Ultrahigh-toughness multi-principal-element alloy and preparation method thereof

Abstract

The invention discloses an ultrahigh-toughness multi-principal-element alloy and a preparation method thereof, and relates to a high-entropy alloy and a preparation method thereof. In order to solve the problem that the engineering application prospect of an existing high-entropy alloy AlCoCrFeNi is restricted due to the fact that strength and plasticity are difficult to consider due to confusion of a solidification structure and remarkable composition segregation, the chemical formula of the alloy is as follows: 17.0% of Al, 13.9% of Cr, 13.9% of Fe, 13.9% of Co, 38.4% of Ni and 2.9% of Mo. According to the method, firstly, an alloy ingot is prepared through a directional solidification technology, then the precipitation behaviors, including the type, size, distribution and volume fraction, of a second phase in the alloy are regulated and controlled through a specific heat treatment system, and the synergistic effect of precipitation strengthening and microstructure optimization is achieved. The alloy prepared through the method has ultrahigh strength and toughness, the tensile strength of the alloy is not lower than 1.3 GPa, the percentage elongation after fracture is not lower than 17%, and the method is applied to the technical field of high-performance metal material preparation.

Description

Technical Field

[0001] This invention relates to an ultra-high strength and toughness multi-principal element alloy and its preparation method. Background Technology

[0002] Currently, multi-principal alloys (also known as high-entropy alloys) have become a research hotspot in high-performance metallic materials due to their unique design concepts and performance potential. However, multi-principal alloys prepared by traditional casting, especially the AlCoCrFeNi system, often suffer from disordered solidification structure and significant compositional segregation, making it difficult to balance strength and plasticity, which restricts their engineering application prospects.

[0003] To further optimize strength and toughness, researchers have begun to focus on constructing FCC / BCC dual-phase alloy systems and introducing large atomic radius Mo elements to enhance overall performance through solid solution strengthening and second-phase modulation. However, relying solely on as-cast phase structure design is still insufficient to achieve ideal microstructure control and performance matching.

[0004] Directional solidification technology, by establishing unidirectional heat flow conditions, can effectively suppress the formation of equiaxed crystals and promote the directional growth of columnar crystals, thereby significantly improving the mechanical properties of alloys along the orientation direction. Although directional solidification has advantages in controlling solidification microstructure, in Al-Cr-Fe-Co-Ni-Mo multi-principal element alloys, how to achieve precise control over the precipitation ratio and distribution of the L12 phase through the synergistic process of directional solidification and subsequent heat treatment, and thus obtain materials with a perfect balance of strength and toughness, remains a key problem that has not yet been systematically solved in existing technologies. Summary of the Invention

[0005] This invention aims to address the problem that existing high-entropy alloys AlCoCrFeNi often suffer from disordered solidification structure and significant compositional segregation, which makes it difficult to balance strength and plasticity, thus limiting their engineering application prospects. The invention provides an ultra-high strength and toughness multi-principal element alloy and its preparation method.

[0006] This invention discloses an ultra-high strength and toughness multi-principal element alloy composed of 17.0% Al, 13.9% Cr, 13.9% Fe, 13.9% Co, 38.4% Ni, and 2.9% Mo by atomic percentage, with the chemical formula Al. 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 .

[0007] The present invention discloses a method for preparing an ultra-high strength and toughness multi-principal element alloy as follows:

[0008] 1. Weigh the raw materials according to the atomic percentages of 17.0% Al, 13.9% Cr, 13.9% Fe, 13.9% Co, 38.4% Ni and 2.9% Mo;

[0009] 2. Place the raw materials into the crucible of the non-consumable vacuum melting furnace from top to bottom in order of melting point. After evacuation, fill the furnace with high-purity argon gas for melting. After solidification, repeatedly melt the raw materials to obtain an ingot.

[0010] 3. Cut the ingot into metal rods, then clean them to obtain cleaned metal rods;

[0011] 4. Place the metal rod in a ceramic crucible, and then place it together in a vacuum directional solidification furnace. After evacuating the furnace, argon gas is introduced, and then the furnace is heated and kept warm. When the metal rod melts, it is pulled into the Ga-In liquid at a speed of 150 μm / s. After cooling, the directional solidified alloy rod is obtained.

