-resistant high-entropy alloy of the present invention simultaneously achieves excellent low density (lightweight), high strength and high temperature resistance characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is the XRD spectrum of the ingot according to Example 1 of the present invention.

[0019] Figure 2 is a SEM photograph of the ingot according to Example 1 of the present invention.

[0020] Figure 3 This is a SEM photograph of the ingot according to Example 1 of the present invention after high temperature treatment at 800°C. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present disclosure will be described in detail below in conjunction with the embodiments.

[0022] In response to the deficiencies in the prior art mentioned in the background technology, a specific embodiment of the present disclosure provides a lightweight, high-strength, heat-resistant, high-entropy alloy. In terms of atomic percentage, the lightweight, high-strength, heat-resistant, high-entropy alloy contains Cr: 2-10%, Al: 5-15%, V: 10-20%, Nb: 5-20%, Ti: 40-60%, Zr: 2-10% and Si: 0.2-2.2%.

[0023] It has been found that by adjusting the appropriate ratio of the seven elements of Cr, Al, V, Nb, Ti, Zr, and Si to within the scope of the present invention, a stable BCC (body-centered cubic) single-phase structure can be formed, and the obtained lightweight, high-strength, heat-resistant, high-entropy alloy has a BCC single-phase structure, thereby effectively improving the strength and ductility of the alloy. This is due to the synergistic effect of multiple elements in the alloy and the formation of the BCC single-phase structure, which effectively inhibits the growth of grains and improves the flow strength of the material.

[0024] For example, the lightweight, high-strength, heat-resistant, high-entropy alloy contains 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% Cr by atomic percentage. Preferably, the lightweight, high-strength, heat-resistant, high-entropy alloy contains 2-8% Cr by atomic percentage, more preferably, 5-7% Cr.

[0025] For example, the lightweight, high-strength, heat-resistant, high-entropy alloy comprises 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% Al by atomic percentage. Preferably, the lightweight, high-strength, heat-resistant, high-entropy alloy comprises 8-12% Al by atomic percentage, more preferably, 10-12% Al.

[0026] For example, the lightweight, high-strength, heat-resistant, high-entropy alloy contains 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% V by atomic percentage. Preferably, the lightweight, high-strength, heat-resistant, high-entropy alloy contains 12-15% V by atomic percentage, more preferably, 14-15% V.

[0027] For example, the lightweight, high-strength, heat-resistant, high-entropy alloy comprises 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% Nb by atomic percentage. Preferably, the lightweight, high-strength, heat-resistant, high-entropy alloy comprises 10-18% Nb by atomic percentage, more preferably, 15-18% Nb.

[0028] For example, the lightweight, high-strength, heat-resistant, high-entropy alloy comprises 40%, 42%, 44%, 46%, 48%, 49%, 49.6%, 50%, 51%, 51.8%, 52%, 53%, 54%, 55%, 56%, 58%, 60% Ti. Preferably, the lightweight, high-strength, heat-resistant, high-entropy alloy comprises 48-55% Ti by atomic percentage, more preferably, 49.6-51.8% Ti.

[0029] For example, the lightweight, high-strength, heat-resistant, high-entropy alloy contains 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% Zr. Preferably, the lightweight, high-strength, heat-resistant, high-entropy alloy contains 2-8% Zr by atomic percentage, more preferably, 4-5% Zr.

[0030] For example, the lightweight, high-strength, heat-resistant, high-entropy alloy comprises 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0% Si. Preferably, the lightweight, high-strength, heat-resistant, high-entropy alloy comprises 0.2-2% Si by atomic percentage, more preferably, 0.4-1% Si.

[0031] In some examples, the lightweight, high-strength, heat-resistant high-entropy alloy includes, by atomic percentage, Cr: 2-8%, Al: 8-12%, V: 12-20%, Nb: 8-20%, Ti: 40-55%, Zr: 2-8%, and Si: 0.2-2.0%.

[0032] In some examples, the lightweight, high-strength, heat-resistant high-entropy alloy includes, by atomic percentage, Cr: 2-8%, Al: 8-12%, V: 12-15%, Nb: 10-18%, Ti: 48-55%, Zr: 2-8%, and Si: 0.2-2.0%.

