A multi-principal element alloy / magnesium alloy bimetallic material and its preparation method

Abstract

The present invention discloses a multi-principal element alloy / magnesium alloy bimetallic material and a preparation method thereof, including a multi-principal element alloy and a magnesium alloy; the multi-principal element alloy is selected from alloys such as AlCoCrFeNi series, AlBeFeSiTi series, AlCrFeMnTi series, AlCrTiV series, etc., and GdTbHoEr(La, Y) series rare earth high-entropy alloys and (CoCrNi) l00‑x Al x series, ErHoTb series alloys, the magnesium alloy includes a cast magnesium alloy and a wrought magnesium alloy, and also includes surface active elements. In the present invention, the multi-principal element alloy contains magnesium element or elements with high solubility or high diffusivity in magnesium. High-temperature heat treatment forms a solute supersaturated transition layer at the interface between the multi-principal element alloy and the magnesium alloy, and low-temperature heat treatment precipitates nano-precipitates in the transition layer, strengthening the interface between the multi-principal element alloy and the magnesium alloy, so that the bimetallic material has good overall mechanical properties and interface bonding strength.

Description

Technical Field

[0001] The present invention belongs to the field of bimetallic materials, and relates to a multi-principal element alloy / magnesium alloy bimetallic material and a preparation method thereof. Background Art

[0002] In modern industries such as aerospace, transportation, instrumentation, military, and automobiles, the components involved tend to be integrated, which may require significantly different properties in different parts of the same structural member. For example, it is required that the surface of the component has good wear resistance while the center has good toughness. Conventional single materials are not effective in solving the above problems. In contrast, by combining two materials with different properties, the performance advantages of the two materials can be exerted, so as to better meet the specific property requirements of different parts of the same component. Among them, the key lies in developing bimetallic materials with excellent properties.

[0003] The matrix material is the fundamental factor determining the properties of bimetallic materials, and the interface is the most critical part determining the properties of bimetallic materials. Magnesium alloys have the advantages of high specific strength, low density, excellent damping performance, etc., and are widely used in the preparation of bimetallic materials. At present, there have been a large number of reports on the formation of bimetallic materials by combining metals such as aluminum, steel, titanium, and lead with magnesium. Some reports are dedicated to directly combining these materials with magnesium alloys. However, due to the poor interfacial wettability between these metals and magnesium alloys, it is difficult to form a good metallurgical bond. At the same time, brittle intermetallic compounds are easily formed at the interface, making the interface inevitably become the weak link in the material fracture process, with low interface strength, thus resulting in poor overall performance of the bimetallic material. Moreover, the elastic modulus and linear expansion coefficient of these metals and magnesium alloys differ greatly, making obvious stress concentration easily occur at the interface, leading to the easy initiation and propagation of cracks at the interface. To improve the bonding ability between these metals and magnesium alloys, the commonly adopted strategy is to introduce a transition layer between the two metals, which greatly complicates the preparation process of bimetallic materials and increases the preparation cost of bimetallic materials.

[0004] Compared with traditional alloys, multi-principal element alloys have excellent mechanical properties, good wear resistance, and a large elastic strain limit. Combining them with magnesium to form a bimetallic material is expected to achieve better comprehensive properties and has broad application prospects. However, there are few reports on multi-principal element alloy / magnesium alloy bimetallic materials and their preparation processes. Since not all multi-principal element alloys and magnesium matrices have good interfacial wettability and interfacial compatibility, therefore: (1) It is necessary to screen appropriate multi-principal element alloy systems to meet the wettability and compatibility between multi-principal element alloys and magnesium alloys, and ensure good metallurgical bonding can be directly achieved without the aid of an intermediate layer; (2) On the premise of selecting a suitable multi-principal element alloy system, other means still need to be supplemented to further improve the wettability and compatibility between multi-principal element alloys and magnesium alloys, reduce the stress concentration at the interface between multi-principal element alloys and magnesium alloys, and improve the ability of the interface between multi-principal element alloys and magnesium alloys to resist deformation and damage, so as to maximize the performance of the bimetallic material, which is rarely involved in existing reports. Summary of the Invention

[0005] To overcome the deficiencies of the prior art, the purpose of the present invention is to provide a multi-principal element alloy / magnesium alloy bimetallic material and its preparation method. The selected multi-principal element alloy contains magnesium elements or elements with high solubility or high diffusion ability in magnesium, ensuring intrinsic interfacial compatibility between the multi-principal element alloy and the magnesium alloy. Surface-active elements are added to further improve the wettability of the multi-principal element alloy / magnesium alloy interface, promote the metallurgical bonding of the two alloys, and form a solute supersaturated transition layer at the interface between the multi-principal element alloy and the magnesium alloy through subsequent high-temperature heat treatment, and avoid the formation of brittle intermetallic compounds, improve the wettability and compatibility between the multi-principal element alloy and the magnesium alloy interface, relieve the stress concentration at the interface, and precipitate nano-precipitates in the above transition layer through subsequent low-temperature heat treatment to further strengthen the interface between the multi-principal element alloy and the magnesium alloy, so that the bimetallic material has good overall mechanical properties and interfacial bonding strength.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention provides a multi-principal element alloy / magnesium alloy bimetallic material, which includes a multi-principal element alloy and a magnesium alloy;

[0008] The constituent elements of the multi-principal element alloy contain magnesium elements, or elements with a certain solubility in magnesium (maximum solubility ≥ 1%), or elements with strong diffusion ability in magnesium, and are selected from the AlCoCrFeNi system, the AlBeFeSiTi system, the AlCrFeMnTi system, the AlCrTiV system, Mg x (MnAlZnCu) 100-xHigh-entropy alloys of AlCoCrFeNi system, AlMgZnCuSi system, AlLiMgZnCu system, AlLiMgZnSn system, AlLiMgScTi system, AlNbTiV system, AlFeMgTiZn system, AlLiMgCaSi system, AlCuCrFeSi system, AlCaCuNiSiTi system, rare-earth high-entropy alloys of DyGdLuTbTm system, DyGdLuTbY system, SmEuTbDyLu system, ErHoGdNiCo system, GdTbHoEr(La, Y) system, and (CoCrNi) l00-x Al x system and one or more combinations of alloys of ErHoTb system, where x = 0 - 30%;

[0009] The magnesium alloy includes cast magnesium alloy and wrought magnesium alloy;

[0010] It also includes surface-active elements selected from one or more combinations of Sb, Sr, Bi, and rare-earth elements La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y.

