Ultrahigh-strength rare earth magnesium alloy deformed material and preparation method thereof

Abstract

The invention provides an ultrahigh-strength rare earth magnesium alloy deformed material and a preparation method thereof. The ultrahigh-strength rare earth magnesium alloy deformed material is composed of the following components in percentage by mass: 10%-11% of Gd, 2.5%-4.0% of Y, 0.35%-0.5% of Zr, 0.2%-0.6% of Ce and the balance of Mg. According to the ultrahigh-strength rare earth magnesium alloy deformed material provided by the invention, microelements (such as Ca, Ce, La and Ag which are controlled within 1mass%) are added into the magnesium alloy, so that the microstructure and texture of the alloy can be regulated and controlled, the precipitation of a second phase is promoted, the mechanical property of the magnesium alloy is improved, and the material cost and weight are reduced; and the method has important significance on cyclic utilization and sustainable development of magnesium resources.

Description

Technical Field

[0001] The present invention relates to the technical field of magnesium alloy materials, and in particular to an ultra-high strength rare earth magnesium alloy deformed material and a preparation method thereof. Background Art

[0002] With the progress of modern industry, magnesium alloys have shown important application value and broad development prospects in the fields of manned spaceflight, weapons and equipment, automobile manufacturing and 3C electronic products. Despite the huge potential of magnesium alloys, their actual engineering applications and output are still far less than those of steel and aluminum. The main reason is that the hexagonal close-packed (hcp) crystal structure provides limited slip systems, which does not meet the formability requirements of the Von-Mises criterion, resulting in poor plasticity and formability at room temperature, thus limiting wider engineering applications. Summary of the invention

[0003] In view of the defects in the prior art, the purpose of the present invention is to provide an ultra-high strength rare earth magnesium alloy deformed material and a preparation method thereof.

[0004] The first aspect of the present invention provides an ultra-high strength rare earth magnesium alloy deformed material, which is composed of the following components in percentage by mass: Gd: 10%-11%, Y: 2.5%-4.0%, Zr: 0.35%-0.5%, Ce: 0.2%-0.6%, and the balance is Mg.

[0005] In one embodiment of the present invention, the yield strength of the ultra-high strength rare earth magnesium alloy is 443MPa-451MPa, the tensile strength is 489MPa-513MPa, and the elongation is 6.1%-6.7%.

[0006] The second aspect of the present invention provides a method for preparing the ultra-high strength rare earth magnesium alloy deformed material, comprising the following steps:

[0007] S1, melting the raw material of the ultra-high strength rare earth magnesium alloy deformed material and then casting it to obtain a magnesium alloy ingot;

[0008] S2, casting the magnesium alloy into a resistance furnace for homogenization treatment, and then peeling;

[0009] S3. After homogenization is completed, isothermal extrusion processing is performed;

[0010] S4. After the isothermal extrusion process is completed, an aging treatment is performed to obtain the ultra-high strength magnesium alloy deformed material.

[0011] In one embodiment of the present invention, the raw materials of the ultra-high strength rare earth magnesium alloy are Mg ingot, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy, and Mg-30Ce.

[0012] In one embodiment of the present invention, step S1 is specifically as follows: melt the raw material Mg ingot, heat it to 710°C, add Mg-30Gd intermediate alloy and Mg-30Y intermediate alloy in sequence, keep it warm for 10 minutes, set the furnace temperature to 740°C, continue to keep it warm for 15 minutes, add Mg-30Zr intermediate alloy and Mg-30Ce, continue to keep it warm for 15 minutes for refining and stirring, and the smelting is completed to obtain alloy liquid; cast the magnesium alloy ingot with the alloy liquid.

[0013] In one embodiment of the present invention, step S2 is specifically as follows: the magnesium alloy ingot is kept at 500°C-520°C for 18h-22h; then air-cooled, peeled, and homogenized.