[0033] In addition, through the specific element ratio of the present invention, the high-temperature smelting process of each elemental raw material is conducive to the precipitation of Zr-Si strengthening phase. Under high temperature conditions of 600°C and 800°C, the lightweight, high-strength, heat-resistant, high-entropy alloy of the present invention exhibits tensile strengths of more than 800 MPa and 500 MPa, respectively, and the high-temperature elongation is also maintained at a relatively high level (13% and 61%, respectively). This is due to the Zr-Si strengthening phases formed inside the alloy. These strengthening phases exist stably at high temperatures, effectively improving the high-temperature mechanical properties of the alloy, allowing the material to maintain a stable working state in extreme service environments.

[0034] Due to the specific ratio of Ti, Al and Zr, the obtained lightweight, high-strength, heat-resistant high-entropy alloy has a low density (less than 5.5 g / cm 3 ), compared with conventional Ti alloys, Al alloys and Mg alloys, it can achieve significantly better performance, and is particularly suitable for weight-sensitive applications such as aerospace, high-performance automobiles and precision electronic equipment. Therefore, through a reasonable element ratio, the lightweight, high-strength, heat-resistant high-entropy alloy of the present invention significantly improves the lightweight, high-strength and high-temperature resistance of the material, providing a new metal structural material with excellent performance for the high-end equipment manufacturing industry.

[0035] In some examples, in terms of atomic percentage, the lightweight, high-strength, heat-resistant, high-entropy alloy satisfies 5% ≤ (Cr + Zr) ≤ 15%. When the sum of the atomic percentages of Cr and Zr in the lightweight, high-strength, heat-resistant, high-entropy alloy is within the scope of the present disclosure, the lightweight, high-strength, heat-resistant, high-entropy alloy can better control the microstructure of the alloy during the preparation process, thereby achieving the purpose of optimizing the comprehensive performance of the alloy. When the sum of the atomic percentages of Cr and Zr is within the above range, it can also ensure that during the smelting and post-treatment of the alloy, other elements such as Al, V, Nb, Ti and Si can be more effectively dissolved in the matrix to form a uniform solid solution, thereby obtaining a high-strength and high-temperature resistant lightweight high-entropy alloy material through a complex solid solution and precipitation mechanism.

[0036] In some examples, the purity of the single raw materials of Cr, Al, V, Nb, Ti, Zr, and Si used to form the light-weight, high-strength, heat-resistant, high-entropy alloy exceeds 99.9 wt %. When the purity of the single raw materials used to smelt the light-weight, high-strength, heat-resistant, high-entropy alloy is within the scope of the present disclosure, the introduction of impurities can be reduced, the formation of the second phase during the alloy smelting process can be avoided, unnecessary side reactions during the smelting process can be reduced, and the accuracy and consistency of the alloy composition can be ensured, thereby helping to improve the performance stability of the final product.

[0037] According to another embodiment of the present invention, a method for preparing the lightweight, high-strength, heat-resistant and high-entropy alloy of the present invention is provided, and the method comprises the following steps: step S1, providing raw materials of Cr, Al, V, Nb, Ti, Zr and Si, and removing the surface oxide film by grinding to obtain Cr, Al, V, Nb, Ti, Zr and Si single-substance materials; step S2, placing the Cr, Al, V, Nb, Ti, Zr and Si single-substance materials in a vacuum arc furnace for smelting, obtaining an alloy ingot after cooling, and then smelting the alloy ingot again, wherein the single-substance materials are smelted 5-15 times in the vacuum arc furnace to obtain a molten alloy; and step S3, using a vacuum suction casting equipment to suction-cast the molten alloy into a copper mold, cooling to room temperature, and obtaining a finished ingot of a lightweight, high-strength, heat-resistant and high-entropy alloy.

