High-plasticity single-phase FCC high-entropy alloy and preparation method thereof

Abstract

The invention provides a high-plasticity single-phase FCC high-entropy alloy and a preparation method thereof, and relates to the technical field of alloy materials, the general formula of the single-phase FCC high-entropy alloy is (CoaCrbFecNidMoe) 100-fCf, a, b, c, d, e and f are the molar percentages of corresponding elements, and alt is larger than or equal to 45; 45.5, 23 < = blt; 23.5, 13.5 < = clt; 14, 13.5 < = dlt; 14, 5 < = ilt; 0 < = f < = 2, and a + b + c + d + e = 100. Through microalloying of the C element, lattice distortion is generated in an FCC metal matrix, the solid solution strengthening effect is achieved, and after a proper amount of C atoms are added, the grain size of the alloy is reduced, the number of precipitated phases is increased, and the strength of the alloy is remarkably improved; and by adding the C element, the FCC phase structure is stabilized, the stacking fault energy of the alloy is increased, and the strength and plasticity of the alloy are synchronously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and particularly to a single-phase FCC high-entropy alloy with high strength and plasticity and a preparation method thereof. Background Art

[0002] Traditional alloy materials contain only one or two main elements. The common method to improve their properties is usually to add trace amounts of other alloying elements, which leads to an increasingly narrow space for the development of new materials and the improvement of material properties. This situation gradually restricts the development of new alloys and the improvement of the service performance of materials, forcing people to urgently develop new alloys with more outstanding properties. In 2004, Ye Junwei et al. and Cantor et al. successively reported a single-phase solid solution alloy composed of multiple main elements and mixed in an equiatomic ratio. Due to the significant increase in the mixing entropy of the system caused by the increase in the number of main elements, it was named high-entropy alloy. The alloy design concept of multi-main elements in high-entropy alloys breaks away from the constraints of the inherent properties of the main elements, realizes "free" design and combination at the atomic level, and provides a new way to solve the restrictive relationship between the strength and toughness of metal materials.

[0003] Face-centered cubic (FCC) structure high-entropy alloys show great potential in the field of extreme environment structural materials due to their excellent low-temperature toughness, fatigue resistance, and work hardening ability. However, traditional FCC high-entropy alloys generally have the bottleneck problem of low yield strength at room temperature and medium-low temperature conditions, and their strength level is difficult to meet the urgent needs of high-strength materials in high-end fields such as aerospace and deep-sea equipment. Developing an FCC-based high-entropy alloy system with both high strength and high plasticity and its preparation process is of great strategic significance for promoting the industrial application of advanced structural materials. Summary of the Invention

[0004] The purpose of the present invention is to propose a CoCrFeNi-based high-entropy alloy with synergistically improved strength and plasticity and a preparation method thereof for the problem that traditional face-centered cubic high-entropy alloys often exhibit excellent plasticity but low strength due to their numerous slip systems. This alloy consists of a single FCC phase, has a typical dendritic structure, and the addition of a small amount of C element not only enables the matrix alloy to achieve a solid solution strengthening effect, but also changes the alloy deformation mechanism from being dominated by the transformation-induced plasticity (TRIP) effect to being dominated by the twinning-induced plasticity (TWIP) effect, resulting in the simultaneous improvement of the strength and plasticity of the alloy.

[0005] The technical solution adopted by the present invention is as follows: A single-phase FCC high-entropy alloy with high strength and plasticity, wherein: the general formula of the single-phase FCC high-entropy alloy is (Co a Cr b Fe c Ni d Moe ) 100-f C f , where a, b, c, d, e, and f are the molar percentages of the corresponding elements, and 45 ≤ a < 45.5, 23 ≤ b < 23.5, 13.5 ≤ c < 14, 13.5 ≤ d < 14, 5 ≤ e < 5.5, 0 ≤ f ≤ 2, and a + b + c + d + e = 100.