[0012] 5. Place the directionally solidified alloy bar in a muffle furnace, heat it to 600~800℃ and hold it for 1~24 hours, then take it out and quench it to obtain an ultra-high strength and toughness multi-principal element alloy, thus completing the process.

[0013] This invention combines directional solidification technology with optimized heat treatment processes to achieve precise control over the microstructure of alloys. Specifically, based on the existing solid solution strengthening and second-phase strengthening effects in the alloy, directional solidification is used to eliminate transverse grain boundaries and form a directional columnar crystal structure. Then, heat treatment promotes the precipitation of the L12 ordered phase, ultimately achieving a synergistic improvement in strength and toughness along the alloy growth direction.

[0014] Beneficial effects of this invention:

[0015] I. The Al-Cr-Fe-Co-Ni-Mo multi-component system determined in this invention can stably form a dual-phase microstructure in which FCC and BCC phases coexist. The two phases are complementary in mechanical behavior, with the FCC phase providing good plasticity and the BCC phase contributing high strength, thus achieving a good match between strength and toughness.

[0016] Second, by employing directional solidification technology, the alloy develops a columnar crystal structure that preferentially grows along the heat flow direction, significantly reducing the number of transverse grain boundaries. This structure effectively inhibits the initiation and propagation of cracks along transverse grain boundaries during tensile testing, thereby improving the alloy's strength and damage tolerance.

[0017] Third, the high cooling rate during directional solidification inhibits grain growth and promotes significant microstructure refinement. Grain refinement not only increases the total grain boundary area and enhances grain boundary strengthening, but also helps to improve the material's uniform plastic deformation capacity.

[0018] Fourth, a specially designed heat treatment process promotes the uniform dispersion and precipitation of the strong and tough L12 nanophase in the matrix, while simultaneously spheroidizing the hard and brittle BCC phase. This regulation introduces significant second-phase strengthening while alleviating stress concentration, thereby effectively improving the alloy's plasticity while increasing strength.

[0019] V. This invention organically combines directional solidification technology with heat treatment processes to successfully prepare a multi-principal element alloy with ultra-high strength and toughness, exhibiting a room temperature tensile strength exceeding 1.3 GPa and an elongation after fracture exceeding 17%. The preparation process has a clear route, controllable parameters, and good repeatability, possessing the potential for large-scale production. Attached Figure Description

[0020] Figure 1 Al alloy ingots obtained by smelting 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 Differential scanning calorimetry (DSC) curves;

[0021] Figure 2 The directional solidification of Al during heat treatment at 700℃ / 10h in Example 1 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 Microstructure diagram of a multi-principal element alloy;

[0022] Figure 3 The directional solidification of Al during heat treatment at 600℃ / 24h in Example 2 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 Microstructure diagram of a multi-principal element alloy;

[0023] Figure 4 For the electric arc melting of Al in Comparative Example 1 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 Microstructure diagram of a multi-principal element alloy;

[0024] Figure 5 The directional solidification of Al during heat treatment at 700℃ / 10h in Example 1 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni38.4 Mo 2.9 Electron backscatter diffraction (EBSD) inverse pole figure (IPF) of multi-principal element alloys;

[0025] Figure 6 The directional solidification of Al during heat treatment at 700℃ / 10h in Example 1 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 Scanning transmission electron microscopy (STEM) images of multi-principal element alloys;

[0026] Figure 7 For the vacuum electric arc furnace melting of Al in Comparative Example 1 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 Scanning transmission electron microscopy (STEM) images of multi-principal element alloys;

[0027] Figure 8 The table shows the room temperature stress-strain curves for Examples 1, 2, and 1 (Comparative Example 1). Detailed Implementation

[0028] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0029] Specific Implementation Method 1: This implementation method describes an ultra-high strength and toughness multi-principal element alloy composed of 17.0% Al, 13.9% Cr, 13.9% Fe, 13.9% Co, 38.4% Ni, and 2.9% Mo by atomic percentage, with the chemical formula Al. 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 .