[0038] The present invention adopts vacuum arc melting and vacuum suction casting process, and by adjusting the specific content ratio of Cr, Al, V, Nb, Ti, Zr, and Si elements, the alloy is lightweight while maintaining high strength and high plasticity. The multi-element synergistic effect makes the tensile strength of the alloy reach more than 1 GPa at room temperature, and the elongation is greater than 10%. At the same time, the tensile strength at high temperatures of 600°C and 800°C reaches more than 800 MPa and 500 MPa, respectively, showing excellent high-temperature strength and plasticity. In addition, the specific content ratio of Cr, Al, V, Nb, Ti, Zr, and Si elements can effectively control the microstructure of the alloy, so that it forms a BCC single-phase structure, which is beneficial to improving the overall performance of the alloy. During the smelting process, the specific content ratio of Zr and Si elements is beneficial to the precipitation of Zr-Si strengthening phase in the alloy. The formation of strengthening phase can improve the strength and heat resistance of the alloy, so that it can still maintain high mechanical properties at high temperatures.

[0039] In some examples, the density of the finished ingot obtained in step S3 is less than 5.5 g / cm 3 For example, the density of the finished ingot is 5.48 g / cm 3 , 5.46 g / cm 3 , 5.44 g / cm 3 , 5.41 g / cm 3 , 5.38 g / cm 3 , 5.35 g / cm 3 , 5.33g / cm 3 , 5.30 g / cm 3 , 5.28 g / cm 3 , 5.26 g / cm 3 , 5.24 g / cm 3 Preferably, the density of the finished ingot is 5.02 g / cm 3 to 5.38 g / cm 3 within the range.

[0040] In some examples, the finished ingot obtained in step S3 has a BCC single-phase microstructure.

[0041] In some examples, the room temperature tensile strength of the finished ingot obtained in step S3 is ≥ 1 GPa, and the elongation is ≥ 10%; the high temperature tensile strength at 600°C is ≥ 800 MPa; and the high temperature tensile strength at 800°C is ≥ 500 MPa. For example, the room temperature tensile strength of the finished ingot is 1056 MPa, 1088 MPa, 1090 MPa, 1100 MPa, etc., and the elongation is 10%, 11%, 12.5%, 15%. For example, the high temperature tensile strength of the finished ingot at 600°C is 825 MPa, 840 MPa, 855 MPa, 886 MPa, etc. For example, the high temperature tensile strength of the finished ingot at 800°C is 590 MPa, 510 MPa, 620 MPa, 697 MPa, etc.

[0042] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0043] Example 1

[0044] The lightweight, high-strength, heat-resistant, high-entropy alloy of Example 1 comprises, in atomic percentage, Cr: 5%, Al: 10%, V: 15%, Nb: 15%, Ti: 49.6%, Zr: 5%, and Si: 0.4%.

[0045] The specific steps of its preparation method are as follows:

[0046] Step S1, providing Cr, Al, V, Nb, Ti, Zr, and Si single-substance raw materials, and performing surface polishing on these single-substance raw materials to remove surface oxide films to obtain Cr, Al, V, Nb, Ti, Zr, and Si single-substance materials.

[0047] Step S2, placing the single-substance materials of Cr, Al, V, Nb, Ti, Zr and Si in a vacuum arc furnace for smelting according to the ratio of the above alloy components, obtaining an alloy ingot after cooling to room temperature, and then smelting the alloy ingot again, repeating the smelting for 5 times to obtain a molten alloy.

[0048] Step S3, using a vacuum suction casting device to suction cast the molten alloy into a copper mold, and rapidly cooling it to room temperature at a rate of about 1500°C / s, thereby obtaining a finished ingot of a high entropy alloy.

[0049] The obtained high entropy alloy finished ingot structure formula is Cr5Al 10 V 15 Nb 15 Ti 49.6 Zr5Si 0.4 The density of the alloy is 5.38 g / cm 3 , and has a BCC single-phase structure (such as Figure 1 As shown), the obtained Cr5Al 10 V 15 Nb 15 Ti 49.6 Zr5Si 0.4 The room temperature tensile strength of the alloy is 1056 MPa, and the elongation is 10%; the high temperature tensile strength at 600°C is 855 MPa, and the elongation is 13%; the high temperature tensile strength at 800°C is 697 MPa, and the elongation is 61% (Table 1).