[0006] The present invention also provides a method for preparing a strongly plastic single-phase FCC high-entropy alloy, which includes the following steps: Step S1. Weigh the raw materials of Co, Cr, Fe, Ni, Mo, and FeC. Add Co, Cr, Fe, Ni, Mo, and C to the crucible for mixing according to the molar ratio of CoaCrbFecNidMoe:C of 100 - f:f. Then add a titanium ingot to another crucible. Subsequently, place the crucibles containing the titanium ingot and the raw materials in different charging areas of the melting furnace. Step S2. Pump the melting chamber of the melting furnace to a primary vacuum P1, then pump the melting furnace to a vacuum degree of P2, and then fill it with an inert gas to a vacuum degree of P3, and repeat this step 2 - 3 times. Step S3. Vacuum melt the titanium ingot 1 - 3 times. Step S4. Vacuum melt the raw materials to obtain a as-cast sample. Step S5. Place the as-cast sample obtained in Step S4 on the casting table, repeat Step S2, and then melt the alloy ingot and pour it into a mold to obtain an alloy plate.

[0007] Preferably, in the method for preparing the strongly plastic single-phase FCC high-entropy alloy, in Step S1, the raw materials of Co, Fe, and Ni are placed at the bottom of the crucible, and the raw materials of Cr, Mo, and FeC are placed at the upper part of the crucible.

[0008] Preferably, in the method for preparing the strongly plastic single-phase FCC high-entropy alloy, in Step S2, the primary vacuum P1 is 3 - 6 Pa, P2 ≤ 3×10 -3 Pa, and P3 is -0.04 to -0.06 MPa.

[0009] Preferably, in the method for preparing the strongly plastic single-phase FCC high-entropy alloy, in Step S3, the melting time of the titanium ingot each time is 90 - 120 s.

[0010] Preferably, in the method for preparing the strongly plastic single-phase FCC high-entropy alloy, in Step S4, the vacuum melting is specifically carried out by vacuum melting until all the raw material particles are melted, then starting stirring, subsequently turning over the alloy ingot obtained from the primary melting, and melting again, repeating the melting at least 5 times to obtain an as-cast sample.

[0011] Preferably, in the preparation method of the strong plastic single-phase FCC high-entropy alloy, in step S4, the initial current for vacuum melting is 200-300 A, and the melting current is 600-800 A.

[0012] Preferably, in the preparation method of the strong plastic single-phase FCC high-entropy alloy, the melting furnace is a non-consumable vacuum arc melting furnace, and in step S4, the arc distance during vacuum melting is 20-25 mm.

[0013] Advantages of the present invention: (1) For the strong plastic single-phase FCC high-entropy alloy and its preparation method of the present invention, through the microalloying of C element, lattice distortion is generated inside the FCC metal matrix, achieving a solid solution strengthening effect. After adding an appropriate amount of C atoms, the grain size of the alloy decreases, the number of precipitation phases increases, and the strength of the alloy is significantly improved.

[0014] (2) For the strong plastic single-phase FCC high-entropy alloy and its preparation method of the present invention, the addition of C element, on the one hand, stabilizes the FCC phase structure, and on the other hand, increases the stacking fault energy of the alloy, making the alloy deformation mechanism change from transformation-induced plasticity (TRIP) effect to twinning-induced plasticity (TWIP) effect, and the strength and plasticity of the alloy are improved simultaneously.

[0015] (3) For the strong plastic single-phase FCC high-entropy alloy and its preparation method of the present invention, the preparation method is simple, and high strength and ultra-high plasticity can be exhibited in the as-cast state. Further adding processes such as deformation and heat treatment will obtain more excellent combination of strength and plasticity, showing great potential in industrial applications.

[0016] (4) For the strong plastic single-phase FCC high-entropy alloy and its preparation method of the present invention, the alloy has a single-phase FCC structure and shows a typical dendritic structure; while the strength and plasticity of the single-phase FCC high-entropy alloy are improved in the as-cast state, the yield strength is increased by more than twice, the tensile strength is increased by more than 200 MPa, and at the same time, the plasticity is also significantly improved. Description of the drawings

[0017] Figure 1 XRD diffraction patterns of the strong plastic single-phase FCC high-entropy alloys of Examples 1-3 and the comparative example.

[0018] Figure 2 Comparison diagram of the room-temperature tensile engineering stress-strain curves of the strong plastic single-phase FCC high-entropy alloys of Examples 1-3 and the comparative example in the as-cast state.

[0019] Figure 3 Comparison diagram of the work hardening rate curves of the strong plastic single-phase FCC high-entropy alloys of Examples 1-3 and the comparative example in the as-cast state. Detailed implementation manners

[0020] The present invention will be further described below in conjunction with specific drawings and embodiments.