[0030] Specific Implementation Method Two: The preparation method of an ultra-high strength and toughness multi-principal element alloy in this implementation method is as follows:

[0031] 1. Weigh the raw materials according to the atomic percentages of 17.0% Al, 13.9% Cr, 13.9% Fe, 13.9% Co, 38.4% Ni and 2.9% Mo;

[0032] 2. Place the raw materials into the crucible of the non-consumable vacuum melting furnace from top to bottom in order of melting point. After evacuation, fill the furnace with high-purity argon gas for melting. After solidification, repeatedly melt the raw materials to obtain an ingot.

[0033] 3. Cut the ingot into metal rods, then clean them to obtain cleaned metal rods;

[0034] 4. Place the metal rod in a ceramic crucible, and then place it together in a vacuum directional solidification furnace. After evacuating the furnace, argon gas is introduced, and then the furnace is heated and kept warm. When the metal rod melts, it is pulled into the Ga-In liquid at a speed of 150 μm / s. After cooling, the directional solidified alloy rod is obtained.

[0035] 5. Place the directionally solidified alloy bar in a muffle furnace, heat it to 600~800℃ and hold it for 1~24 hours, then take it out and quench it to obtain an ultra-high strength and toughness multi-principal element alloy, thus completing the process.

[0036] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method Two in that: Step Two involves evacuating the vacuum to 3×10⁻⁶. -3 Pa. Everything else is the same as in Specific Implementation Method Two.

[0037] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Two or Three in that: in step two, high-purity argon gas is introduced to a pressure of 50 kPa. Everything else is the same as in Specific Implementation Method Two or Three.

[0038] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods Two to Four in that: after solidification in step two, remelting is repeated 5-7 times, and the ingot is flipped before each remelting to obtain an alloy ingot with uniform composition. Everything else is the same as in Specific Implementation Methods Two to Four.

[0039] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods Two to Five in that the cleaning method for the metal rod in step three is as follows: the surface of the rod is polished step by step with sandpaper to remove cutting marks and oxide layers, and ultrasonic cleaning is performed using anhydrous ethanol. Everything else is the same as in Specific Implementation Methods Two to Five.

[0040] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods Two to Six in that: Step Four involves evacuating the vacuum to 1×10⁻⁶. -3 Pa. The rest is the same as in any of the specific embodiments two to six.

[0041] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods Two to Seven in that: after evacuation in step four, 50 kPa argon gas is introduced. Everything else is the same as in Specific Implementation Methods Two to Seven.

[0042] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Two to Eight in that: in step four, the heating is carried out at a rate of 20-30℃ / min to 1600℃, and the holding time is ≥1h. Everything else is the same as in Specific Implementation Methods Two to Eight.

[0043] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Two to Nine in that the heating rate in step five is 8-12℃ / min. Everything else is the same as in Specific Implementation Methods Two to Nine.

[0044] In this embodiment, the heating rate is controlled at 8-12℃ / min to avoid abnormal grain growth or uncontrolled precipitate formation due to overheating or overheating.

[0045] The beneficial effects of the present invention are verified using the following embodiments:

[0046] Example 1: An Al based on directional solidification and heat treatment 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 A method for strengthening and toughening multi-principal element alloys. The specific steps are as follows:

[0047] (1) Based on the chemical formula Al 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 After converting the values ​​to mass percentages, the corresponding metal raw materials were weighed. To compensate for element loss during the smelting process, each raw material was weighed at 102% of its nominal stoichiometric mass. All metal raw materials had a purity of not less than 99.5 wt.%, and were ultrasonically cleaned with anhydrous ethanol before use to remove surface contaminants. The cleaned metal raw materials were placed in the water-cooled copper crucible of the non-consumable arc furnace in order of increasing melting point from bottom to top. After the furnace was closed, a vacuum of 3 × 10⁻⁶ was applied. -3 The pressure was then increased to 50 kPa by introducing high-purity argon gas with a purity ≥99.999%. To reduce the residual oxygen content in the furnace, approximately 110 grams of titanium ingots with a purity of not less than 99.4% were first melted for oxygen absorption treatment. The alloy raw material was then repeatedly melted under an argon atmosphere, a total of 6 times. Before each remelting, the solidified ingot was turned over to ensure uniform composition. The final product was a button-shaped alloy ingot with a diameter of approximately 5 cm and a thickness of approximately 1 cm.

