A high-performance dual-phase nanostructured high-entropy alloy material and its preparation method

Abstract

This invention belongs to the field of alloy materials technology, specifically disclosing a high-performance dual-phase nanostructure high-entropy alloy material and its preparation method. The chemical formula of the high-entropy alloy is FeNiCrSiAl, comprising the following atomic percentage raw materials: Fe 34-44%, Ni 32-42%, Cr 3-13%, Si 3-13%, and Al 3-13%. This invention utilizes the aforementioned high-performance dual-phase nanostructure high-entropy alloy material and its preparation method, using inexpensive elements such as Fe and Cr as the main matrix, replacing traditional high-cost metals such as Co and Ti. While reducing costs, it constructs a microstructure with synergistic soft / hard dual-phase reinforcement, overcoming the strength-plasticity inversion effect, and exhibiting high yield strength, tensile strength, and ductility.

Description

Technical Field

[0001] This invention relates to the field of alloy materials technology, and in particular to a high-performance dual-phase nanostructure high-entropy alloy material and its preparation method. Background Technology

[0002] High-entropy alloys (HEAs), as multi-principal-element systems that break through traditional alloy design concepts, have become a research hotspot in the field of advanced metallic materials due to their unique solid solution structure and excellent strength, toughness, corrosion resistance, and thermal stability. Early research mainly focused on single-phase high-entropy alloy systems (such as typical Co-Cr-Fe-Mn-Ni alloys), but the prevalent strength-plasticity inversion effect severely restricts the synergistic improvement of comprehensive mechanical properties in engineering applications.

[0003] To address the aforementioned bottlenecks, dual-phase high-entropy alloys have demonstrated significant technological advantages through the construction of multiphase coupled structures. Dual-phase high-entropy alloy systems, represented by Cr-Fe-Co-Ni based alloys (such as Cr-Fe-Co-Ni-Al and Cr-Mn-Fe-Co-Ni-Al), have achieved breakthroughs in balancing strength and ductility. However, existing systems face dual constraints: firstly, the high content of precious metal elements (such as Co) significantly increases material costs compared to traditional alloys; secondly, traditional preparation processes are limited by a narrow composition control window, resulting in a significant gap between the phase structure stability and the requirements of industrial production.

[0004] Therefore, overcoming the bottlenecks of existing dual-phase high-entropy alloys, such as strong dependence on precious metals and poor process adaptability, and developing new alloy systems that combine low cost, wide process window and controllable mechanical properties, and establishing preparation technology pathways suitable for large-scale production, has become the core research direction for promoting the industrial application of high-entropy alloys. Summary of the Invention

[0005] The purpose of this invention is to provide a high-performance dual-phase nanostructured high-entropy alloy material and its preparation method. The chemical formula of this novel high-entropy alloy is FeNiCrSiAl. It uses inexpensive elements such as Fe and Cr as the main matrix to replace traditional high-cost metals such as Co and Ti. While reducing costs, it constructs a microstructure with soft / hard dual-phase synergistic reinforcement, overcomes the strength-plasticity inversion effect, and has high yield strength, tensile strength and ductility.

[0006] To achieve the above objectives, this invention provides a high-performance dual-phase nanostructure high-entropy alloy material. The chemical formula of the high-entropy alloy is FeNiCrSiAl, which includes the following atomic percentage raw materials: Fe 34-44%, Ni 32-42%, Cr 3-13%, Si 3-13%, and Al 3-13%.

[0007] Preferably, the high-entropy alloy comprises the following atomic percentage raw materials: Fe 39%, Ni 37%, Cr 8%, Si 8%, and Al 8%.

[0008] Preferably, the purity of Fe, Ni, Cr, Si, and Al is 99.99%.

[0009] Preferably, the high-entropy alloy is composed of face-centered cubic and body-centered cubic phases, and granular body-centered cubic phases are precipitated in the face-centered cubic phases and fibrous face-centered cubic phases are precipitated in the body-centered cubic phases.