[0011] Preferably, the multi-principal element alloy is selected from AlCoCrFeNi 2.1 alloy, Al 20 Be 20 Fe 10 Si 15 Ti 35 alloy, Al 2 CrFeMnTi alloy, AlCrTiV alloy, Mg 20 (MnAlZnCu) 80 alloy, Al 63 Mg 27 Zn 4.5 Cu 4.5 Si 1 alloy, AlLi 0.5 MgZn 0.5 Cu 0.5 alloy, AlLiMgZnSn alloy, Al 20 Li 20 Mg 10 Sc 20 Ti 30 alloy, AlNbTiV alloy, AlFeMgTiZn alloy, Al 15 Li 35 Mg 48 Ca 1 Si 1 alloy, Al 40 Cu 15 Cr 15 Fe15 Si 15 alloy, Al 50 Ca 5 Cu 5 Ni 10 Si 20 Ti 10 alloy, DyGdLuTbTm alloy, DyGdLuTbY alloy, SmEuTbDyLu alloy, Er 20 Ho 20 Gd 20 Ni 20 Co 20 alloy, one or more combinations of GdTbHoErLa rare earth high entropy alloy, ErHoTb alloy, where x = 0 - 30%.

[0012] Preferably, the multi - principal - element alloy is selected from one or more combinations of AlCoCrFeNi system, AlLiMgZnSn system, AlMgZnCuSi system, Mg x (MnAlZnCu) 100-x system, AlCrTiV system, DyGdLuTbY system, AlCrFeMnTi system, SmEuTbDyLu system, AlNbTiV system, (CoCrNi) l00-x Al x system, ErHoTb system alloy, where x = 0 - 30%.

[0013] More specifically, the multi - principal - element alloy is selected from AlCoCrFeNi 2.1 , AlLiMgZnSn, Al 63 Mg 27 Zn 4.5 Cu 4.5 Si 1 , Mg 50 (MnAlZnCu) 50 , AlCrTiV, DyGdLuTbY, AlCrFeMnTi 0.25 , SmEuTbDyLu, AlNbTiV, (CoCrNi) 20 Al 80 system, ErHoTb alloy, one or more combinations thereof.

[0014] The multi - principal - element alloy selected in the present invention contains magnesium element, or has a high solid solubility in magnesium, or elements with a high diffusion rate in magnesium, which helps to improve the wettability and compatibility of the interface through the two - way diffusion between the multi - principal - element alloy and the magnesium alloy at the interface.

[0015] Preferably, the cast magnesium alloy is selected from one or more combinations of Mg-Al series, Mg-Zn series, and Mg-rare earth series cast magnesium alloys.

[0016] Preferably, the wrought magnesium alloy is selected from one or more combinations of Mg-Li series, Mg-Mn series, Mg-Al-Zn series, and Mg-Zn-Zr series wrought magnesium alloys.

[0017] More preferably, the magnesium alloy is selected from one or more combinations of AZ91 D, AM60, ZK60A, WE54, AE44, AZ31, ZK60, NZ30K, GWQ832K, and GZ112K magnesium alloys.

[0018] Preferably, the addition amount of the surface active element is 0.01% - 1%, preferably 0.05% - 0.5%. The role of the surface active element is to further improve the wettability of the multi-principal element alloy / magnesium alloy interface. However, it is prone to segregate at the multi-principal element alloy / magnesium alloy interface to form a surface active film, reducing the interfacial tension, significantly improving the contact relationship between the multi-principal element alloy / magnesium alloy melts, greatly enhancing the interfacial wettability between the multi-principal element alloy / magnesium alloy, and thus promoting the metallurgical bonding between the two metals. At the same time, the surface active element can also modify some second phases in the matrix, which helps to improve the microstructure. When the addition amount is greater than 0.01%, the surface active element significantly improves the wettability of the multi-principal element alloy / magnesium alloy interface. However, when the addition amount exceeds 1%, these elements will form brittle intermetallic compounds with magnesium, deteriorating the strength and toughness of the bimetallic material.

[0019] The second aspect of the present invention is to provide a preparation method for the above multi-principal element alloy / magnesium alloy bimetallic material, using the solid-liquid composite method, including the following steps:

[0020] (1) Pretreatment of the solid alloy. According to the solid-liquid composite requirements, select one of the two matrix alloys constituting the bimetallic material as the solid alloy, process the surface for composite on the solid alloy block material, polish the surface with sandpaper, and then carry out processes such as pickling, water washing, and drying to fully remove impurities and oxides on the composite surface. Subsequently, degrease the solid alloy, and finally coat the surface with an antioxidant and dry it to prepare for subsequent composite casting.

[0021] (2) Composite casting. Select the other one of the two matrix alloys that make up the dual-metal material as the liquid alloy. First, melt the required alloy according to the target composition to obtain an alloy melt, and after refining the melt, perform a standing treatment. At the same time, place the solid alloy preheated to the required temperature in a designated position in the mold cavity in advance. Before casting, add surface-active elements to the melt in the form of master alloys. After the master alloys are completely melted, slowly stir the melt to make the surface-active elements evenly distributed in the melt. Subsequently, adjust the melt to an appropriate temperature and then cast it into the mold, so that the composite surface of the melt and the pretreated solid alloy is in full contact. After the melt solidifies in an appropriate manner (atmospheric pressure solidification or high-pressure solidification), the metallurgical bonding of the two alloys is achieved, and finally a multi-principal element alloy / magnesium alloy dual-metal billet is obtained. Preferably, the pressure during the atmospheric pressure solidification or high-pressure solidification of the melt is controlled at 0-150 MPa, and the pressure holding time is 1-180 s.

[0022] (3) Heat treatment. First, perform high-temperature heat treatment on the dual-metal material ingot prepared in step (2) at a high temperature. The high-temperature heat treatment temperature is 5-50 °C below the solidus temperature of the matrix material, and the high-temperature heat treatment time is 2-100 h. Preferably, the high-temperature heat treatment temperature is 10-30 °C below the solidus temperature of the magnesium alloy matrix, and the high-temperature heat treatment time is 10-50 h. During the high-temperature heat treatment process, due to the concentration difference of different elements on both sides of the multi-principal element alloy / magnesium alloy interface, solutes tend to diffuse from the high-concentration region to the low-concentration region through the interface. The high-temperature heat treatment is to make full use of the characteristic that elements diffuse rapidly at high temperatures to form a solute supersaturated transition layer between the multi-principal element alloy and the magnesium alloy. The composition of this transition layer is still within the composition range of the multi-principal element alloy, so the formation of brittle intermetallic compounds at the interface is avoided, and thus the stress concentration at the multi-principal element alloy / magnesium alloy interface can be effectively alleviated. Subsequently, perform low-temperature heat treatment. The low-temperature heat treatment temperature is 100-250 °C, and the low-temperature heat treatment time is 2-200 h. Preferably, the low-temperature heat treatment temperature is 120-200 °C, and the low-temperature heat treatment time is 10-100 h. During the low-temperature heat treatment process, nano-scale precipitates will precipitate in the solute supersaturated transition layer at the multi-principal element alloy / magnesium alloy interface. These nano-precipitates can effectively hinder the movement of dislocations, thereby effectively strengthening the interface, and thus improving the overall performance and interface bonding ability of the dual-metal material.