[0021] Embodiment 1 A strongly plastic single-phase FCC high-entropy alloy, the general formula of the single-phase FCC high-entropy alloy is (Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5) 99.5 C 0.5 .

[0022] The preparation method of the strongly plastic single-phase FCC high-entropy alloy of this embodiment includes the following steps: Step S1. Weigh metal particles of Co, Cr, Fe, Ni, Mo, and FeC with purities of 99.99%, 99.99%, 99.95%, 99.95%, 99.99%, and 99.99% respectively as raw materials. The C element is added in the form of an FeC master alloy (where the C element accounts for 5 wt.%). The total amount of Fe consists of two forms: elemental Fe and FeC. Each element is incorporated in an equimolar number of atoms. The total amount of raw materials is 140 g, and the metal particle size is 3 mm × 3 mm × 3 mm. Add Co, Cr, Fe, Ni, Mo, and C to the crucible for mixing according to the molar ratio of Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5:C of 99.5:0.5. Place the raw materials of Co, Fe, and Ni with relatively low melting points at the bottom of the crucible, and place the raw materials of Cr, Mo, and FeC with relatively high melting points at the upper part of the crucible. At the same time, considering the particle size of the elemental materials, place the elements with smaller particle sizes in the middle and lower parts of the crucible to avoid being blown away by the arc. Then add a titanium ingot to another crucible, and then place the crucibles containing the titanium ingot and the raw materials in different feeding areas of a non-consumable vacuum arc melting furnace. The total amount of raw materials is 140 g; Step S2. Close the furnace door to ensure the airtightness of the furnace body. Start the mechanical pump to pump the melting chamber of the melting furnace to a primary vacuum of 3 Pa. Turn on the molecular pump, and then pump the melting furnace to a vacuum degree of 3 × 10 -3 Pa. Then fill the furnace with high-purity argon gas until the vacuum degree reaches -0.05 MPa. The purity of the high-purity argon gas is ≥99.999%, and repeat this step 3 times to remove the residual air and prevent melting oxidation; Step S3. Vacuum melt the titanium ingot alternately in the positive and negative directions 3 times. The melting time of the titanium ingot each time is 120 s to remove the excess oxygen in the furnace and create a vacuum environment; Step S4. Vacuum melt the raw materials. Specifically, vacuum melt until all the raw material particles are melted, then start stirring. The current of the electromagnetic stirring is increased to 15 A to improve the melting uniformity. During the vacuum melting process, the initial current is 200 A. After forming a skull, gradually increase the melting current to 600 A. The arc distance during vacuum melting is 22 mm to avoid contamination caused by the contact between the electrode and the molten pool. Subsequently, manually turn the initially melted alloy ingot through the handle and melt it again. Repeat the melting 5 times to eliminate composition segregation and obtain as uniform a (Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5) 99.5 C 0.5 as-cast specimen; Step S5. Place the as-cast specimen obtained in Step S4 on the casting table, close the furnace door tightly, repeat Step S2, and then melt the alloy ingot and pour it into the mold to obtain an alloy plate with dimensions of 80 mm×20 mm×8 mm.

[0023] Example 2 A strongly plastic single-phase FCC high-entropy alloy, and the general formula of the single-phase FCC high-entropy alloy is (Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5) 99 C1.