[0048] (2) A cylindrical rod with a diameter of 7 mm is obtained by cutting along a specified direction from the button ingot. The surface of the rod is then polished step by step with sandpaper to remove cutting marks and oxide layer, and ultrasonically cleaned with anhydrous ethanol. After drying, it is ready for use.

[0049] (3) Place the alloy rod into a ceramic crucible with an inner diameter of 7 mm, and then place it onto the pulling device of the vacuum directional solidification furnace. Evacuate to 10 mm. -3After passing through a pressure of 50 kPa argon gas, heating and holding were initiated. The heating rate was 25 °C / min, reaching 1600 °C, and the holding time was 1 hour. When the alloy was completely melted, it was pulled into the Ga-In liquid at a speed of 150 μm / s to achieve directional growth of the alloy microstructure, ultimately obtaining a directionally solidified alloy rod.

[0050] (4) The alloy rods after directional solidification are heat-treated by heating to 700°C at a heating rate of 10°C / min and holding for 10 hours. Then, they are taken out and water-cooled for quenching to finally obtain the ultra-high strength and toughness multi-principal element alloy.

[0051] The differential scanning calorimetry (DSC) curve of the alloy ingot obtained from smelting is shown in the figure. Figure 1 As shown in the figure. Test results indicate that the alloy has a melting point of approximately 1345℃, and a distinct endothermic peak exists at approximately 817℃, corresponding to the dissolution temperature of the L12 ordered phase. According to the precipitation kinetics principle, to promote the complete precipitation of the L12 strengthening phase from the supersaturated solid solution, the heat treatment temperature should be set below the phase transformation temperature. Therefore, this invention determines the heat treatment temperature range to be 500-800℃. This temperature range is both lower than the dissolution temperature of the L12 phase (817℃), providing a thermodynamic driving force for phase precipitation, and ensures sufficient atomic diffusion capacity, thereby achieving high-density, uniform precipitation of the L12 phase and achieving a significant precipitation strengthening effect.

[0052] This embodiment describes the preparation of Al through directional solidification and subsequent heat treatment. 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 Multi-principal element alloys exhibit excellent microstructure and mechanical properties, such as Figure 2 As shown, the alloy microstructure exhibits a typical columnar crystal morphology along the heat flow direction, with fine and uniform grain size, and spheroidized hard and brittle BCC phase. Electron backscatter diffraction (EBSD) inverse pole figure (IPF) analysis results ( Figure 5 This further demonstrates that the alloy retains its strong properties even after heat treatment. <001> The texture indicates that the oriented structure formed by directional solidification did not degrade during heat treatment. (Scanning transmission electron microscopy (STEM) image) Figure 6 The results show that the alloy matrix contains high-density, uniformly dispersed nanoscale precipitates with a size of 20-50 nm. Room temperature tensile properties were tested. Figure 8 The results show that the alloy has a tensile strength of 1430.03 MPa and an elongation after fracture of 17.87%, exhibiting an excellent balance of strength and toughness.

[0053] Example 2

[0054] An Al based on directional solidification and heat treatment 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 A method for strengthening and toughening multi-principal element alloys, with the chemical formula Al. 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 The specific steps are as follows:

[0055] (1) Based on the chemical formula Al 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 After converting the values ​​to mass percentages, the corresponding metal raw materials were weighed. To compensate for element loss during the smelting process, each raw material was weighed at 102% of its nominal stoichiometric mass. All metal raw materials had a purity of not less than 99.5 wt.%, and were ultrasonically cleaned with anhydrous ethanol before use to remove surface contaminants. The cleaned metal raw materials were placed in the water-cooled copper crucible of the non-consumable arc furnace in order of increasing melting point from bottom to top. After the furnace was closed, a vacuum of 3 × 10⁻⁶ was applied. -3 The pressure was then increased to 50 kPa by introducing high-purity argon gas with a purity ≥99.999%. To reduce the residual oxygen content in the furnace, approximately 110 grams of titanium ingots with a purity of not less than 99.4% were first melted for oxygen absorption treatment. The alloy raw material was then repeatedly melted under an argon atmosphere, a total of 6 times. Before each remelting, the solidified ingot was turned over to ensure uniform composition. The final product was a button-shaped alloy ingot with a diameter of approximately 5 cm and a thickness of approximately 1 cm.

[0056] (2) A cylindrical rod with a diameter of 7 mm is obtained by cutting along a specified direction from the button ingot. The surface of the rod is then polished step by step with sandpaper to remove cutting marks and oxide layer, and ultrasonically cleaned with anhydrous ethanol. After drying, it is ready for use.

[0057] (3) Place the alloy rod into a ceramic crucible with an inner diameter of 7 mm, and then place it onto the pulling device of the vacuum directional solidification furnace. Evacuate to 10 mm. -3 After passing through a pressure of 50 kPa argon gas, heating and holding were initiated. The heating rate was 25 °C / min, reaching 1600 °C, and the holding time was 1 hour. When the alloy was completely melted, it was pulled into the Ga-In liquid at a speed of 150 μm / s to achieve directional growth of the alloy microstructure, ultimately obtaining a directionally solidified alloy rod.

[0058] (4) The alloy rods after directional solidification are heat-treated by heating to 600°C at a heating rate of 10°C / min and holding for 24 hours. Then, they are taken out and water-cooled for quenching to finally obtain the ultra-high strength and toughness multi-principal element alloy.

[0059] In Example 2, Al was prepared by directional solidification and subsequent heat treatment. 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 Multi-principal element alloys exhibit excellent microstructure and mechanical properties. For example... Figure 3 As shown, the alloy microstructure exhibits a typical columnar crystal morphology along the heat flow direction, with fine and uniform grain size. Room temperature tensile property test results ( Figure 8 The results show that the alloy has a tensile strength of 1339.01 MPa and an elongation after fracture of 20.86%, exhibiting an excellent balance of strength and toughness.

[0060] Comparative Example 1

[0061] According to the chemical formula Al 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 After converting the values ​​to mass percentages, the corresponding metal raw materials were weighed. To compensate for element loss during the smelting process, each raw material was weighed at 102% of its nominal stoichiometric mass. All metal raw materials had a purity of not less than 99.5 wt.%, and were ultrasonically cleaned with anhydrous ethanol before use to remove surface contaminants. The cleaned metal raw materials were placed in the water-cooled copper crucible of the non-consumable arc furnace in order of increasing melting point from bottom to top. After the furnace was closed, a vacuum of 3 × 10⁻⁶ was applied. -3 The pressure was then increased to 50 kPa by introducing high-purity argon gas with a purity ≥99.999%. To reduce the residual oxygen content in the furnace, approximately 110 grams of titanium ingots with a purity of not less than 99.4% were first melted for oxygen absorption treatment. The alloy raw materials were then repeatedly melted under an argon atmosphere for a total of 6 times. Before each remelting, the solidified ingot was turned over to ensure uniform composition. The final result was a button-shaped alloy ingot with a diameter of approximately 5 cm and a thickness of approximately 1 cm, which is the alloy of Comparative Example 1.

[0062] In Comparative Example 1, Al was prepared by conventional electric arc melting. 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 The microstructure of the multi-principal element alloy contrasts sharply with that of Examples 1 and 2. For example... Figure 4As shown, the alloy exhibits a typical cast equiaxed crystal structure with disordered grain orientation and no obvious preferred growth direction. Further observation of the distribution of nano-precipitates ( Figure 7 As can be seen, the precipitated phase is sparse in quantity, unevenly distributed, and relatively large in size (approximately 70-100 nm). For example... Figure 8 The tensile test results show that the tensile strength of the alloy is 1068.17 MPa and the elongation after fracture is 11.98%. Its strength and toughness are significantly lower than those of the alloys of Example 1 and Example 2, which were optimized by directional solidification and heat treatment. This fully demonstrates the significant advantages of the process of the present invention in controlling the microstructure and improving the mechanical properties.