[0050] Example 2

[0051] The lightweight, high-strength, heat-resistant, high-entropy alloy of Example 2 comprises, in atomic percentage, Cr: 7%, Al: 12%, V: 12%, Nb: 10%, Ti: 55%, Zr: 2%, and Si: 2%.

[0052] The specific steps of its preparation method are as follows:

[0053] Step S1, providing Cr, Al, V, Nb, Ti, Zr, and Si single-substance raw materials, and performing surface polishing on these single-substance raw materials to remove surface oxide films to obtain Cr, Al, V, Nb, Ti, Zr, and Si single-substance materials.

[0054] Step S2, placing the single-substance materials of Cr, Al, V, Nb, Ti, Zr and Si in a vacuum arc furnace for smelting according to the ratio of the above alloy components, obtaining an alloy ingot after cooling to room temperature, and then smelting the alloy ingot again, repeating the smelting for 5 times to obtain a molten alloy.

[0055] Step S3, using a vacuum suction casting device to suction cast the molten alloy into a copper mold, and rapidly cooling it to room temperature at a rate of about 1500°C / s, thereby obtaining a finished ingot of a high entropy alloy.

[0056] The finished high entropy alloy ingot structure is Cr7Al 12 V 12 Nb 10 Ti 55 Zr2Si2, the density of the alloy is 5.02g / cm 3 , and has a BCC single-phase structure (such as Figure 1 As shown), the obtained Cr7Al 12 V 12 Nb 10 Ti 55The room temperature tensile strength of Zr2Si2 alloy is 1100 MPa, and the elongation is 12.5%; the high temperature tensile strength at 600°C is 825 MPa, and the elongation is 16%; the high temperature tensile strength at 800°C is 510 MPa, and the elongation is 22% (Table 1).

[0057] Example 3

[0058] The lightweight, high-strength, heat-resistant, high-entropy alloy of Example 3 comprises, in atomic percentage, Cr: 2%, Al: 12%, V: 15%, Nb: 18%, Ti: 48%, Zr: 4%, and Si: 1%.

[0059] The specific steps of its preparation method are as follows:

[0060] Step S1, providing Cr, Al, V, Nb, Ti, Zr, and Si single-substance raw materials, and performing surface polishing on these single-substance raw materials to remove surface oxide films to obtain Cr, Al, V, Nb, Ti, Zr, and Si single-substance materials.

[0061] Step S2, placing the single-substance materials of Cr, Al, V, Nb, Ti, Zr and Si in a vacuum arc furnace for smelting according to the ratio of the above alloy components, obtaining an alloy ingot after cooling to room temperature, and then smelting the alloy ingot again, repeating the smelting for 15 times to obtain a molten alloy.

[0062] Step S3, using a vacuum suction casting device to suction cast the molten alloy into a copper mold, and rapidly cooling it to room temperature at a rate of about 1500°C / s, thereby obtaining a finished ingot of a high entropy alloy.

[0063] The finished high entropy alloy ingot structure is Cr2Al 12 V 15 Nb 18 Ti 48 Zr4Si, the density of the alloy is 5.37g / cm 3 , and has a BCC single-phase structure (such as Figure 1 As shown), the obtained Cr2Al 12 V 15 Nb 18 Ti 48 The room temperature tensile strength of Zr4Si alloy is 1088 MPa, and the elongation is 11%; the high temperature tensile strength at 600°C is 886 MPa, and the elongation is 23%; the high temperature tensile strength at 800°C is 620 MPa, and the elongation is 30% (Table 1).

[0064] Example 4

[0065] The lightweight, high-strength, heat-resistant, high-entropy alloy of Example 4 comprises, in atomic percentage, Cr: 8%, Al: 8%, V: 14%, Nb: 10%, Ti: 51.8%, Zr: 8%, and Si: 0.2%.

[0066] The specific steps of its preparation method are as follows:

[0067] Step S1, providing Cr, Al, V, Nb, Ti, Zr, and Si single-substance raw materials, and performing surface polishing on these single-substance raw materials to remove surface oxide films to obtain Cr, Al, V, Nb, Ti, Zr, and Si single-substance materials.