[0014] In one embodiment of the present invention, it is characterized in that when performing isothermal extrusion treatment, the magnesium alloy ingot after homogenization treatment is preheated to 410°C-425°C, and the mold is preheated to 390°C to ensure that the temperature is maintained at 410°C during the extrusion process.

[0015] In one embodiment of the present invention, it is characterized in that during the extrusion process, the extrusion ratio is 11-14.

[0016] In one embodiment of the present invention, after the extrusion treatment, the extruded rod is placed in a muffle furnace at 200° C. for 48 hours and then taken out for air cooling.

[0017] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0018] In the ultra-high strength rare earth magnesium alloy deformed material provided by the present invention, by adding trace elements (such as Ca, Ce, La and Ag, controlled within 1 mass%) to the magnesium alloy, the microstructure and texture of the alloy can be regulated, and the precipitation of the second phase can be promoted, which not only improves the mechanical properties of the magnesium alloy, but also reduces the material cost and weight, which is of great significance for the recycling and sustainable development of magnesium resources. Specifically, (1) Ce is a light rare earth element belonging to the lanthanide series, and has a very low solid solubility in pure magnesium. The maximum solid solubility is 0.74 mass% at 592°C, and it drops sharply with decreasing temperature. When the temperature drops to 200°C, the solid solubility of Ce is only 0.04 mass%. The atomic radius of Ce is 0.27nm, which is larger than the atomic radius of Mg of 0.172nm. The atomic size mismatch is large, the diffusion rate is fast, and it is easy to induce aggregation at the grain boundary. In addition, the addition of Ce can effectively activate the non-basal slip of magnesium alloys, especially the conical surface.<c+a> Slip, which is of great significance to improving the formability of magnesium alloys; (2) Ce is an ideal alloying element for refining magnesium alloy grains and weakening texture. When magnesium alloys are subjected to plastic deformation, Ce atoms interact strongly with dislocations at grain boundaries, delaying grain boundary mobility through the solute drag effect, and weakening the strong basal texture of magnesium alloys; (3) Ce is a relatively inexpensive light rare earth element with abundant reserves in my country. Compared with traditional magnesium alloys with high rare earth content, the present invention has the advantage of significantly reducing the cost and weight of magnesium alloys through Ce microalloying. DETAILED DESCRIPTION

[0019] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0020] Example 1

[0021] The present embodiment provides an ultra-high strength rare earth magnesium alloy deformed material, which is composed of the following components in percentage by mass: Gd: 10%, Y: 2.5%, Zr: 0.35%, Ce: 0.2%, and the balance is Mg.

[0022] The preparation method of the ultra-high strength rare earth magnesium alloy deformed material is as follows:

[0023] The total weight of each batch is 5kg. When mixing the materials, the burn-out ratio is adjusted according to the type and content range of the alloy elements.

[0024] The raw materials used are: pure Mg, Mg-30Gd, Mg-30Y, Mg-30Zr, and Mg-30Ce. Bake the ingredients and mold before smelting. Set the initial furnace temperature to 710°C, put pure Mg into the furnace and heat it up with the furnace, and pass protective gas (N2+SF6). When the furnace temperature rises to 710°C, pure Mg begins to melt after about 10min-15min, and the furnace temperature drops to 670°C. When the melt temperature rises to 750°C again, add Mg-30Gd and Mg-30Y. After keeping warm for 10min, set the furnace temperature to 750°C, continue to keep warm for 15min, then add Mg-30Zr and Mg-30Ce alloying elements, and continue to keep warm for 15min. Then, refining and stirring are carried out. The refining agent is 1.2% of the total weight of the ingredients, i.e. 0.06 kg. Stirring: left and right 100 times, up and down 60 times, left and right 100 times, up and down 60 times, left and right 100 times. Take a small ingot from the melt to measure the direct reading spectrum. If the composition meets the standard, the melt is left to stand for 45 minutes before casting. If the composition does not meet the standard, the material is supplemented until the final direct reading composition is close to the nominal composition.