[0024] The preparation method of the strongly plastic single-phase FCC high-entropy alloy in this example includes the following steps: Step S1. Weigh metal particles of Co, Cr, Fe, Ni, Mo, and FeC with purities of 99.99%, 99.99%, 99.95%, 99.95%, 99.99%, and 99.99% respectively as raw materials. The C element is added in the form of FeC (where the C element accounts for 5 wt.%) master alloy. The total amount of Fe consists of two forms: elemental Fe and FeC. Each element is incorporated according to atomic equimolar fractions. The total amount of raw materials is 140 g, and the size of the metal particles is 3 mm×3 mm×3 mm. Arrange Co, Cr, Fe, Ni, Mo, and C in the order of Co 45 Cr 23 Fe 13.5 Ni 13.5Mix the crucible with Mo5 and C in a molar ratio of 99:1. Place the Co, Fe, and Ni raw materials with relatively low melting points at the bottom of the crucible, and place the Cr, Mo, and FeC raw materials with relatively high melting points at the upper part of the crucible. At the same time, considering the particle size of the elemental materials, place the elements with smaller sizes in the middle and lower parts of the crucible to avoid being blown away by the electric arc. Then add a titanium ingot to another crucible, and then place the crucibles containing the titanium ingot and the raw materials in different charging areas of a non-consumable vacuum arc melting furnace. The total amount of raw materials is 140 g; Step S2. Close the furnace door to ensure the tightness of the furnace body. Start the mechanical pump and evacuate the melting chamber of the melting furnace to a primary vacuum of 3 Pa. Then turn on the molecular pump and evacuate the melting furnace to a vacuum degree of 3×10 -3 Pa. Then fill the furnace with high-purity argon gas until the vacuum degree reaches -0.05 MPa. The purity of the high-purity argon gas is ≥99.999%, and repeat this step 3 times to remove the residual air and prevent melting oxidation; Step S3. Vacuum melt the titanium ingot alternately back and forth 3 times. The melting time of the titanium ingot each time is 120 s to remove the excess oxygen in the furnace and create a vacuum environment; Step S4. Vacuum melt the raw materials. Specifically, vacuum melt until all the raw material particles are melted, then turn on the stirring. The current of the electromagnetic stirring is 15 A to improve the melting uniformity. During the vacuum melting process, the initial current is 200 A. After forming a solidified shell, gradually increase the melting current to 600 A. The arc distance during vacuum melting is 22 mm to avoid contamination caused by the contact between the electrode and the molten pool. Then manually turn the alloy ingot obtained from the first melting through the handle and melt it again. Repeat the melting 5 times to eliminate composition segregation and obtain as uniform as possible (Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5) 99.5 C1 as-cast specimen; Step S5. Place the as-cast specimen obtained in Step S4 on the casting table, close the furnace door, and repeat Step S2. Then melt the alloy ingot and pour it into the mold to obtain an alloy plate with dimensions of 80 mm×20 mm×8 mm.

[0025] Example 3 A strongly plastic single-phase FCC high-entropy alloy, and the general formula of this single-phase FCC high-entropy alloy is (Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5) 98 C2.

[0026] The preparation method of the strongly plastic single-phase FCC high-entropy alloy in this example includes the following steps: Step S1. Weigh metal particles of Co, Cr, Fe, Ni, Mo, and FeC with purities of 99.99%, 99.99%, 99.95%, 99.95%, 99.99%, and 99.99% respectively as raw materials. The C element is added in the form of FeC (where the C element accounts for 5 wt.%) master alloy. The total amount of Fe consists of two forms: elemental Fe and FeC. Each element is incorporated according to an equimolar number of atoms. The total amount of raw materials is 140 g, and the size of the metal particles is 3 mm × 3 mm × 3 mm. Add Co, Cr, Fe, Ni, Mo, and C into the crucible for mixing according to the molar ratio of Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5:C of 98:2. Place the raw materials of Co, Fe, and Ni with relatively lower melting points at the bottom of the crucible, and place the raw materials of Cr, Mo, and FeC with relatively higher melting points at the upper part of the crucible. At the same time, considering the particle size of the elemental materials, place the elements with smaller sizes in the middle and lower parts of the crucible to avoid being blown away by the arc. Then add a titanium ingot into another crucible, and then place the crucibles containing the titanium ingot and the raw materials in different charging areas of a non-consumable vacuum arc melting furnace. The total amount of raw materials is 140 g; Step S2. Close the furnace door to ensure the tightness of the furnace body. Start the mechanical pump and evacuate the melting chamber of the melting furnace to a primary vacuum of 3 Pa. Then turn on the molecular pump and evacuate the melting furnace to a vacuum degree of 3×10 -3 Pa. Then fill the furnace with high-purity argon gas until the vacuum degree reaches -0.05 MPa. The purity of the high-purity argon gas is ≥99.999%, and repeat this step 3 times to remove the residual air and prevent oxidation during melting; Step S3. Vacuum melt the titanium ingot alternately back and forth 3 times. The melting time of the titanium ingot each time is 120 s to remove the excess oxygen in the furnace and create a vacuum environment; Step S4. Vacuum melt the raw materials. Specifically, start stirring after the raw material particles are completely melted during vacuum melting. The current of the electromagnetic stirring is 15 A to improve the melting uniformity. During the vacuum melting process, the initial current is 200 A. After a solidified shell is formed, gradually increase the melting current to 600 A. The arc distance during vacuum melting is 22 mm to avoid contamination caused by the contact between the electrode and the molten pool. Then manually turn the alloy ingot obtained from the first melting through the handle and melt it again. Repeat the melting 5 times to eliminate compositional segregation and obtain as uniform as possible a (Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5) 98 C2 as-cast sample; Step S5. Place the as-cast specimen obtained in Step S4 on the casting table, close the furnace door tightly, repeat Step S2, and then melt the alloy ingot and pour it into the mold to obtain an alloy plate with dimensions of 80 mm × 20 mm × 8 mm.

