High-toughness multi-component alloy and preparation method thereof
By introducing uneven grain size, gradient σ phase and heterogeneous L12 nanometer precipitation phase into the multicomponent alloy, combined with vacuum arc smelting and cold rolling annealing technology, the problem of the multicomponent alloy decreasing ductility when improving the yield strength is solved, and the synergistic effect of high strength and good ductility is achieved.
Patent Information
- Application Number
- CN202510295759.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-13
- Publication Date
- 2025-06-13
AI Technical Summary
While increasing yield strength, existing multicomponent alloys usually sacrifice ductility, making it difficult to achieve strength-plastic synergies.
By preparing a high-strength multicomponent alloy with uneven grain size, gradient σ phase and heterogeneous L12 nanometer precipitation phase, the structural structure of the alloy is optimized by combining vacuum arc smelting and cold rolling annealing processes.
It has achieved a significant improvement in alloy strength while retaining the plasticity of the alloy, significantly improving the strength-plastic synergy effect, and significantly improving the yield strength and ultimate tensile strength.
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Figure CN120138466A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of metal material preparation, and particularly relates to a high-strength and tough multi-component alloy and a preparation method thereof. Background Art
[0002] Multi-component alloys include high-entropy alloys and medium-entropy alloys. Different from traditional low-entropy alloys with a single main element, due to their unique high-entropy effect, lattice distortion effect, sluggish diffusion effect and "cocktail" effect, their microstructure, structure and properties are unique. Therefore, multi-component alloys have many excellent and unique properties, such as good wear resistance, excellent corrosion resistance, high ductility, high strength, excellent oxidation resistance, and have very broad application potential under extreme conditions. However, due to the inherent characteristics of the face-centered cubic (FCC) structure, the tensile yield strength of single-phase FCC multi-component alloys cannot provide the desired strength for engineering applications. Although many mechanisms have been applied to strengthen single-phase FCC multi-component alloys, they usually inevitably sacrifice the alloy plasticity.
[0003] At present, alloys with high strength and sufficient ductility are highly needed in modern engineering applications. Compared with traditional alloys, the unique design concept of multi-component alloys makes them exhibit excellent properties. Among them, the CoCrNi multi-component alloy with a single-phase face-centered cubic structure exhibits excellent elongation at break at room temperature. Although showing excellent room-temperature ductility, the yield strength of as-cast CoCrNi multi-component alloys is still lower than 400 MPa, which limits its applicability for advanced engineering structure applications under harsh loading conditions. Therefore, it is necessary to further optimize the mechanical properties of CoCrNi multi-component alloys. In order to improve the yield strength of CoCrNi multi-component alloys, many strengthening means have been adopted, such as solid solution strengthening, grain refinement and precipitation strengthening, etc. These strengthening methods are conventional ways to effectively increase strength, but at the same time are accompanied by the sacrifice of ductility, and some even drop to 10-15%.
[0004] Introducing heterogeneous structures into alloys is an effective strengthening method, which can increase strength with a slight sacrifice of ductility. Heterogeneous structure materials have achieved unprecedented properties by controlling defect distribution, long-range internal stress and interaction between non-linear regions. Compared with traditional alloys, multi-component alloys have an advantage in regulating the formation of heterogeneous structures due to their huge composition space. This strength heterogeneity may be caused by differences in microstructure, crystal structure or composition. The inhomogeneity of multi-component alloys leads to effective heterogeneous deformation-induced strengthening, which can endow them with good strength-ductility synergy. Summary of the Invention
[0005] In view of this, the present invention proposes a multi-component alloy with both inhomogeneous grain sizes and heterogeneous L1 2High-strength and tough multi-component alloy with nano-phase and gradient σ-phase and its preparation method, to solve the problem that current multi-component alloys still need to develop to achieve good strength-ductility synergy effect.
[0006] To achieve the above object, in the first aspect of the present invention, a high-strength and tough multi-component alloy is provided, the structure of which contains a triple heterogeneous structure of non-uniform grain size, gradient σ-phase and heterogeneous L1 2 nano-precipitated phase; further, the microstructure of the high-strength and tough multi-component alloy is FCC phase and σ-phase;
[0007] On the basis of the above scheme, its chemical formula is Co 18 Cr 27 Ni 45 Al 10-x Mo x , and each component is composed according to the molar ratio of the chemical formula subscript, and x takes one of 2, 4 and 6. Preferably, in terms of atomic percentage content, it includes Co: 18 at.%, Cr: 27 at.%, Ni: 45 at.%, Al: 8 at.%, Mo: 2 at.%;
[0008] On the basis of the above scheme, the yield strength of the alloy is 471-1190 MPa, the ultimate tensile strength is 888-1314 MPa, and the elongation is 8.68-45.62%. Preferably, the yield strength of the alloy is 960 MPa, the ultimate tensile strength is 1194 MPa, and the elongation is 18.32%.