[0023] The principle of the present invention can be summarized as follows: simultaneously improving the wettability and compatibility of the multi-principal element alloy / magnesium alloy interface and improving the interfacial microstructure of the multi-principal element alloy / magnesium alloy from three aspects: the alloy itself required for preparing the bimetallic material, surface active elements, and heat treatment. First, the multi-principal element alloy selected in the present invention contains magnesium elements or a large number of elements with high solid solubility or high diffusion ability in magnesium. The multi-principal element alloy / magnesium alloy naturally has interfacial bonding characteristics, and the wettability and compatibility of the interface are good. Further, the wettability of the multi-principal element alloy / magnesium alloy interface is further improved by surface active elements. Again, during the high-temperature heat treatment process, two-way element diffusion occurs between the multi-principal element alloy and the magnesium alloy through the interface. By reasonably controlling the temperature and time of the high-temperature heat treatment, a solute supersaturated transition zone is formed between the multi-principal element alloy and the magnesium alloy. Since the composition of this transition zone is still within the composition range of the multi-principal element alloy, the formation of brittle intermetallic compounds is avoided. Finally, during the low-temperature heat treatment process, nano-scale precipitates precipitate in the transition zone, thereby enhancing the ability of the multi-principal element alloy / magnesium alloy interface to resist deformation and damage. Through the above measures, the wettability and compatibility between the multi-principal element alloy / magnesium alloy interfaces are greatly improved, the stress concentration at the interface is relieved, and the interface is strengthened, thereby improving the overall strength, toughness, and interfacial bonding strength of the bimetallic material.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The constituent elements of the multi-principal element alloy selected in the present invention are common elements in magnesium alloys. These elements have high solid solubility or good diffusion ability in magnesium, fundamentally ensuring the wettability and compatibility of the multi-principal element alloy / magnesium alloy interface.

[0026] 2. Surface active elements are added during the preparation of the bimetallic material to further improve the wettability of the multi-principal element alloy / magnesium alloy interface.

[0027] 3. In the preparation method, a solute supersaturated transition zone is formed at the interface of the multi-principal element alloy / magnesium alloy through high-temperature heat treatment and low-temperature heat treatment in sequence, and nano-scale precipitates precipitate in the transition zone, relieving the stress concentration at the multi-principal element alloy / magnesium alloy interface and strengthening the interface at the same time.

[0028] 4. The multi-principal element alloy / magnesium alloy bimetallic material prepared by the present invention has good plasticity and interfacial bonding strength while ensuring high strength and hardness.

[0029] 5. The preparation method of the multi-principal element alloy / magnesium alloy bimetallic material provided by the present invention has strong operability and high efficiency. Specific Embodiments

[0030] The following combines examples to further describe the technical solutions of the present invention in detail.

[0031] Example 1: AlCoCrFeNi 2.1 Multi-principal element alloy / AZ91 D bimetallic material and its preparation process, without adding surface active elements and without heat treatment

[0032] The matrix materials used in this example are AlCoCrFeNi 2.1 Multi-principal element alloy and AZ91 D magnesium alloy. The specific components of the AZ91 D magnesium alloy are as follows by weight percentage: aluminum: 9.1%, zinc: 0.9%, manganese: 0.3%, and the rest is magnesium. The specific implementation steps are as follows:

[0033] (1) Pretreatment of multi-principal element alloy. AlCoCrFeNi 2.1 eutectic high-entropy alloy was prepared by ingot metallurgy method. A plane for composite was milled on the above high-entropy alloy ingot. After sanding the plane, pickling, water washing and drying and other processes were carried out to fully remove impurities and oxides on the composite surface. Subsequently, the multi-principal element alloy was degreased, and finally an antioxidant was coated on the composite surface and dried.

[0034] (2) Composite casting. The AZ91 D alloy ingot was melted using a crucible resistance furnace. After refining and degassing the alloy at 700 °C, the melt temperature was adjusted to 680 °C. At the same time, the pretreated high-entropy alloy was preheated at 400 °C for 2 h, and then fixed in the center of the metallic mold cavity. Then the melt was poured into the mold cavity so that the melt was in full contact with the composite surface of the high-entropy alloy. After the melt was completely solidified, the multi-principal element alloy / magnesium alloy bimetallic billet was obtained.

[0035] (3) The obtained AlCoCrFeNi 2.1 multi-principal element alloy / AZ91 D bimetallic ingot was air-cooled to room temperature. The interfacial bonding strength of the bimetallic material was tested by the tensile method, and the results showed that the interfacial bonding strength of the bimetallic material was 149.6 MPa.

[0036] Example 2: AlCoCrFeNi 2.1 Multi-principal element alloy / AZ91 D bimetallic material and its preparation process, adding surface active elements and without heat treatment

[0037] The matrix materials used in this example are AlCoCrFeNi 2.1 Multi-principal element alloy and AZ91 D magnesium alloy. The specific components of the AZ91 D magnesium alloy are as follows by weight percentage: aluminum: 9.1%, zinc: 0.9%, manganese: 0.3%, and the rest is magnesium. The surface active element is Sb element. The specific implementation steps are as follows:

[0038] (1) Pretreatment of multi-principal element alloy. AlCoCrFeNi2.1 A eutectic high-entropy alloy, a plane for compounding is milled on the above-mentioned high-entropy alloy ingot. After grinding the plane with sandpaper, pickling, water washing, drying and other processes are carried out to fully remove impurities and oxides on the compound surface. Subsequently, degreasing treatment is carried out on the multi-principal element alloy, and finally an antioxidant is coated on the compound surface and dried.

[0039] (2) Compound casting. Use a crucible resistance furnace to melt the AZ91D alloy ingot. After refining and degassing the alloy at 700 °C, adjust the melt temperature to 680 °C. At the same time, preheat the pretreated high-entropy alloy at 400 °C for 2 h, and then fix it in the center of the cavity of the metallic mold. Before casting, add Mg-20Sb master alloy according to the target content of Sb being 0.1%. After it is completely melted, slowly stir the melt to make Sb evenly distributed in the melt, and then pour the melt into the mold cavity so that the melt is in full contact with the compound surface of the high-entropy alloy. Wait for the melt to completely solidify to obtain a multi-principal element alloy / magnesium alloy bimetallic ingot.

[0040] (3) The obtained AlCoCrFeNi 2.1 The multi-principal element alloy / AZ91D bimetallic ingot is air-cooled to room temperature. The interfacial bonding strength of the bimetal is tested by the tensile method, and the results show that the interfacial bonding strength of the bimetallic material is 182.3 MPa.