[0068] Step S2, placing the single-substance materials of Cr, Al, V, Nb, Ti, Zr and Si in a vacuum arc furnace for smelting according to the ratio of the above alloy components, obtaining an alloy ingot after cooling to room temperature, and then smelting the alloy ingot again, repeating the smelting for 10 times to obtain a molten alloy.

[0069] Step S3, using a vacuum suction casting device to suction cast the molten alloy into a copper mold, and rapidly cooling it to room temperature at a rate of about 1500°C / s, thereby obtaining a finished ingot of a high entropy alloy.

[0070] The finished high entropy alloy ingot structure is Cr8Al8V 14 Nb 10 Ti 51.8 Zr8Si 0.2 The density of the alloy is 5.33 g / cm 3 , and has a BCC single-phase structure (such as Figure 1 As shown), the obtained Cr8Al8V 14 Nb 10 Ti 51.8 Zr8Si 0.2 The room temperature tensile strength of the alloy is 1090 MPa, and the elongation is 15%; the high temperature tensile strength at 600°C is 840 MPa, and the elongation is 45%; the high temperature tensile strength at 800°C is 590 MPa, and the elongation is 30% (Table 1).

[0071] Comparative Example 1

[0072] The high entropy alloy of Comparative Example 1 includes, in atomic percentage, Cr: 1%, Al: 10%, V: 15%, Nb: 15%, Ti: 57.6%, Zr: 1%, and Si: 0.4%.

[0073] The preparation method is the same as that of Example 1, the only difference being the ratio of the alloy components.

[0074] The obtained high entropy alloy finished ingot structure formula is CrAl 10V 15 Nb 15 Ti 57.6 ZrSi 0.4 The density of the alloy is 5.2 g / cm 3 , forming a BCC organizational structure; the room temperature tensile strength is 688 MPa, and the elongation is 21%; the high temperature tensile strength at 600°C is 450 MPa, and the elongation is 13%; the high temperature tensile strength at 800°C is 80 MPa, and the elongation is 15%.

[0075] Comparative Example 2

[0076] The high entropy alloy of Comparative Example 2 includes, in atomic percentage, Cr: 12%, Al: 4%, V: 15%, Nb: 15%, Ti: 48.6%, Zr: 5%, and Si: 0.4%.

[0077] The preparation method is the same as that of Example 1, the only difference being the ratio of the alloy components.

[0078] The obtained high entropy alloy finished ingot structure formula is Cr 12 4V 15 Nb 15 Ti 48.6 Zr5Si 0.4 The density of the alloy is 5.65 g / cm 3 , forming a BCC organizational structure; the room temperature tensile strength is 827 MPa, and the elongation is 7%; the high temperature tensile strength at 600°C is 863 MPa, and the elongation is 17%; the high temperature tensile strength at 800°C is 702 MPa, and the elongation is 62%.

[0079] Comparative Example 3

[0080] The high entropy alloy of Comparative Example 3 includes, in atomic percentage, Cr: 5%, Al: 18%, V: 15%, Nb: 15%, Ti: 34.6%, Zr: 12%, and Si: 0.4%.

[0081] The preparation method is the same as that of Example 1, the only difference being the ratio of the alloy components.

[0082] The obtained high entropy alloy finished ingot structure formula is Cr5Al 18 V 15 Nb 15 Ti 34.6 Zr 12 Si 0.4 The density of the alloy is 5.42 g / cm 3, forming BCC and B2 organizational structures; the room temperature tensile strength is 1121 MPa, and the elongation is 5%; the high temperature tensile strength at 600°C is 505 MPa, and the elongation is 12%; the high temperature tensile properties at 800°C cannot be measured because it cannot withstand the high temperature of 800°C.

[0083] Comparative Example 4

[0084] The high entropy alloy of Comparative Example 4 includes, in atomic percentage, Cr: 5%, Al: 10%, V: 8%, Nb: 3%, Ti: 68.6%, Zr: 5%, and Si: 0.4%.