[0009] On the other hand, the present invention provides a preparation method of the above-mentioned high-strength and tough multi-component alloy, and the preparation method includes the following steps:
[0010] S1, mixing the raw materials and putting them into a copper mold crucible, vacuum arc melting under the protection of an argon atmosphere, and electromagnetic stirring to obtain an alloy ingot.
[0011] On the basis of the above scheme, preferably, S2, cutting and processing the obtained alloy ingot, and then carrying out homogenization treatment, water cooling, and cold rolling in an inert atmosphere to obtain a cold-rolled plate;
[0012] S3, annealing the obtained cold-rolled plate, and water cooling to obtain an annealed plate.
[0013] Based on the above solutions, preferably, in step S1: Select industrial pure cobalt, pure chromium, pure nickel, pure aluminum, and pure molybdenum millimeter-sized particles with a purity of ≥99.99%, and place them into a copper mold crucible for melting in ascending order of melting point from bottom to top; before the vacuum arc melting, evacuate the vacuum to below 8.0×10-4 Pa, then purge with argon twice, and finally melt the pure titanium ingot 3 times, with each time lasting at least 60 seconds; during the vacuum arc melting, under the protection of an argon atmosphere, melt at least 10 times repeatedly, the melting current is 350 - 500 A, and the arc duration for each melting is 3 - 4 minutes; after each component raw material melts into a liquid state, perform electromagnetic stirring, the electromagnetic stirring current is 10 - 20 A, and the duration for each time is 2 - 3 minutes.
[0014] Based on the above solutions, preferably, in step S2, the alloy ingot is processed by wire electrical discharge machining into a block with dimensions of 60×30×10 mm 3 Under an argon atmosphere, homogenize the alloy block at 1200 °C, cool it with water, and then perform cold rolling at 30 - 80 °C. The single pass reduction of the cold rolling is 0.2 mm, and the total reduction is 70% to obtain a cold-rolled sheet.
[0015] Based on the above solutions, preferably, in step S3, the annealing is first performed at 700 - 800 °C for 1 h, and then at 945 °C for 3 minutes.
[0016] The present invention has the following beneficial effects compared with the prior art:
[0017] 1) By selecting a specific alloy component ratio and combining vacuum arc melting, cold rolling, and heat treatment, the alloy obtained by the present invention mainly has two microstructures, namely the FCC phase with good toughness and the σ phase with excellent strength;
[0018] 2) The alloy structure prepared by the present invention also contains a triple heterogeneous structure of non-uniform grain size, gradient σ phase, and heterogeneous L1 2 nano-precipitation phase. This multiple heterogeneous structure can significantly improve the alloy strength while retaining the plasticity of the alloy, which is beneficial to achieving the strength-plasticity synergistic effect of the alloy;
[0019] 3) The annealing process of the preparation method of the present invention improves the overall performance of the alloy by regulating phase transformation and the volume fraction of each phase, plays a key role in balancing the strength and plasticity of the alloy, and realizes enhancing the alloy strength without sacrificing ductility too much. Description of the Drawings
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.
[0021] Figure 1 XRD patterns of the multi-component alloys prepared in Embodiments 1-3 of the present invention 18 Cr 27 Ni 45 Al 10-x Mo x XRD patterns of the multi-component alloys prepared in Embodiments 1-3 of the present invention
[0022] Figure 2 Room temperature tensile stress-strain curves of the multi-component alloys prepared in Embodiments 1-3 of the present invention 18 Cr 27 Ni 45 Al 10-x Mo x Room temperature tensile stress-strain curves of the multi-component alloys prepared in Embodiments 1-3 of the present invention
[0023] Figure 3 Phase diagrams of the multi-component alloys prepared in Embodiments 1-3 of the present invention 18 Cr 27 Ni 45 Al 10-x Mo x Phase diagrams of the multi-component alloys prepared in Embodiments 1-3 of the present invention
[0024] Figure 4 XRD patterns of the cold-rolled and annealed multi-component alloys prepared in Embodiment 6 of the present invention 18 Cr 27 Ni 45 Al 8 Mo 2 XRD patterns of the cold-rolled and annealed multi-component alloys prepared in Embodiment 6 of the present invention
[0025] Figure 5 Room temperature tensile stress-strain curves of the cold-rolled and annealed multi-component alloys prepared in Embodiment 6 of the present invention 18 Cr 27 Ni 45 Al 8 Mo 2 Room temperature tensile stress-strain curves of the cold-rolled and annealed multi-component alloys prepared in Embodiment 6 of the present invention
[0026] Figure 6 HRTEM, FFT and IFFT of the FCC phase in Sample 2 prepared in Embodiment 6 of the present invention Detailed implementation manners
[0027] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0028] Example 1:
[0029] Before vacuum arc melting, a furnace washing operation is required, that is, first evacuate the vacuum, then fill with argon, and then evacuate the vacuum again, and repeat the operation twice to completely remove the air at the end of the furnace pipeline and ensure that the vacuum degree in the furnace ≤ 8.0×10 -4 Pa.