[0041] Example 3: AlCoCrFeNi 2.1 Multi-principal element alloy / AZ91D bimetallic material and its preparation process, adding surface active elements and performing heat treatment

[0042] The base materials used in this example are AlCoCrFeNi 2.1 Multi-principal element alloy and AZ91D magnesium alloy. The specific components of the AZ91D magnesium alloy are as follows by weight percentage: aluminum: 9.1%, zinc: 0.9%, manganese: 0.3%, and the rest is magnesium. The surface active element is Sb element. The specific implementation steps are as follows:

[0043] (1) Pretreatment of multi-principal element alloy. Use ingot metallurgy method to prepare AlCoCrFeNi 2.1 A eutectic high-entropy alloy, a plane for compounding is milled on the above-mentioned high-entropy alloy ingot. After grinding the plane with sandpaper, pickling, water washing, drying and other processes are carried out to fully remove impurities and oxides on the compound surface. Subsequently, degreasing treatment is carried out on the multi-principal element alloy, and finally an antioxidant is coated on the compound surface and dried.

[0044] (2) Composite casting. The AZ91D alloy ingot was melted using a crucible resistance furnace. After refining and degassing the alloy at 700 °C, the melt temperature was adjusted to 680 °C. Meanwhile, the pretreated high-entropy alloy was preheated at 400 °C for 2 h and then fixed at the exact center of the metallic mold cavity. Before casting, the Mg-20Sb master alloy was added according to the proportion with the target content of Sb being 0.1%. After it was completely melted, the melt was slowly stirred to make Sb evenly distributed in the melt, and then the melt was cast into the mold cavity so that the composite surface of the melt and the high-entropy alloy was in full contact. After the melt was completely solidified, the multi-principal element alloy / magnesium alloy bimetallic billet was obtained.

[0045] (3) Heat treatment. After the obtained AlCoCrFeNi 2.1 multi-principal element alloy / AZ91D bimetallic ingot was held at 415 °C for 24 h, it was air-cooled to room temperature, then held at 200 °C for 16 h, and subsequently air-cooled to room temperature. The interfacial bonding strength of the bimetal was tested by the tensile method. The results showed that the interfacial bonding strength of the bimetallic material was 233.9 MPa.

[0046] Example 4: AlLiMgZnSn multi-principal element alloy / AM60B bimetallic material and its preparation process, adding surface active elements and performing heat treatment

[0047] The base materials used in this example were AlLiMgZnSn multi-principal element alloy and AM60B magnesium alloy respectively. The specific components of the AM60B magnesium alloy were as follows by weight percentage: aluminum: 5.7%, zinc: 0.1%, manganese: 0.3%, and the rest was magnesium. The surface active element was Sr element. The specific implementation steps were as follows:

[0048] (1) Pretreatment of multi-principal element alloy. The AlLiMgZnSn multi-principal element alloy was prepared by the ingot metallurgy method, and a plane for composite was milled on the above multi-principal element alloy ingot. After the plane was polished with sandpaper, pickling, water washing, drying and other processes were carried out to fully remove the impurities and oxides on the composite surface. Subsequently, the multi-principal element alloy was degreased, and finally an antioxidant was coated on the composite surface and dried.

[0049] (2) Composite casting. The AM60B alloy ingot was melted using a crucible resistance furnace. After refining and degassing the alloy at 700 °C, the melt temperature was adjusted to 680 °C. At the same time, the pretreated high-entropy alloy was preheated at 400 °C for 2 h and then fixed in the exact center of the metallic mold cavity. Before casting, the Mg-15Sr master alloy was added according to the target content of Sr being 0.01%. After it was completely melted, the melt was slowly stirred to make Sr evenly distributed in the melt. Subsequently, the melt temperature was adjusted to 680 °C, and the composite material ingot was formed using the squeeze casting method. The melt was cast into the metallic mold so that the composite surface of the melt and the high-entropy alloy was in full contact. Then, a pressure of 80 MPa was applied to the melt using a hydraulic press. After holding the pressure for 120 s, a multi-principal element alloy / magnesium alloy bimetallic billet was obtained.

[0050] (3) Heat treatment. The obtained AlLiMgZnSn multi-principal element alloy / AM60B bimetallic ingot was held at 415 °C for 15 h and then air-cooled to room temperature. Then, it was held at 200 °C for 2 h and subsequently air-cooled to room temperature. The interfacial bonding strength of the bimetal was tested using the tensile method. The results showed that the interfacial bonding strength of the bimetal material was 199.2 MPa.

[0051] Example 5: Al 63 Mg 27 Zn 4.5 Cu 4.5 Si 1 Multi-principal element alloy / ZK60A bimetal material and its preparation process, adding surface active elements and performing heat treatment

[0052] The matrix materials used in this example are Al 63 Mg 27 Zn 4.5 Cu 4.5 Si 1 The multi-principal element alloy and ZK60A magnesium alloy. The specific components of the ZK60A magnesium alloy are, by weight percentage: zirconium: 0.6%, zinc: 4.9%, and the rest is magnesium. The surface active element is Sr element. The specific implementation steps are as follows:

[0053] (1) Pretreatment of multi-principal element alloy. The Al 63 Mg 27 Zn 4.5 Cu 4.5 Si 1 Multi-principal element alloy was prepared by the ingot metallurgy method. A plane for composite was milled on the multi-principal element alloy ingot. After grinding the plane with sandpaper, pickling, water washing, and drying and other processes were carried out to fully remove the impurities and oxides on the composite surface. Subsequently, the multi-principal element alloy was degreased, and finally, an antioxidant was coated on the composite surface and then dried.

[0054] (2) Composite casting. The ZK60A alloy ingot was melted using a crucible resistance furnace. After refining and degassing the alloy at 700 °C, the melt temperature was adjusted to 680 °C. At the same time, the pretreated high-entropy alloy was preheated at 400 °C for 2 h and then fixed at the exact center of the metallic mold cavity. Before casting, the Mg-15Sr master alloy was added according to the proportion of the target Sr content of 0.1%. After it was completely melted, the melt was slowly stirred to make Sr evenly distributed in the melt. Subsequently, the melt temperature was adjusted to 690 °C, and the composite material ingot was formed using the squeeze casting method. The melt was cast into the metallic mold, making the composite surface of the melt and the high-entropy alloy in full contact. Then, a pressure of 50 MPa was applied to the melt using a hydraulic press. After holding the pressure for 180 s, the multi-principal element alloy / magnesium alloy bimetal billet was obtained.

[0055] (3) Heat treatment. After the obtained Al 63 Mg 27 Zn 4.5 Cu 4.5 Si 1 The multi-principal element alloy / ZK60A bimetal ingot was held at 500 °C for 4 h and then air-cooled to room temperature. Then it was held at 190 °C for 8 h and subsequently air-cooled to room temperature. The interfacial bonding strength of the bimetal was tested using the tensile method. The results showed that the interfacial bonding strength of the bimetal material was 285.6 MPa.