[0010] This invention also provides a method for preparing high-performance dual-phase nanostructured high-entropy alloy materials, comprising the following steps:

[0011] Step 1, Raw material pretreatment: Weigh the raw materials according to atomic percentage, mix them evenly, and press the mixed raw materials into cylinders;

[0012] Step 2, Vacuum Arc Melting: Place the pretreated alloy cylinder into the arc melting crucible, then evacuate the vacuum arc furnace, and then fill it with protective gas to atmospheric pressure. Melting is carried out under the protective gas atmosphere.

[0013] Step 3, alloy suction casting: The molten alloy liquid is sucked into a water-cooled copper mold to cool and form a high-entropy alloy plate;

[0014] Step 4, Homogenization treatment: The cast high-entropy alloy plate is placed in a box-type resistance furnace and held at 1150℃ for 4 hours before being water-quenched and cooled.

[0015] Step 5, Rolling: The homogenized high-entropy alloy sheet is rolled at room temperature;

[0016] Step 6, Annealing: Place the rolled high-entropy alloy sheet in a box-type resistance furnace, hold it at 800-1000℃ for 2 minutes, and then cool it with water to complete the preparation of the face-centered cubic / body-centered cubic dual-phase nanostructure high-entropy alloy.

[0017] Preferably, in step 2, the current intensity of vacuum arc melting is 250A and the voltage is 28.5V, and each alloy cylinder is repeatedly flipped and melted 4 times.

[0018] Preferably, in step 5, the rolling direction is along the width direction of the high-entropy alloy sheet, and the reduction is 90%.

[0019] The advantages and beneficial effects of the above-mentioned high-performance dual-phase nanostructure high-entropy alloy material and its preparation method are as follows:

[0020] 1. Single-phase high-entropy alloys exhibit superior performance in certain properties. For example, high-entropy alloys with a single FCC (face-centered cubic) phase are known for their excellent ductility, but their strength is relatively weak. In contrast, high-entropy alloys with a single BCC (body-centered cubic) phase are the opposite. Two-phase high-entropy alloys cleverly combine the advantages of both structures, achieving a synergistic improvement in both strength and ductility. Furthermore, the increased content of the low-cost element Fe, and the absence of precious metals such as Co and V, reduces the raw material costs for preparing two-phase nanostructured high-entropy alloys, achieving a cost-effectiveness balance.

[0021] 2. This invention effectively improves the microstructure through the synergistic effect of alloy composition design and specific processes, refines the grain structure, and forms a unique dual-phase nanostructure. The FCC and BCC phases precipitate into each other. While the FCC phase undergoes grain refinement, granular BCC phase precipitates, while fibrous FCC phase precipitates in the BCC phase. This microstructure enables the dual-phase nanostructure high-entropy alloy prepared by this invention to overcome the strength-plasticity inversion effect.

[0022] 3. The dual-phase nanostructured high-entropy alloy prepared by this invention has excellent comprehensive mechanical properties, with a yield strength ranging from approximately 1040 to 1580 MPa, a tensile strength ranging from approximately 1370 to 1710 MPa, and an elongation after fracture of 18-29%. The preparation method is simple to operate, highly stable, and conducive to large-scale application.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a flowchart of the heat treatment and rolling process of the present invention;

[0025] Figure 2 The room temperature tensile stress-strain curves of the biphase nanostructured high-entropy alloys prepared in Examples 1, 2, and 3 of this invention and Comparative Example 1 are shown.

[0026] Figure 3 SEM images of the biphase nanostructured high-entropy alloys prepared in Examples 1, 2, and 3 and Comparative Example 1 of the present invention are shown, where A is Example 1, B is Example 2, C is Example 3, and D is Comparative Example 1.

[0027] Figure 4 The image shows the XRD pattern of the dual-phase nanostructured high-entropy alloy prepared in Example 1 of this invention.

[0028] Figure 5 The image shows the EDS diagrams of the FCC and BCC phases in the dual-phase nanostructured high-entropy alloy prepared in Example 1 of this invention. In the diagram, A represents the precipitation of granular BCC within the FCC sheets, and B represents the precipitation of fibrous FCC within the BCC sheets. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0031] Unless otherwise defined, all reagents, equipment and other materials used in this invention are commercially available.