[0027] Comparative example A Co-Cr-Fe-Ni-Mo high-entropy alloy, whose general formula is Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5.

[0028] The preparation method of the Co-Cr-Fe-Ni-Mo high-entropy alloy in this comparative example includes the following steps: Step S1. Weigh metal particles of Co, Cr, Fe, Ni, and Mo with purities of 99.99%, 99.99%, 99.95%, 99.95%, 99.99%, and 99.99% respectively as raw materials. Each element is incorporated in atomic equimolar amounts, and the total amount of raw materials is 140 g. The metal particle size is 3 mm × 3 mm × 3 mm. Add Co, Cr, Fe, Ni, and Mo to the crucible and mix them. Place the raw materials of Co, Fe, and Ni with relatively lower melting points at the bottom of the crucible, and place the raw materials of Cr and Mo with relatively higher melting points at the upper part of the crucible. At the same time, considering the particle size of the elemental materials, place the elements with smaller sizes in the middle and lower parts of the crucible to avoid being blown away by the arc. Then add a titanium ingot to another crucible, and then place the crucibles containing the titanium ingot and the raw materials in different feeding areas of the non-consumable vacuum arc melting furnace. The total amount of raw materials is 140 g; Step S2. Close the furnace door tightly to ensure the airtightness of the furnace body. Start the mechanical pump and pump the melting chamber of the melting furnace to a primary vacuum of 3 Pa. Then turn on the molecular pump and pump the melting furnace to a vacuum degree of 3×10 -3 Pa. Then fill the furnace with high-purity argon gas until the vacuum degree reaches -0.05 MPa. The purity of the high-purity argon gas is ≥99.999%, and repeat this step 3 times to remove the residual air and prevent oxidation during melting; Step S3. Vacuum melt the titanium ingot alternately forward and backward 3 times. The melting time of the titanium ingot each time is 120 s to remove the excess oxygen in the furnace and create a vacuum environment; Step S4. Vacuum melt the raw materials. The vacuum melting is specifically carried out until all the raw material particles are melted, and then start stirring. The current of the electromagnetic stirring is 15 A to improve the melting uniformity. During the vacuum melting process, the initial current is 200 A. After the formation of the ingot shell, gradually increase the melting current to 600 A. The arc distance during vacuum melting is 22 mm to avoid contamination caused by the contact between the electrode and the molten pool. Then manually turn the alloy ingot obtained from the first melting through the handle and melt it again. Repeat the melting 5 times to eliminate compositional segregation and obtain as uniform a Co as possible45 Cr 23 Fe 13.5 Ni 13.5 As-cast sample of Mo5; Step S5. Place the as-cast sample obtained in step S4 on the casting table, close the furnace door tightly, repeat step S2, and then melt the alloy ingot and pour it into the mold to obtain an alloy plate with dimensions of 80 mm × 20 mm × 8 mm.

[0029] Perform XRD diffraction tests and tensile tests on Examples 1 - 3 and the comparative examples. The test results are as Figures 1 - 3 .

[0030] Figure 1 XRD diffraction patterns obtained for Examples 1 - 3 and the comparative examples. It can be seen from Figure 1 that in each of the examples and the comparative examples, the alloy is a single-phase FCC structure. Compared with the comparative examples, in Examples 1 and 2, the (200) diffraction peak gradually shifts to the left, and interstitial C atoms continuously dissolve into the FCC matrix, causing the lattice distortion of the FCC matrix to increase continuously. In Example 3, the (200) diffraction peak significantly shifts to the right, indicating that C atoms have reached the limit of dissolution into the FCC matrix, and a part of the C element forms carbides with metal elements, resulting in a decrease in the lattice distortion of the FCC matrix.