[0030] In this embodiment, Co 18 Cr 27 Ni 45 Al 8 Mo 2 a multi-component alloy, that is, abbreviated as Mo2 alloy for short, the preparation method is: use an electronic balance to weigh 19.24 g of industrial pure cobalt millimeter-sized particles with a purity ≥ 99.99%, 25.46 g of pure chromium millimeter-sized particles, 47.90 g of pure nickel millimeter-sized particles, 3.92 g of pure aluminum millimeter-sized particles, and 3.48 g of pure molybdenum millimeter-sized particles respectively, and put them into a copper mold crucible in ascending order of melting point from bottom to top and melt repeatedly for 10 times. First evacuate the vacuum and then fill with argon to ensure that the vacuum degree in the furnace ≤ 8.0×10 -4 Pa.
[0031] During the melting process, the melting current is 350 - 500 A, and the arc lasts for 3 - 4 minutes each time. After each component raw material is melted into a liquid state, electromagnetic stirring is carried out. The electromagnetic stirring current is 10 - 20 A, and the duration of each time is 2 - 3 minutes. Finally, slowly return the current to zero and cool it.
[0032] Example 2:
[0033] The operation steps of this embodiment are the same as those of Example 1, but the differences are:
[0034] In this embodiment, Co 18 Cr 27 Ni 45 Al 6 Mo 4 a multi-component alloy, that is, abbreviated as Mo4 alloy for short, the preparation method is: use an electronic balance to weigh 18.77 g of industrial pure cobalt millimeter-sized particles with a purity ≥ 99.99%, 24.84 g of pure chromium millimeter-sized particles, 46.73 g of pure nickel millimeter-sized particles, 2.87 g of pure aluminum millimeter-sized particles, and 6.79 g of pure molybdenum millimeter-sized particles respectively.
[0035] Example 3:
[0036] This example has the same operation steps as Example 1, but the differences are as follows:
[0037] This example prepares Co 18 Cr 27 Ni 45 Al 4 Mo 6 a multi-component alloy, namely abbreviated as Mo6 alloy. The preparation method is: use an electronic balance to weigh 18.32 g of industrial pure cobalt millimeter-sized particles with a purity ≥ 99.99%, 24.25 g of pure chromium millimeter-sized particles, 45.62 g of pure nickel millimeter-sized particles, 1.87 g of pure aluminum millimeter-sized particles, and 9.94 g of pure molybdenum millimeter-sized particles respectively.
[0038] Example 4:
[0039] This example has the same operation steps as Example 1, but the differences are as follows:
[0040] This example prepares Co 18 Cr 27 Ni 45 Al 10 a multi-component alloy, namely abbreviated as Mo0 alloy. The preparation method is: use an electronic balance to weigh 19.73 g of industrial pure cobalt millimeter-sized particles with a purity ≥ 99.99%, 26.12 g of pure chromium millimeter-sized particles, 49.12 g of pure nickel millimeter-sized particles, and 5.02 g of pure aluminum millimeter-sized particles respectively. The alloy phase is composed of FCC phase and B2 phase, and the B2 phase is a brittle intermetallic compound phase. Here, due to the excessive ratio of Ni and Al in the alloy, NiAl intermetallic compound with B2 structure is formed, which will significantly reduce the mechanical properties of the alloy.