[0032] Example 1

[0033] A high-performance dual-phase nanostructure high-entropy alloy material, the chemical formula of which is FeNiCrSiAl, comprises the following atomic percentage raw materials: Fe: 39%, Ni: 37%, Cr: 8%, Si: 8%, and Al: 8%.

[0034] The purity of Fe, Ni, Cr, Si, and Al is 99.99%.

[0035] High-entropy alloys are composed of face-centered cubic (FCC) and body-centered cubic (BCC) phases, with granular body-centered cubic phases precipitating in the FCC phase and fibrous face-centered cubic phases precipitating in the BCC phase.

[0036] A method for preparing a high-performance dual-phase nanostructured high-entropy alloy material includes the following steps:

[0037] Step 1, Raw material pretreatment: Weigh out elemental metal powder with a purity of 99.99% according to the atomic percentages of Fe: 39%, Ni: 37%, Cr: 8%, Si: 8%, and Al: 8%. Mix the metal powder (mixing method: the powder is mechanically mixed evenly, or the raw materials can be used in blocks without mechanical mixing). Press the mixed powder into a cylinder with a diameter of 14 mm and a length of 20 mm.

[0038] Step 2, Vacuum Arc Melting: Place the alloy cylinder into the arc melting crucible, then evacuate the vacuum arc furnace, and then fill it with argon gas to atmospheric pressure. Melting is carried out in the argon atmosphere. The arc melting current is 250A and the voltage is 28.5V. Each alloy cylinder is repeatedly turned and melted 4 times to ensure compositional uniformity.

[0039] Step 3, alloy suction casting: The molten alloy liquid is sucked into a water-cooled copper mold to cool and form a high-entropy alloy plate with a size of 120×12×8mm.

[0040] Step 4, Homogenization treatment: The cast high-entropy alloy plate is placed in a box-type resistance furnace for homogenization treatment, and then held at 1150℃ for 4 hours before being water quenched and cooled.

[0041] Step 5, Rolling: The homogenized high-entropy alloy sheet is rolled at room temperature along the 12mm direction of the high-entropy alloy sheet, with a reduction of 90%.

[0042] Step 6, Annealing: The rolled high-entropy alloy sheet is placed in a box-type resistance furnace for annealing. After holding at 900℃ for 2 minutes, it is cooled by water quenching, thus completing the preparation of low-cost, high-performance dual-phase nanostructure high-entropy alloy.

[0043] The process flow for preparing the dual-phase nanostructured high-entropy alloy in Example 1 is as follows: Figure 1 As shown.

[0044] A room temperature tensile test was conducted on the dual-phase nanostructured high-entropy alloy prepared in Example 1, and the results are as follows: Figure 2 As shown. SEM analysis was performed on the dual-phase nanostructured high-entropy alloy prepared in Example 1, and the results are as follows. Figure 3 As shown. XRD experiments were performed on the dual-phase nanostructured high-entropy alloy prepared in Example 1, and the results are as follows. Figure 4 As shown. EDS testing was performed on the dual-phase nanostructured high-entropy alloy prepared in Example 1, and the results are as follows. Figure 5 As shown.

[0045] Example 2

[0046] Alloy samples were prepared using the same method as in Example 1, except that the annealing temperature in this example was 800°C, and the samples were held at this temperature for 2 minutes before being quenched in water.

[0047] A room temperature tensile test was conducted on the dual-phase nanostructured high-entropy alloy prepared in Example 2, and the results are as follows: Figure 2 As shown; SEM analysis was performed on the dual-phase nanostructured high-entropy alloy prepared in Example 2, and the results are as follows. Figure 3 As shown.

[0048] Example 3

[0049] Alloy samples were prepared using the same method as in Example 1, except that the annealing temperature in this example was 1000°C, and the samples were held at this temperature for 2 minutes before being quenched in water.

[0050] A room temperature tensile test was conducted on the dual-phase nanostructured high-entropy alloy prepared in Example 3. The results are as follows: Figure 2 As shown; SEM tests were performed on the dual-phase nanostructured high-entropy alloy prepared in Example 3, and the results are as follows. Figure 3 As shown.