[0025] The magnesium alloy ingot was placed in a muffle furnace at 500°C for 20 hours, followed by air cooling, peeling, and homogenization.

[0026] During isothermal extrusion, the magnesium alloy ingot after homogenization treatment is preheated to 420°C, and the mold is preheated to 390°C to ensure that the temperature is maintained at 410°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 13.

[0027] After extrusion treatment, the extruded rods were placed in a muffle furnace at 200°C for 48 h and then taken out for air cooling.

[0028] Example 2

[0029] The present embodiment provides an ultra-high strength rare earth magnesium alloy deformed material, which is composed of the following components in percentage by mass: Gd: 11%, Y: 4.0%, Zr: 0.5%, Ce: 0.6%, and the balance is Mg.

[0030] The preparation method of the ultra-high strength rare earth magnesium alloy deformed material is as follows:

[0031] The total weight of each batch is 5kg. When batching, the burnout ratio is adjusted according to the type and content range of the alloying elements. The raw materials used are: pure Mg, Mg-30Gd, Mg-30Y, Mg-30Zr, and Mg-30Ce. Bake the batch and mold before smelting. Set the initial furnace temperature to 710℃, put pure Mg into the furnace and heat it up with the furnace, and pass the protective gas (N2+SF6). When the furnace temperature rises to 710℃, pure Mg begins to melt after about 10min-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Gd and Mg-30Y. After keeping warm for 10min, set the furnace temperature to 750℃, continue to keep warm for 15min, then put Mg-30Zr and Mg-30Ce alloying elements, and continue to keep warm for 15min. Then, refining and stirring are carried out. The refining agent is 1.2% of the total weight of the ingredients, i.e. 0.06 kg. Stirring: left and right 100 times, up and down 60 times, left and right 100 times, up and down 60 times, left and right 100 times. Take a small ingot from the melt to measure the direct reading spectrum. If the composition meets the standard, the melt is left to stand for 45 minutes before casting. If the composition does not meet the standard, the material is supplemented until the final direct reading composition is close to the nominal composition.

[0032] The magnesium alloy ingot was placed in a muffle furnace at 500°C for 20 hours, followed by air cooling, peeling, and homogenization.

[0033] During isothermal extrusion, the magnesium alloy ingot after homogenization treatment is preheated to 420°C, and the mold is preheated to 390°C to ensure that the temperature is maintained at 410°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 13.

[0034] After extrusion treatment, the extruded rods were placed in a muffle furnace at 200°C for 48 h and then taken out for air cooling.

[0035] Example 3

[0036] The present embodiment provides an ultra-high strength rare earth magnesium alloy deformed material, which is composed of the following components in percentage by mass: Gd: 10.5%, Y: 3%, Zr: 0.4%, Ce: 0.4%, and the balance is Mg.

[0037] The preparation method of the ultra-high strength rare earth magnesium alloy deformed material is as follows:

[0038] The total weight of each batch is 5kg. When mixing the materials, the burn-out ratio is adjusted according to the type and content range of the alloy elements.

[0039] The raw materials used are: pure Mg, Mg-30Gd, Mg-30Y, Mg-30Zr, and Mg-30Ce. Bake the ingredients and mold before smelting. Set the initial furnace temperature to 710°C, put pure Mg into the furnace and heat it up with the furnace, and pass protective gas (N2+SF6). When the furnace temperature rises to 710°C, pure Mg begins to melt after about 10min-15min, and the furnace temperature drops to 670°C. When the melt temperature rises to 750°C again, add Mg-30Gd and Mg-30Y. After keeping warm for 10min, set the furnace temperature to 750°C, continue to keep warm for 15min, then add Mg-30Zr and Mg-30Ce alloying elements, and continue to keep warm for 15min. Then, refining and stirring are carried out. The refining agent is 1.2% of the total weight of the ingredients, i.e. 0.06 kg. Stirring: left and right 100 times, up and down 60 times, left and right 100 times, up and down 60 times, left and right 100 times. Take a small ingot from the melt to measure the direct reading spectrum. If the composition meets the standard, the melt is left to stand for 45 minutes before casting. If the composition does not meet the standard, the material is supplemented until the final direct reading composition is close to the nominal composition.