[0041] Example 5:
[0042] This example has the same operation steps as Example 1, but the differences are as follows:
[0043] This example prepares Co 18 Cr 27 Ni 45 Mo 10 a multi-component alloy, namely abbreviated as Mo10 alloy. The preparation method is: use an electronic balance to weigh 17.49 g of industrial pure cobalt millimeter-sized particles with a purity ≥ 99.99%, 23.15 g of pure chromium millimeter-sized particles, 43.54 g of pure nickel millimeter-sized particles, and 15.82 g of pure molybdenum millimeter-sized particles respectively. The alloy phase is composed of FCC phase and σ phase. Here, no L1 2 nano-phase precipitates in the alloy. The reason is that the structure of the L1 2 nano-precipitation phase is Ni 3Al. When the Ni / Al ratio in the alloy is too low or when the Al element is absent, the L1 nano-phase will not precipitate in the alloy. At the same time, too high a content of the σ-phase will also reduce the mechanical properties of the alloy. 2
[0044] The phase structures and mechanical properties of the multi-component alloys in Examples 1 - 3 above were characterized, and the test information is as follows:
[0045] 1) Phase analysis: The phase composition of the alloys obtained in Examples 1 - 3 was characterized using an X-ray diffractometer (XRD). The 2θ scanning range was 20° - 100°, and the scanning speed was 5° / min. The results are as Figure 1 shown: It can be seen that Co 18 Cr 27 Ni 45 Al 10-x Mo x All the multi-component alloys are face-centered cubic alloys, and no precipitation phase is generated inside. However, as the content of the Mo element increases, the (111) diffraction peak shifts towards a lower angle, indicating a significant lattice distortion inside the alloy.
[0046] 2) Mechanical properties: An electronic universal tensile testing machine was used to conduct room-temperature tensile tests on the multi-component alloys prepared in Examples 1 - 3. The tensile samples were plate-shaped specimens with dimensions of 46×8×2 mm 3 , and the strain rate was 1×10 -3 s -1 . At least three specimens were tested for each sample to avoid accidental test results. The results are as Figure 2 and Table 1 show:
[0047] Table 1 Room-temperature tensile mechanical properties of the multi-component alloys of cast Co 18 Cr 27 Ni 45 Al 10-x Mo x
[0048]
[0049] It can be seen that the cast Co 18 Cr 27 Ni 45 Al 10-x Mo x multi-component alloys have excellent mechanical properties at room temperature, with a yield strength not lower than 264 MPa, a tensile strength not lower than 591 MPa, and an elongation not lower than 54.4%. In particular, for the Co 18 Cr 27 Ni 45 Al 8 Mo 2The alloy exhibits good comprehensive mechanical properties.
[0050] 3) Phase diagram analysis: The Pandat phase diagram software was used to calculate the phase diagrams of the multi-component alloys prepared in Examples 1-3. The theoretical calculation results of the phase diagrams are as Figure 3 shown. It can be seen that when the alloy is quenched at 700-800 °C, its phase composition is FCC + σ + L1 2 phase; when the alloy is quenched at 800-900 °C, its phase composition is FCC + L1 2 phase; when the alloy is quenched at 900 °C, its phase composition is a single-phase FCC structure. In addition, it should be noted here that if the annealing temperature is lower than 700 °C, a large amount of σ phase will precipitate, and the σ phase is a brittle intermetallic compound phase. Excessive precipitation of the σ phase will reduce the mechanical properties of the alloy.
[0051] Example 6:
[0052] Taking the multi-component alloy prepared in Example 1 as the object, the alloy ingot was processed into a block with dimensions of 60×30×10 mm by wire electrical discharge machining 3 and then, in an argon atmosphere, the alloy block was homogenized at 1200 °C for 24 h, water-cooled, and then cold-rolled at 30-80 °C with a single pass reduction of 0.2 mm and a total reduction of 70% to obtain a cold-rolled sheet. Then, in an argon atmosphere, three groups of samples were taken from the cold-rolled sheet and annealed under different processes:
[0053] Sample 1: First annealed at 700 °C for 1 h, and then annealed at 945 °C for 3 min;
[0054] Sample 2: First annealed at 750 °C for 1 h, and then annealed at 945 °C for 3 min;
[0055] Sample 3: First annealed at 800 °C for 1 h, and then annealed at 945 °C for 3 min;
[0056] Sample 4: Only annealed at 1000 °C for 1 h;
[0057] All samples were water-cooled after annealing to obtain annealed sheets.
[0058] The phase structure, microstructure, and mechanical properties of the multi-component alloy obtained in Example 6 were characterized, and the test information is as follows:
[0059] 1) Phase analysis: An X-ray diffractometer (XRD) was used to characterize the phase composition of the multi-component alloy obtained in Example 6. The 2θ scanning range was 20°-100°, and the scanning speed was 5° / min. The results are as Figure 4 shown: It can be seen that after cold rolling and annealing, Co 18 Cr 27Ni 45 Al 8 Mo 2 The multi-component alloy phase is composed of FCC phase and σ phase.