[0051] Example 4

[0052] A high-performance dual-phase nanostructure high-entropy alloy material, the chemical formula of which is FeNiCrSiAl, comprises the following atomic percentage raw materials: Fe: 34%, Ni: 40%, Cr: 10%, Si: 5%, and Al: 13%. The rest is the same as in Example 1.

[0053] Example 5

[0054] A high-performance dual-phase nanostructure high-entropy alloy material, the chemical formula of which is FeNiCrSiAl, comprises the following atomic percentage raw materials: Fe: 43%, Ni: 32%, Cr: 4%, Si: 11%, and Al: 4%. The rest is the same as in Example 1.

[0055] Comparative Example 1

[0056] High-entropy alloy materials were prepared using the following method:

[0057] 1. Weigh out elemental metal powder with a purity of 99.99% according to atomic percentages: Fe:39%, Ni:37%, Cr:8%, Si:8%, and Al:8%. Mix the metal powder (mixing method: the powder is mechanically mixed evenly; the raw materials can also be used in bulk without mechanical mixing). Press the mixed powder into a cylinder with a diameter of 14 mm and a length of 20 mm.

[0058] 2. Place the alloy cylinder into the electric arc melting crucible, then evacuate the vacuum electric arc furnace, and then fill it with argon gas to atmospheric pressure. Melt under the argon atmosphere. The electric arc melting current is 250A and the voltage is 28.5V. Each alloy ingot is repeatedly turned over and melted 4 times to ensure the uniformity of composition.

[0059] 3. The molten alloy liquid after melting is drawn into a water-cooled copper mold to cool and form a high-entropy alloy plate with a casting size of 120×12×8mm.

[0060] 4. The cast high-entropy alloy plate is placed in a box-type resistance furnace for homogenization treatment, and then held at 1150℃ for 4 hours before being water-quenched.

[0061] 5. The homogenized high-entropy alloy sheet is rolled at room temperature, with the rolling direction along the 12mm direction of the sheet and a reduction of 90%.

[0062] The high-entropy dual-phase nanostructure alloy prepared in Comparative Example 1 was subjected to a room temperature tensile test, and the results are as follows: Figure 2 As shown; the dual-phase nanostructured high-entropy alloy prepared in Example 1 was subjected to SEM testing, and the results are as follows. Figure 3 As shown.

[0063] pass Figure 2 It can be seen that the room temperature tensile properties of Comparative Example 1 are relatively poor, while Examples 1, 2, and 3 all exhibit superior room temperature tensile properties. Among them, the dual-phase nanostructured high-entropy alloy prepared in Example 1 has the best comprehensive mechanical properties, with a yield strength of approximately 1460 MPa, a tensile strength of approximately 1650 MPa, and an elongation after fracture of 27%. Therefore, it can be seen that the control of the annealing temperature in the preparation process of this invention can optimize the comprehensive mechanical properties of the dual-phase nanostructured high-entropy alloy.

[0064] pass Figure 3 and Figure 4 It can be seen that Examples 1, 2, 3 and Comparative Example 1 all contain both FCC and BCC phases at different annealing temperatures, but exhibit different microstructures. In the high-entropy alloy prepared in Example 1, the grains are significantly refined, forming a unique two-phase nanostructure. A large amount of FCC phase precipitates in the BCC phase, and the precipitated FCC phases are interwoven. Therefore, the control of the annealing temperature in the preparation process of this invention can also construct unique two-phase nanostructures.

[0065] pass Figure 5 It can also be seen that in the dual-phase nanostructured high-entropy alloy prepared in Example 1, the FCC phase undergoes grain refinement, and granular BCC phase precipitates at the same time. In the BCC phase, fibrous FCC phase precipitates. The mutual precipitation between the FCC and BCC phases will hinder dislocation movement through precipitation strengthening mechanism, thereby improving the yield strength of the high-entropy alloy. In addition, the difference in deformation behavior between the FCC and BCC phases leads to strain distribution, and the overall plasticity is improved through multi-phase coordinated deformation.