[0031] Figure 2 Engineering stress-strain curves of room-temperature tensile tests obtained for Examples 1 - 3 and the comparative examples. It can be seen from Figure 2 that in Example 1, the yield strength of the (Co 45 Cr 23 Fe 13.5 Ni 13.5 Mo5) 99.5 C 0.5 high-entropy alloy is more than twice that of the comparative example, the tensile strength is also increased by more than 200 MPa, and at the same time, the elongation increases by 6%. It can be seen that the strength and plasticity of the alloy are synergistically improved.

[0032] Figure 3 Curves of work-hardening rate obtained for Examples 1 - 3 and the comparative examples. It can be seen from Figure 3 that in Comparative Example 1 and Examples 1 and 2, the work-hardening rate curves have similar trends of change. They are divided into three regions: I, II, and III. The first stage is the rapid decline region of the work-hardening rate, where the alloy deformation is less than 5%, belonging to the plastic deformation process dominated by dislocation slip. The second stage is the continuously increasing region of the work-hardening rate, where the alloy deformation is between 5% and 20%, belonging to the plastic deformation process dominated by twinning-induced plasticity. The third stage is the decline region of the work-hardening rate, where the alloy deformation is greater than 20%, belonging to the plastic deformation process dominated by dislocation slip.

[0033] Finally, it should be noted that the above specific implementation manners are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A strong and plastic single-phase FCC high-entropy alloy, characterized in that: The general formula of this single-phase FCC high-entropy alloy is (Co a Cr b Fe c Ni d Mo e ), 100-f C f , where a, b, c, d, e, and f are the molar percentages of the corresponding elements, and 45 ≤ a < 45.5, 23 ≤ b < 23.5, 13.5 ≤ c < 14, 13.5 ≤ d < 14, 5 ≤ e < 5.5, 0 ≤ f ≤ 2, and a + b + c + d + e = 100.

2. A method for preparing a strong and ductile single-phase FCC high-entropy alloy according to claim 1, characterized in that: It includes the following steps: Step S1. Weigh the raw materials of Co, Cr, Fe, Ni, Mo, and FeC. Mix Co, Cr, Fe, Ni, Mo, and C in the molar ratio of Co a Cr b Fe c Ni d Mo e :C as 100 - f:f and add them to the crucible. Subsequently, place the titanium ingot in another feeding area of the crucible; Step S2: Pump the melting chamber of the melting furnace to a primary vacuum P1, then pump the melting furnace to a vacuum degree of P2, and then fill it with inert gas to a vacuum degree of P3, and repeat this step 2-3 times; Step S3: Vacuum melt the titanium ingot 1-3 times; Step S4: Vacuum melt the raw materials to obtain a as-cast sample; Step S5: Place the as-cast sample obtained in Step S4 on the casting table, repeat Step S2, and then melt the alloy ingot and pour it into a mold to obtain an alloy plate.

3. The preparation method of the strong plastic single-phase FCC high-entropy alloy according to claim 2, characterized in that: In Step S1, the Co, Fe, and Ni raw materials are placed at the bottom of the crucible, and the Cr, Mo, and FeC raw materials are placed at the upper part of the crucible.

4. The preparation method of the strong plastic single-phase FCC high-entropy alloy according to claim 2, characterized in that: In step S2, the primary vacuum P1 is 3 - 6 Pa, P2 ≤ 3×10 -3 Pa, and P3 is -0.04 to -0.06 MPa.

5. The preparation method of the strongly plastic single-phase FCC high-entropy alloy according to claim 2, characterized in that: In Step S3, the melting time of the titanium ingot each time is 90-120 s.

6. The preparation method of the strong plastic single-phase FCC high-entropy alloy according to claim 2, characterized in that: Specifically, in Step S4, vacuum melting is carried out until all the raw material particles are melted, then stirring is started, and then the alloy ingot obtained from the first melting is turned over and melted again, and the melting is repeated at least 5 times to obtain an as-cast sample.

7. The preparation method of the strong plastic single-phase FCC high-entropy alloy according to claim 2, characterized in that: In Step S4, the initial current for vacuum melting is 200-300 A, and the melting current is 600-800 A.

8. The preparation method of the strong plastic single-phase FCC high-entropy alloy according to claim 2, characterized in that: The melting furnace is a non-consumable vacuum arc melting furnace, and the arc distance during vacuum melting in Step S4 is 20-25 mm.

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