[0085] The preparation method is the same as that of Example 1, the only difference being the ratio of the alloy components.

[0086] The obtained high entropy alloy finished ingot structure formula is Cr5Al 10 V8Nb3Ti 68.6 Zr5Si 0.4 The density of the alloy is 4.78 g / cm 3 , forming a BCC organizational structure; the room temperature tensile strength is 1002 MPa, and the elongation is 10.5%; the 600°C high temperature tensile strength is 205 MPa, and the elongation is 11%; the 800°C high temperature tensile properties cannot be measured because it cannot withstand 800°C high temperature.

[0087] Comparative Example 5

[0088] The high entropy alloy of Comparative Example 5 includes, in atomic percentage, Cr: 5%, Al: 10%, V: 22%, Nb: 15%, Ti: 42.6%, Zr: 5%, and Si: 0.4%.

[0089] The preparation method is the same as that of Example 1, the only difference being the ratio of the alloy components.

[0090] The obtained high entropy alloy finished ingot structure formula is Cr5Al 10 V 22 Nb 15 Ti 42.6 Zr5Si 0.4 The density of the alloy is 5.49 g / cm 3 , forming a BCC organizational structure; the room temperature tensile strength is 795 MPa, and the elongation is 27%; the 600°C high temperature tensile strength is 425 MPa, and the elongation is 7%; the 800°C high temperature tensile properties cannot be measured because it cannot withstand 800°C high temperature.

[0091] Comparative Example 6

[0092] The high entropy alloy of Comparative Example 6 includes, in atomic percentage, Cr: 5%, Al: 10%, V: 15%, Nb: 22%, Ti: 42.6%, Zr: 5%, and Si: 0.4%.

[0093] The preparation method is the same as that of Example 1, the only difference being the ratio of the alloy components.

[0094] The obtained high entropy alloy finished ingot structure formula is Cr5Al 10 V 15 Nb 22 Ti 42.6 Zr5Si 0.4 The density of the alloy is 5.68 g / cm 3 , forming a BCC organizational structure; the room temperature tensile strength is 927 MPa, and the elongation is 8%; the high temperature tensile strength at 600°C is 790 MPa, and the elongation is 15%; the high temperature tensile strength at 800°C is 610 MPa, and the elongation is 63%.

[0095] Comparative Example 7

[0096] The high entropy alloy of Comparative Example 7 includes, in atomic percentage, Cr: 5%, Al: 10%, V: 15%, Nb: 15%, Ti: 40.5%, Zr: 12%, and Si: 2.5%.

[0097] The preparation method is the same as that of Example 1, the only difference being the ratio of the alloy components.

[0098] The obtained high entropy alloy finished ingot structure formula is Cr5Al 10 V 15 Nb 15 Ti 40.5 Zr 12 Si 2.5 The density of the alloy is 5.50 g / cm 3 , forming BCC and B2 organizational structures; the room temperature tensile strength is 1100 MPa, and the elongation is 7%; the high temperature tensile strength at 600°C is 460 MPa, and the elongation is 15%; the high temperature tensile properties at 800°C cannot be measured because it cannot withstand the high temperature of 800°C.

[0099] Comparative Example 8

[0100] The high entropy alloy of Comparative Example 8 includes, in atomic percentage, Cr: 5%, Al: 10%, V: 15%, Nb: 15%, Ti: 49.9%, Zr: 5%, and Si: 0.1%.

[0101] The preparation method is the same as that of Example 1, the only difference being the ratio of the alloy components.

[0102] The obtained high entropy alloy finished ingot structure formula is Cr5Al 10 V 15 Nb 15 Ti 49.9 Zr5Si 0.1 The density of the alloy is 5.39 g / cm 3 , forming a BCC organizational structure; the room temperature tensile strength is 930 MPa, and the elongation is 11%; the high temperature tensile strength at 600°C is 725 MPa, and the elongation is 35%; the high temperature tensile strength at 800°C is 580 MPa, and the elongation is 22%.