[0056] Example 6: Mg 50 (MnAlZnCu) 50 Multi-principal element alloy / WE54 bimetal material and its preparation process, adding surface active elements and performing heat treatment

[0057] The matrix materials used in this example were Mg 50 (MnAlZnCu) 50 multi-principal element alloy and WE54 magnesium alloy. The specific components of the WE54 magnesium alloy were as follows by weight percentage: yttrium: 5.4%, neodymium: 2.3%, gadolinium: 1.6%, zirconium: 0.5%, and the rest was magnesium. The surface active element was Bi element. The specific implementation steps were as follows:

[0058] (1) Pretreatment of multi-principal element alloy. The Mg 50 (MnAlZnCu) 50 multi-principal element alloy was prepared by the ingot metallurgy method. A plane for composite was milled on the multi-principal element alloy ingot. After grinding the plane with sandpaper, pickling, water washing, drying and other processes were carried out to fully remove the impurities and oxides on the composite surface. Subsequently, the multi-principal element alloy was degreased, and finally, an antioxidant was coated on the composite surface and dried.

[0059] (2) Composite casting. Use a crucible resistance furnace to melt the WE54 alloy ingot. After refining and degassing the alloy at 730 °C, adjust the melt temperature to 700 °C. At the same time, preheat the pretreated high-entropy alloy at 350 °C for 1.5 h, and then fix it in the center of the metallic mold cavity. Before casting, add the Mg-10Bi master alloy according to the target content of Bi being 0.15%. After it is completely melted, slowly stir the melt to make Bi evenly distributed in the melt, and then pour the melt into the mold cavity so that the composite surface of the melt and the high-entropy alloy is in full contact. Wait for the melt to completely solidify to obtain the multi-principal element alloy / magnesium alloy bimetallic billet.

[0060] (3) Heat treatment. After holding the obtained Mg 50 (MnAlZnCu) 50 multi-principal element alloy / WE54 bimetallic ingot at 525 °C for 6 h, air-cool it to room temperature, then hold it at 250 °C for 12 h, and then air-cool it to room temperature. Use the tensile method to test the interfacial bonding strength of the bimetal. The results show that the interfacial bonding strength of the bimetallic material is 332.1 MPa.

[0061] Example 7: AlCrTiV multi-principal element alloy / AE44 bimetallic material and its preparation process, adding surface active elements and performing heat treatment

[0062] The matrix materials used in this example are AlCrTiV multi-principal element alloy and AE44 magnesium alloy respectively. The specific components of the AE44 magnesium alloy are as follows by weight percentage: aluminum: 4.2%, lanthanum: 1.2%, cerium: 2.8%, manganese: 0.2%, calcium: 0.1%, and the rest is magnesium. The surface active element is Bi element. The specific implementation steps are as follows:

[0063] (1) Pretreatment of multi-principal element alloy. Prepare the AlCrTiV multi-principal element alloy by the ingot metallurgy method, and mill a plane for composite on the multi-principal element alloy ingot. After sanding the plane, perform pickling, water washing and drying and other processes to fully remove impurities and oxides on the composite surface. Then degrease the multi-principal element alloy, and finally coat an antioxidant on the composite surface and dry it.

[0064] (2) Composite casting. The AE44 alloy ingot was melted using a crucible resistance furnace. After refining and degassing the alloy at 730 °C, the melt temperature was adjusted to 700 °C. At the same time, the pretreated high-entropy alloy was preheated at 350 °C for 1.5 h and then fixed in the center of the metallic mold cavity. Before casting, the Mg-10Bi master alloy was added according to the proportion of the target content of Bi being 0.15%. After it was completely melted, the melt was slowly stirred to make Bi evenly distributed in the melt, and then the melt was cast into the mold cavity so that the composite surface of the melt and the high-entropy alloy was in full contact. After the melt was completely solidified, the multi-principal element alloy / magnesium alloy bimetal billet was obtained.

[0065] (3) Heat treatment. The obtained AlCrTiV multi-principal element alloy / AE44 bimetal ingot was held at 520 °C for 24 h and then air-cooled to room temperature. Then it was held at 170 °C for 36 h and subsequently air-cooled to room temperature. The interfacial bonding strength of the bimetal was tested by the tensile method. The results showed that the interfacial bonding strength of the bimetal material was 213.8 MPa.

[0066] Example 8: DyGdLuTbY multi-principal element alloy / AZ31 B bimetal material and its preparation process, adding surface active elements and performing heat treatment

[0067] The matrix materials used in this example were DyGdLuTbY multi-principal element alloy and AZ31 B magnesium alloy respectively. The specific components of the AZ31 B magnesium alloy were as follows by weight percentage: aluminum: 3.2%, zinc: 0.9%, manganese: 0.3%, and the rest was magnesium. The surface active element was Sr element. The specific implementation steps were as follows:

[0068] (1) Pretreatment of multi-principal element alloy. The DyGdLuTbY multi-principal element alloy was prepared by the ingot metallurgy method, and a plane for composite was milled on the multi-principal element alloy ingot. After the plane was polished with sandpaper, pickling, water washing and drying and other processes were carried out to fully remove the impurities and oxides on the composite surface. Subsequently, the multi-principal element alloy was degreased, and finally an antioxidant was coated on the composite surface and dried.

[0069] (2) Composite casting. Use a crucible resistance furnace to melt the AZ31B alloy ingot. After refining and degassing the alloy at 710 °C, adjust the melt temperature to 670 °C. At the same time, preheat the pretreated high-entropy alloy at 390 °C for 2.5 h, and then fix it in the center of the metallic mold cavity. Before casting, add Mg-10Sr master alloy according to the target content of Sr being 0.09%. After it is completely melted, slowly stir the melt to make Sr evenly distributed in the melt. Subsequently, adjust the melt temperature to 700 °C, and use the squeeze casting method to form the composite material ingot. Pour the melt into the metallic mold, making the composite surface of the melt and the high-entropy alloy in full contact. Then, apply a pressure of 70 MPa to the melt using a hydraulic press. After holding the pressure for 180 s, a multi-principal element alloy / magnesium alloy bimetallic ingot can be obtained.

[0070] (3) Heat treatment. Keep the obtained DyGdLuTbY multi-principal element alloy / AZ31B bimetallic ingot at 350 °C for 15 h, then air-cool it to room temperature, and then keep it at 120 °C for 200 h, and then air-cool it to room temperature. Use the tensile method to test the interfacial bonding strength of the bimetal. The results show that the interfacial bonding strength of the bimetallic material is 192.6 MPa.