[0063] In summary, the "directional solidification + heat treatment" synergistic process provided by this invention overcomes the bottleneck of traditional as-cast multi-principal element alloys where strength and plasticity are difficult to balance. The alloy prepared by this process exhibits a significantly directional microstructure and optimized precipitates, ultimately achieving an ultra-high strength-toughness balance with tensile strength exceeding 1.3 GPa and elongation exceeding 17%, far surpassing the performance of comparative alloys prepared by arc melting.

Claims

1. An ultra-high strength and toughness multi-principal element alloy, characterized in that, This multi-principal element alloy is composed of 17.0% Al, 13.9% Cr, 13.9% Fe, 13.9% Co, 38.4% Ni, and 2.9% Mo by atomic percentage, and has the chemical formula Al. 17.0 Cr 13.9 Fe 13.9 Co 13.9 Ni 38.4 Mo 2.9 .

2. The method for preparing an ultra-high strength and toughness multi-principal element alloy as described in claim 1, characterized in that, The preparation method is as follows:

1. Weigh the raw materials according to the atomic percentages of 17.0% Al, 13.9% Cr, 13.9% Fe, 13.9% Co, 38.4% Ni and 2.9% Mo; 2. Place the raw materials into the crucible of the non-consumable vacuum melting furnace from top to bottom in order of melting point. After evacuation, fill the furnace with high-purity argon gas for melting. After solidification, repeatedly melt the raw materials to obtain an ingot.

3. Cut the ingot into metal rods, then clean them to obtain cleaned metal rods; 4. Place the metal rod in a ceramic crucible, and then place it together in a vacuum directional solidification furnace. After evacuating the furnace, argon gas is introduced, and then the furnace is heated and kept warm. When the metal rod melts, it is pulled into the Ga-In liquid at a speed of 150 μm / s. After cooling, the directional solidified alloy rod is obtained.

5. Place the directionally solidified alloy bar in a muffle furnace, heat it to 600~800℃ and hold it for 1~24 hours, then take it out and quench it to obtain an ultra-high strength and toughness multi-principal element alloy, thus completing the process.

3. The method for preparing an ultra-high strength and toughness multi-principal element alloy according to claim 2, characterized in that, Step 2: Evacuate to 3×10 -3 Pa.

4. The method for preparing an ultra-high strength and toughness multi-principal element alloy according to claim 2, characterized in that, Step 2: Fill with high-purity argon gas to 50 kPa.

5. The method for preparing an ultra-high strength and toughness multi-principal element alloy according to claim 2, characterized in that, After solidification in step two, the ingot is remelted 5-7 times, and the ingot is flipped before each remelting to obtain an alloy ingot with uniform composition.

6. The method for preparing an ultra-high strength and toughness multi-principal element alloy according to claim 2, characterized in that, The cleaning method for the metal rod in step three is as follows: use sandpaper to polish the surface of the rod step by step to remove cutting marks and oxide layer, and use anhydrous ethanol for ultrasonic cleaning.

7. The method for preparing an ultra-high strength and toughness multi-principal element alloy according to claim 2, characterized in that, Step 4: Evacuate to 1×10 -3 Pa.

8. The method for preparing an ultra-high strength and toughness multi-principal element alloy according to claim 2, characterized in that, Step four involves evacuating the vacuum and then filling it with 50 kPa argon gas.

9. The method for preparing an ultra-high strength and toughness multi-principal element alloy according to claim 2, characterized in that, Step four involves heating to 1600℃ at a rate of 20-30℃ / min and holding at that temperature for ≥1 hour.

10. The method for preparing an ultra-high strength and toughness multi-principal element alloy according to claim 2, characterized in that, The heating rate in step five is 8-12℃ / min.

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