[0103] Table 1 Density, phase structure, tensile strength and elongation of finished ingots of Examples 1-4

[0104]

[0105] Table 2 Density, phase structure, tensile strength and elongation of finished ingots of Comparative Examples 1-8

[0106]

[0107] From the above results, it can be seen that the high entropy alloys of Examples 1-4 having the seven elements in the specific ratio of the present invention have the characteristics of low density, high room temperature tensile strength and excellent high temperature tensile strength. In contrast, the comparative examples without the seven elements in the specific ratio of the present invention have high density, no lightweight characteristics and / or poor tensile strength and elongation at room temperature and high temperature.

[0108] The above embodiments are merely descriptions of the technical solutions of the present disclosure, rather than limiting the scope thereof. Although ordinary technicians in the field can make various modifications with reference to the above examples, they should be within the protection scope of the present disclosure as long as they do not deviate from the design spirit of the present disclosure.

[0109] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0110] The above description only relates to specific embodiments of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A lightweight, high-strength, heat-resistant, high-entropy alloy, characterized in that: In terms of atomic percentage, the lightweight, high-strength, heat-resistant and high-entropy alloy contains Cr: 2-10%, Al: 5-15%, V: 10-20%, Nb: 5-20%, Ti: 40-60%, Zr: 2-10% and Si: 0.2-2.2%.

2. The lightweight, high-strength, heat-resistant, high-entropy alloy according to claim 1, characterized in that: In terms of atomic percentage, the lightweight, high-strength, heat-resistant and high-entropy alloy contains Cr: 2-8%, Al: 8-12%, V: 12-20%, Nb: 8-20%, Ti: 40-55%, Zr: 2-8% and Si: 0.2-2.0%.

3. The lightweight, high-strength, heat-resistant, high-entropy alloy according to claim 1, characterized in that: In terms of atomic percentage, the lightweight, high-strength, heat-resistant and high-entropy alloy contains Cr: 2-8%, Al: 8-12%, V: 12-15%, Nb: 10-18%, Ti: 48-55%, Zr: 2-8% and Si: 0.2-2.0%.

4. The lightweight, high-strength, heat-resistant, high-entropy alloy according to any one of claims 1 to 3, characterized in that: In terms of atomic percentage, the lightweight, high-strength, heat-resistant, high-entropy alloy satisfies 5% ≤ (Cr + Zr) ≤ 15%.

5. The lightweight, high-strength, heat-resistant, high-entropy alloy according to any one of claims 1 to 3, characterized in that: The purity of the single element raw materials of Cr, Al, V, Nb, Ti, Zr and Si used to form the lightweight, high-strength, heat-resistant and high-entropy alloy exceeds 99.9 wt%.

6. A method for preparing a lightweight, high-strength, heat-resistant, high-entropy alloy according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: Step S1, providing raw materials of Cr, Al, V, Nb, Ti, Zr, and Si, and removing the surface oxide film by grinding to obtain Cr, Al, V, Nb, Ti, Zr, and Si single-substance materials; Step S2, placing the single-substance materials of Cr, Al, V, Nb, Ti, Zr, and Si in a vacuum arc furnace for smelting, obtaining an alloy ingot after cooling, and then smelting the alloy ingot again, wherein the single-substance materials are smelted 5-15 times in the vacuum arc furnace to obtain a molten alloy; and Step S3, using vacuum suction casting equipment to suction cast the molten alloy into a copper mold, cooling it to room temperature, and obtaining a finished ingot of the lightweight, high-strength, heat-resistant, high-entropy alloy.

7. The method according to claim 6, characterized in that The density of the finished ingot obtained in step S3 is less than 5.5 g / cm 3 .

8. The method according to claim 6 or 7, characterized in that: The finished ingot obtained in step S3 has a BCC single-phase microstructure.

9. The method according to claim 6 or 7, characterized in that: The finished ingot obtained in step S3 has a room temperature tensile strength of ≥ 1 GPa, an elongation of ≥ 10%; a high temperature tensile strength of 600°C of ≥ 800 MPa; and a high temperature tensile strength of 800°C of ≥ 500 MPa.

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