[0071] Example 9: AlCrFeMnTi 0.25 Multi-principal element alloy / ZK60 bimetallic material and its preparation process, adding surface active elements and performing heat treatment

[0072] The base materials used in this example are AlCrFeMnTi 0.25 multi-principal element alloy and ZK60 magnesium alloy respectively. The specific components of the ZK60 magnesium alloy are as follows by weight percentage: zinc: 5.2%, zirconium: 0.5%, and the rest is magnesium. The surface active element is Y element. The specific implementation steps are as follows:

[0073] (1) Pretreatment of multi-principal element alloy. Use the ingot metallurgy method to prepare AlCrFeMnTi 0.25 multi-principal element alloy. Mill a plane for composite on the above multi-principal element alloy ingot. After sanding the plane, perform pickling, water washing, drying and other processes to fully remove impurities and oxides on the composite surface. Subsequently, degrease the multi-principal element alloy, and finally coat an antioxidant on the composite surface and dry it.

[0074] (2) Composite casting. Use a crucible resistance furnace to melt the ZK60 alloy ingot. After refining and degassing the alloy at 720 °C, adjust the melt temperature to 700 °C. At the same time, preheat the pretreated high-entropy alloy at 400 °C for 1 h, and then fix it in the center of the metallic mold cavity. Before casting, add the Mg-25Y master alloy according to the proportion of the target content of Y being 0.5%. After it is completely melted, slowly stir the melt to make Y evenly distributed in the melt, and then pour the melt into the mold cavity so that the composite surface of the melt and the high-entropy alloy is fully contacted. Wait for the melt to completely solidify to obtain the multi-principal element alloy / magnesium alloy bimetallic billet.

[0075] (3) Heat treatment. After holding the obtained AlCrFeMnTi 0.25 multi-principal element alloy / ZK60 bimetallic ingot at 500 °C for 4 h, air-cool it to room temperature, then hold it at 180 °C for 5 h, and then air-cool it to room temperature. Use the tensile method to test the interfacial bonding strength of the bimetal. The results show that the interfacial bonding strength of the bimetallic material is 265.2 MPa.

[0076] Example 10: SmEuTbDyLu multi-principal element alloy / NZ30K bimetallic material and its preparation process, adding surface active elements and performing heat treatment

[0077] The matrix materials used in this example are SmEuTbDyLu multi-principal element alloy and NZ30K magnesium alloy respectively. The specific components of the NZ30K magnesium alloy are as follows by weight percentage: neodymium: 3.1%, zinc: 0.2%, zirconium: 0.4%, and the rest is magnesium. The surface active element is Bi element. The specific implementation steps are as follows:

[0078] (1) Pretreatment of multi-principal element alloy. Use the ingot metallurgy method to prepare the SmEuTbDyLu multi-principal element alloy, and mill a plane for composite on the above-mentioned multi-principal element alloy ingot. After sanding the plane, perform pickling, water washing and drying and other processes to fully remove impurities and oxides on the composite surface. Then perform degreasing treatment on the multi-principal element alloy. Finally, coat an antioxidant on the composite surface and dry it.

[0079] (2) Composite casting. Use a crucible resistance furnace to melt the NZ30K alloy ingot. After refining and degassing the alloy at 720 °C, adjust the melt temperature to 700 °C. At the same time, preheat the pretreated high-entropy alloy at 400 °C for 2 h, and then fix it in the center of the metallic mold cavity. Before casting, add the Mg-10Bi master alloy according to the proportion of the target content of Bi being 0.15%. After it is completely melted, slowly stir the melt to make Bi evenly distributed in the melt, and then pour the melt into the mold cavity so that the composite surface of the melt and the high-entropy alloy is fully contacted. Wait for the melt to completely solidify to obtain the multi-principal element alloy / magnesium alloy bimetallic billet.

[0080] (3) Heat treatment. After holding the obtained SmEuTbDyLu multi-principal element alloy / NZ30K bimetal ingot at 510 °C for 7 h, it was air-cooled to room temperature, then held at 225 °C for 2 h, and subsequently air-cooled to room temperature. The interfacial bonding strength of the bimetal was tested by the tensile method, and the results showed that the interfacial bonding strength of the bimetal material was 231 MPa.

[0081] Example 11: AlNbTiV multi-principal element alloy / GWQ832K bimetal material and its preparation process, adding surface active elements and performing heat treatment

[0082] The matrix materials used in this example were AlNbTiV multi-principal element alloy and GWQ832K magnesium alloy respectively. The specific components of GWQ832K magnesium alloy were as follows by weight percentage: gadolinium: 7.9%, yttrium: 2.8%, zirconium: 0.4%, silver: 2%, and the rest was magnesium. The surface active element was Er element. The specific implementation steps were as follows:

[0083] (1) Pretreatment of multi-principal element alloy. The AlNbTiV multi-principal element alloy was prepared by ingot metallurgy method, and a plane for compounding was milled on the above multi-principal element alloy ingot. After grinding the plane with sandpaper, pickling, water washing and drying and other processes were carried out to fully remove impurities and oxides on the compound surface. Subsequently, the multi-principal element alloy was degreased, and finally an antioxidant was coated on the compound surface and dried.

[0084] (2) Composite casting. The GWQ832K alloy ingot was melted using a crucible resistance furnace. After refining and degassing the alloy at 720 °C, the melt temperature was adjusted to 700 °C. At the same time, the pretreated high-entropy alloy was preheated at 400 °C for 2 h, and then fixed in the center of the metallic mold cavity. Before casting, the Mg-20Er master alloy was added according to the proportion of the target content of Er being 0.15%. After it was completely melted, the melt was slowly stirred to make Er evenly distributed in the melt, and then the melt was cast into the mold cavity so that the melt was in full contact with the compound surface of the high-entropy alloy. After the melt was completely solidified, the multi-principal element alloy / magnesium alloy bimetal billet was obtained.

[0085] (3) Heat treatment. After holding the obtained AlNbTiV multi-principal element alloy / GWQ832K bimetal ingot at 510 °C for 7 h, it was air-cooled to room temperature, then held at 200 °C for 10 h, and subsequently air-cooled to room temperature. The interfacial bonding strength of the bimetal was tested by the tensile method, and the results showed that the interfacial bonding strength of the bimetal material was 307.1 MPa.

[0086] Example 12: (CoCrNi) 20 Al 80 multi-principal element alloy / GZ112K bimetal material and its preparation process, adding surface active elements and performing heat treatment

[0087] The matrix materials used in this embodiment are (CoCrNi) 20 Al 80 multi-principal element alloy and GZ112K magnesium alloy. The specific components of GZ112K magnesium alloy are as follows by weight percentage: gadolinium: 11.2%, zinc: 2.1%, zirconium: 0.4%, and the rest is magnesium. The surface active element is Sr element. The specific implementation steps are as follows:

[0088] (1) Pretreatment of multi-principal element alloy. The (CoCrNi) 20 Al 80 multi-principal element alloy is prepared by ingot metallurgy method. A plane for compounding is milled on the above-mentioned multi-principal element alloy ingot. After grinding the plane with sandpaper, pickling, water washing and drying and other processes are carried out to fully remove impurities and oxides on the compound surface. Subsequently, the multi-principal element alloy is degreased, and finally an antioxidant is coated on the compound surface and dried.