[0060] 2) Mechanical properties: Using an electronic universal tensile testing machine, the multi-component alloy prepared in Example 6 was subjected to tensile testing at room temperature. The tensile sample was a plate-shaped specimen of 46×8×2 mm 3 at a strain rate of 1×10 -3 s -1 . At least three specimens were tested for each sample to avoid accidental test results. The results are as Figure 5 shown in Table 2:
[0061] Table 2 Co after cold rolling and annealing 18 Cr 27 Ni 45 Al 8 Mo 2 Room temperature tensile mechanical properties of the multi-component alloy
[0062]
[0063] It can be seen that Co 18 Cr 27 Ni 45 Al 8 Mo 2 The multi-component alloy has more excellent mechanical properties at room temperature. Especially, the alloy of Sample 2 shows the best comprehensive mechanical properties, with a yield strength of 960 MPa, an ultimate tensile strength of 1194 MPa, and an elongation of 18.32%, achieving a good combination of strength and plasticity.
[0064] 3) Microstructure: The microstructure of Sample 2 in Example 6 was characterized by transmission electron microscopy (TEM). The results are as Figure 6 shown. It can be seen that L1 2 type superlattice spots appear in the FCC phase. To further analyze the distribution of the L1 2 phase, by masking the {110} and {100} type superlattice diffraction spots in the FFT image and creating an IFFT image, different-sized ordered L1 2 phases precipitated in the FCC phase can be clearly observed from the IFFT image.
[0065] From the comparison of Examples 1 to 6 above, it can be seen that the alloy of Sample 2 achieved a strength-plasticity synergistic effect, with a yield strength of 960 MPa, an ultimate tensile strength of 1194 MPa, and an elongation of 18.32%. At the same time, the microstructure also contains non-uniform grain sizes, gradient σ phases, and heterogeneous L1 2The triple heterostructure of nano-precipitates can provide ideas for realizing the strength-ductility synergy effect of metallic materials.
[0066] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A high-strength and tough multi-component alloy, characterized in that: Its chemical formula is Co 18 Cr 27 Ni 45 Al 10-x Mo x , the components are composed according to the molar ratio of the subscripts of the chemical formula, and x is one of 2, 4 and 6.
2. A high-strength and tough multi-component alloy as claimed in claim 1, characterized in that: Its microstructure contains a triple heterogeneous structure of uneven grain size, gradient σ phase and heterogeneous L12 nano-precipitation phase.
3. The high-strength and tough multi-component alloy according to claim 1, characterized in that: The alloy has a yield strength of 471-1190 MPa, an ultimate tensile strength of 888-1314 MPa, and an elongation of 8.68-45.62%.
4. The method for preparing a high-strength and tough multi-component alloy according to claim 1, characterized in that The preparation method comprises the following steps: S1, mix the raw materials and put them into a copper mold crucible, and perform vacuum arc melting and electromagnetic stirring under the protection of argon atmosphere to obtain an alloy ingot.
5. The method for preparing a high-strength and tough multi-component alloy according to claim 4, characterized in that The preparation method comprises the following steps: S2, cutting the obtained alloy ingot, and then homogenizing it in an inert atmosphere, water cooling it, and cold rolling it to obtain a cold-rolled sheet; S3, annealing the obtained cold-rolled sheet, and water cooling to obtain an annealed sheet.
6. The preparation method according to claim 4, characterized in that: In step S1: Before vacuum arc melting, the vacuum degree is drawn to 8.0×10 -4 Pa, then fill with argon gas for purging twice, and finally melt the pure titanium ingot three times, each time for at least 60 seconds.
7. The preparation method according to claim 4, characterized in that: In step S1: During the vacuum arc melting, the melting is performed at least 10 times under the protection of an argon atmosphere, the melting current is 350-500A, and each melting arc lasts for 3-4 minutes.
8. The preparation method according to claim 4, characterized in that: In step S1: The electromagnetic stirring is performed after each of the component raw materials is melted into a liquid state. The electromagnetic stirring current is 10-20A and the duration of each stirring is 2-3 minutes.
9. The preparation method according to claim 5, characterized in that: In step S2, the cold rolling temperature is 30-80°C, the single pressing amount is 0.2 mm, and the total pressing amount is 70%.
10. The preparation method according to claim 5, characterized in that: In step S3, the annealing is first annealing at 700-800° C. for 1 hour, and then annealing at 945° C. for 3 minutes.