[0066] Compared to Comparative Example 1, Example 1 added homogenization, rolling, and annealing processes, improving the composition and structure of the FCC and BCC phases and refining the grain structure, thereby enhancing the overall performance of the material. Compared to Examples 2 and 3, Example 1 optimized the preparation process of the high-entropy alloy. By changing the holding temperature during the annealing process, a unique two-phase nanostructure was constructed, achieving mutual precipitation between the FCC and BCC phases and overcoming the strength-plasticity inversion effect. The two-phase nanostructure high-entropy alloy prepared in Example 1 exhibits excellent comprehensive mechanical properties, with a yield strength of approximately 1460 MPa, a tensile strength of approximately 1650 MPa, and an elongation after fracture of 27%. The two-phase nanostructure high-entropy alloy prepared using the composition and method provided by this invention possesses a unique microstructure, as well as high strength and excellent plasticity.

[0067] Therefore, this invention employs the above-mentioned high-performance dual-phase nanostructure high-entropy alloy material and its preparation method. The chemical formula of this novel high-entropy alloy is FeNiCrSiAl. It uses inexpensive elements such as Fe and Cr as the main matrix, replacing traditional high-cost metals such as Co and Ti. While reducing costs, it constructs a microstructure with soft / hard dual-phase synergistic reinforcement, breaks through the strength-plasticity inversion effect, and has high yield strength, tensile strength and ductility.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-performance dual-phase nanostructure high-entropy alloy material, characterized in that, The chemical formula for high-entropy alloys is FeNiCrSiAl, which includes the following atomic percentage raw materials: Fe 34-44%, Ni 32-42%, Cr 3-13%, Si 3-13%, and Al 3-13%. A method for preparing high-performance dual-phase nanostructured high-entropy alloy materials includes the following steps: Step 1, Raw material pretreatment: Weigh the raw materials according to atomic percentage, mix them evenly, and press the mixed raw materials into cylinders; Step 2, Vacuum Arc Melting: Place the pretreated alloy cylinder into the arc melting crucible, then evacuate the vacuum arc furnace, and then fill it with protective gas to atmospheric pressure. Melting is carried out under the protective gas atmosphere. Step 3, alloy suction casting: The molten alloy liquid is sucked into a water-cooled copper mold to cool and form a high-entropy alloy plate; Step 4, Homogenization treatment: The cast high-entropy alloy plate is placed in a box-type resistance furnace and held at 1150℃ for 4 hours before being water-quenched and cooled. Step 5, Rolling: The homogenized high-entropy alloy sheet is rolled at room temperature; Step 6, Annealing: Place the rolled high-entropy alloy sheet in a box-type resistance furnace, hold it at 800-1000℃ for 2 minutes, and then cool it with water to complete the preparation of the face-centered cubic / body-centered cubic dual-phase nanostructure high-entropy alloy.

2. The high-performance dual-phase nanostructure high-entropy alloy material according to claim 1, characterized in that: The high-entropy alloy comprises the following atomic percentage raw materials: Fe 39%, Ni 37%, Cr 8%, Si 8%, and Al 8%.

3. The high-performance dual-phase nanostructure high-entropy alloy material according to claim 1, characterized in that: The purity of Fe, Ni, Cr, Si, and Al is 99.99%.

4. The high-performance dual-phase nanostructure high-entropy alloy material according to claim 1, characterized in that: High-entropy alloys are composed of face-centered cubic and body-centered cubic phases, with granular body-centered cubic phases precipitating in the face-centered cubic phase and fibrous face-centered cubic phases precipitating in the body-centered cubic phase.

5. The high-performance dual-phase nanostructure high-entropy alloy material according to claim 1, characterized in that: In step 2, the current intensity of vacuum arc melting is 250A and the voltage is 28.5V. Each alloy cylinder is repeatedly flipped and melted 4 times.

6. The high-performance dual-phase nanostructure high-entropy alloy material according to claim 1, characterized in that: In step 5, the rolling direction is along the width of the high-entropy alloy sheet, and the reduction is 90%.

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