[0089] (2) Composite casting. The GZ112K alloy ingot is melted using a crucible resistance furnace. After refining and degassing the alloy at 730 °C, the melt temperature is adjusted to 700 °C. At the same time, the pre-treated high-entropy alloy is preheated at 400 °C for 1 h, and then fixed in the center of the metallic mold cavity. Before casting, the Mg-10Sr master alloy is added according to the proportion of the target content of Sr being 0.13%. After it is completely melted, the melt is slowly stirred to make Sr evenly distributed in the melt, and then the melt is cast into the mold cavity so that the melt is in full contact with the composite surface of the high-entropy alloy. After the melt is completely solidified, a multi-principal element alloy / magnesium alloy bimetallic billet is obtained.

[0090] (3) Heat treatment. The obtained (CoCrNi) 20 Al 80 multi-principal element alloy / GZ112K bimetallic ingot is held at 500 °C for 18 h and then air-cooled to room temperature, and then held at 185 °C for 54 h, and then air-cooled to room temperature. The interfacial bonding strength of the bimetal is tested by the tensile method. The results show that the interfacial bonding strength of the bimetallic material is 284.5 MPa.

[0091] Example 13: ErHoTb multi-principal element alloy / GZ112K bimetallic material and its preparation process, adding surface active elements and performing heat treatment

[0092] The matrix materials used in this embodiment are ErHoTb multi-principal element alloy and GZ112K magnesium alloy. The specific components of GZ112K magnesium alloy are as follows by weight percentage: gadolinium: 11.2%, zinc: 2.1%, zirconium: 0.4%, and the rest is magnesium. The surface active element is Bi element. The specific implementation steps are as follows:

[0093] (1) Pre-treatment of the multi-principal element alloy. The ErHoTb multi-principal element alloy was prepared by ingot metallurgy method, and a plane for compounding was milled on the above multi-principal element alloy ingot. After grinding the plane with sandpaper, pickling, water washing and drying processes were carried out to fully remove impurities and oxides on the compounding surface. Subsequently, the multi-principal element alloy was degreased, and finally an antioxidant was coated on the compounding surface and then dried.

[0094] (2) Compound casting. The GZ112K alloy ingot was melted using a crucible resistance furnace. After refining and degassing the alloy at 730 °C, the melt temperature was adjusted to 700 °C. At the same time, the pre-treated high-entropy alloy was preheated at 400 °C for 1 h and then fixed in the center of the metallic mold cavity. Before casting, the Mg-10Bi master alloy was added according to the target content of Bi being 0.13%. After it was completely melted, the melt was slowly stirred to make Bi evenly distributed in the melt, and then the melt was cast into the mold cavity so that the melt was in full contact with the compounding surface of the high-entropy alloy. After the melt was completely solidified, the multi-principal element alloy / magnesium alloy bimetal billet was obtained.

[0095] (3) Heat treatment. The obtained ErHoTb multi-principal element alloy / GZ112K bimetal ingot was held at 500 °C for 14 h and then air-cooled to room temperature, and then held at 185 °C for 46 h and subsequently air-cooled to room temperature. The interfacial bonding strength of the bimetal was tested by the tensile method, and the results showed that the interfacial bonding strength of the bimetal material was 263.8 MPa.

[0096] Example 14: Cylindrical AlCoCrFeNi 2.1 Multi-principal element alloy / AZ91 D bimetal material and its preparation process, adding surface active elements and performing heat treatment

[0097] The base materials used in this example are AlCoCrFeNi 2.1 Multi-principal element alloy and AZ91 D magnesium alloy. The specific components of AZ91 D magnesium alloy are as follows by weight percentage: aluminum: 9.1%, zinc: 0.9%, manganese: 0.3%, and the rest is magnesium. The surface active element is Sr element. The specific implementation steps are as follows:

[0098] (1) Pre-treatment of the solid alloy. The AZ91 D magnesium alloy was selected as the solid alloy, and a cylinder with a diameter of 50 mm and a length of 100 mm was machined. The surface of the above solid alloy was ground with sandpaper and pickling, water washing and drying processes were carried out to fully remove impurities and oxides on the compounding surface. Subsequently, the solid alloy was degreased, and finally an antioxidant was coated on the compounding surface and then dried.

[0099] (2) Compound casting. Select AlCoCrFeNi 2.1As a liquid alloy, the eutectic high-entropy alloy is melted in a crucible resistance furnace with AlCoCrFeNi 2.1 alloy ingots. At the same time, the pre-treated AZ91 D magnesium alloy is preheated at 200 °C for 2 h, and then fixed in the exact center of the metallic mold cavity. The mold shape is adjusted so that the remaining thickness of the mold cavity is 2 mm. Before casting, an Al-10Sr master alloy is added to the melt according to the target content of Sr being 0.15%. After it is completely melted, the melt is slowly stirred to make Sr evenly distributed in the melt. Then the melt is cast into the mold cavity so that the composite surface of the melt and the high-entropy alloy is fully contacted. After the melt is completely solidified, a multi-principal element alloy / magnesium alloy bimetallic billet is obtained, where the multi-principal element alloy layer is distributed on the surface of the billet with a thickness of 2 mm.

[0100] (3) Heat treatment. After the obtained AlCoCrFeNi 2.1 multi-principal element alloy / AZ91 D magnesium alloy bimetallic ingot is held at 415 °C for 24 h, it is air-cooled to room temperature, then held at 200 °C for 16 h, and then air-cooled to room temperature. The interfacial bonding strength of the bimetal is tested by the tensile method. The results show that the interfacial bonding strength of the bimetallic material is 236.8 MPa. In addition, this bimetallic material has excellent wear resistance.

[0101] The mechanical properties of the bimetallic materials obtained in the above Examples 1-14 are shown in Table 1:

[0102] Table 1: Mechanical properties of the bimetallic materials involved in the examples

[0103]

[0104]

[0105] It can be seen from Examples 1-3 and Table 1 that adding surface active elements can improve the interfacial bonding strength of the bimetallic material. After subsequent high-temperature and low-temperature heat treatments, the interfacial bonding strength of the bimetallic material is further greatly improved. It can be seen from Examples 3-12 and Table 1 that the method described in the present invention has good applicability to different types of multi-principal element alloy and magnesium alloy matrix materials.

[0106] The above description of the embodiments is for those of ordinary skill in the art to understand and use the present invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art according to the principles of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A multi-principal element alloy / magnesium alloy bimetallic material, characterized in that, it includes a multi-principal element alloy and a magnesium alloy; The multi-principal element alloy is selected from one or more combinations of AlCoCrFeNi series, AlBeFeSiTi series, AlCrFeMnTi series, AlCrTiV series, Mg x (MnAlZnCu) 100-x series, AlMgZnCuSi series, AlLiMgZnCu series, AlLiMgZnSn series, AlLiMgScTi series, AlNbTiV series, AlFeMgTiZn series, AlLiMgCaSi series, AlCuCrFeSi series, AlCaCuNiSiTi series high-entropy alloys, DyGdLuTbTm series, DyGdLuTbY series, SmEuTbDyLu series, ErHoGdNiCo series, GdTbHoEr(La, Y) series rare-earth high-entropy alloys, and (CoCrNi) l00-x Al x series, ErHoTb series alloys, where x = 0 - 30%; the magnesium alloy includes a cast magnesium alloy and a wrought magnesium alloy; it further includes surface active elements selected from one or a combination of two or more of Sb, Sr, Bi and rare earth elements La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y; The multi-principal element alloy / magnesium alloy bimetallic material is prepared by a solid-liquid composite method, and the preparation method includes the following steps: (1) Solid alloy pretreatment: According to the solid-liquid composite requirements, select one of the two matrix alloys that make up the bimetallic material as the solid alloy. Process the surface for composite on the solid alloy block material, and polish the surface with sandpaper. Subsequently, use pickling, water washing and drying processes to fully remove impurities and oxides on the composite surface, degrease the solid alloy, and finally coat the composite surface with an antioxidant and then dry it; (2) Composite casting: Select the other of the two matrix alloys that make up the bimetallic material as the liquid alloy. First, melt the required alloy according to the target composition to obtain an alloy melt, refine the melt, and let it stand; at the same time, place the solid alloy preheated to the required temperature in the mold cavity in advance. Before casting, add the surface active element to the melt in the form of master alloy. After the master alloy is completely melted, slowly stir the melt to make the surface active element evenly distributed in the melt. Then adjust the temperature of the melt and cast it into the mold, so that the melt is in full contact with the pre-treated composite surface of the solid alloy. The melt is solidified at normal pressure or high pressure to achieve the metallurgical bonding of the two alloys, and a multi-principal element alloy / magnesium alloy bimetallic casting blank is obtained; (3) Heat treatment: Perform high-temperature heat treatment on the multi-principal element alloy / magnesium alloy bimetallic casting blank prepared in step (2) at a high temperature. The high-temperature heat treatment temperature is 5-50 °C below the solidus temperature of the matrix material, and the high-temperature heat treatment time is 2-100 h to form a solute supersaturated transition layer between the multi-principal element alloy and the magnesium alloy; subsequently, perform low-temperature heat treatment. The temperature of the low-temperature heat treatment is 100-250 °C, and the time of the low-temperature heat treatment is 2-100 h, thus obtaining the product.

2. The multi-principal element alloy / magnesium alloy bimetallic material according to claim 1, characterized in that, The multi-principal element alloy is selected from AlCoCrFeNi 2.1 alloy, Al 20 Be 20 Fe 10 Si 15 Ti 35 alloy, Al 2 CrFeMnTi alloy, AlCrTiV alloy, Mg 20 (MnAlZnCu) 80 alloy, Al 63 Mg 27 Zn 4.5 Cu 4.5 Si 1 alloy, AlLi 0.5 MgZn 0.5 Cu 0.5 alloy, AlLiMgZnSn alloy, Al 20 Li 20 Mg 10 Sc 20 Ti 30 alloy, AlNbTiV alloy, AlFeMgTiZn alloy, Al 15 Li 35 Mg 48 Ca 1 Si 1 alloy, Al 40 Cu 15 Cr 15 Fe 15 Si 15 alloy, Al 50 Ca 5 Cu 5 Ni 10 Si 20 Ti 10 alloy, DyGdLuTbTm alloy, DyGdLuTbY alloy, SmEuTbDyLu alloy, Er 20 Ho 20 Gd 20 Ni 20 Co 20 alloy, GdTbHoErLa rare earth high entropy alloy, ErHoTb alloy, or a combination of two or more thereof, where x = 0 - 30%.

3. The multi-principal element alloy / magnesium alloy bimetallic material according to claim 1, characterized in that, The multi-principal element alloy is selected from one or a combination of two or more of the AlCoCrFeNi system, AlLiMgZnSn system, AlMgZnCuSi system, Mg x (MnAlZnCu) 100-x system, AlCrTiV system, DyGdLuTbY system, AlCrFeMnTi system, SmEuTbDyLu system, AlNbTiV system, (CoCrNi) l00-x Al x system, ErHoTb system alloys, where x = 0 - 30%.

4. The multi-principal element alloy / magnesium alloy bimetallic material according to claim 3, characterized in that, The multi-principal element alloy is selected from AlCoCrFeNi 2.1 , AlLiMgZnSn, Al 63 Mg 27 Zn 4.5 Cu 4.5 Si 1 , Mg 50 (MnAlZnCu) 50 , AlCrTiV, DyGdLuTbY, AlCrFeMnTi 0.25 , SmEuTbDyLu, AlNbTiV, (CoCrNi) 20 Al 80 , or a combination of two or more of ErHoTb alloys.

5. The multi-principal element alloy / magnesium alloy bimetallic material according to claim 1, characterized in that, the cast magnesium alloy is selected from one or a combination of two or more of Mg-Al series, Mg-Zn series, Mg-rare earth series cast magnesium alloys; and / or the wrought magnesium alloy is selected from one or a combination of two or more of Mg-Li series, Mg-Mn series, Mg-Al-Zn series, Mg-Zn-Zr series wrought magnesium alloys.

6. The multi-principal element alloy / magnesium alloy bimetallic material according to claim 5, characterized in that, The magnesium alloy is selected from one or more combinations of AZ91 D, AM60, ZK60A, WE54, AE44, AZ31, ZK60, NZ30K, GWQ832K, and GZ112K magnesium alloys.

7. The multi-principal element alloy / magnesium alloy bimetallic material according to claim 1, characterized in that in step (2), the pressure during atmospheric pressure solidification or high-pressure solidification of the melt is controlled at 0-150 MPa, and the pressure holding time is 1-180 s.

8. The multi-principal element alloy / magnesium alloy bimetallic material according to claim 1, characterized in that in step (3), the high-temperature heat treatment temperature is 10-30 °C below the solidus temperature of the magnesium alloy matrix, and the high-temperature heat treatment time is 10-50 h; the low-temperature heat treatment temperature is 120-200 °C, and the low-temperature heat treatment time is 10-100 h.

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