[0040] The magnesium alloy ingot was placed in a muffle furnace at 500°C for 20 hours, followed by air cooling, peeling, and homogenization.

[0041] During isothermal extrusion, the magnesium alloy ingot after homogenization treatment is preheated to 420°C, and the mold is preheated to 390°C to ensure that the temperature is maintained at 410°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 13.

[0042] After extrusion treatment, the extruded rods were placed in a muffle furnace at 200°C for 48 h and then taken out for air cooling.

[0043] Comparative Example 1

[0044] This comparative example provides a rare earth magnesium alloy deformation material, which is composed of the following components in percentage by mass: Gd: 10%, Y: 2.5%, Zr: 0.5%, Ce: 0.1%, and the balance is Mg.

[0045] The preparation method of the rare earth magnesium alloy deformed material in this comparative example is as follows:

[0046] The total weight of each batch is 5kg. When mixing the materials, the burn-out ratio is adjusted according to the type and content range of the alloy elements.

[0047] The raw materials used are: pure Mg, Mg-30Gd, Mg-30Y, Mg-30Zr, and Mg-30Ce. Bake the ingredients and mold before smelting. Set the initial furnace temperature to 710°C, put pure Mg into the furnace and heat it up with the furnace, and pass protective gas (N2+SF6). When the furnace temperature rises to 710°C, pure Mg begins to melt after about 10min-15min, and the furnace temperature drops to 670°C. When the melt temperature rises to 750°C again, add Mg-30Gd and Mg-30Y. After keeping warm for 10min, set the furnace temperature to 750°C, continue to keep warm for 15min, then add Mg-30Zr and Mg-30Ce alloying elements, and continue to keep warm for 15min. Then, refining and stirring are carried out. The refining agent is 1.2% of the total weight of the ingredients, i.e. 0.06 kg. Stirring: left and right 100 times, up and down 60 times, left and right 100 times, up and down 60 times, left and right 100 times. Take a small ingot from the melt to measure the direct reading spectrum. If the composition meets the standard, the melt is left to stand for 45 minutes before casting. If the composition does not meet the standard, the material is supplemented until the final direct reading composition is close to the nominal composition.

[0048] The magnesium alloy ingot was placed in a muffle furnace at 500°C for 20 hours, followed by air cooling, peeling, and homogenization.

[0049] During isothermal extrusion, the magnesium alloy ingot after homogenization treatment is preheated to 420°C, and the mold is preheated to 390°C to ensure that the temperature is maintained at 410°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 13.

[0050] After extrusion treatment, the extruded rods were placed in a muffle furnace at 200°C for 48 h and then taken out for air cooling.

[0051] Comparative Example 2

[0052] This comparative example provides a rare earth magnesium alloy deformation material, which is composed of the following components in percentage by mass: Gd: 10%, Y: 2.5%, Zr: 0.5%, and the balance is Mg.

[0053] The preparation method of the rare earth magnesium alloy deformed material in this comparative example is as follows:

[0054] The total weight of each batch is 5kg. When mixing the materials, the burn-out ratio is adjusted according to the type and content range of the alloy elements.

[0055] The raw materials used are: pure Mg, Mg-30Gd, Mg-30Y, and Mg-30Zr. Bake the ingredients and molds before smelting. Set the initial furnace temperature to 710°C, put pure Mg into the furnace and heat it up with the furnace, and pass the protective gas (N2+SF6). When the furnace temperature rises to 710°C, pure Mg begins to melt after about 10min-15min, and the furnace temperature drops to 670°C. When the melt temperature rises to 750°C again, add Mg-30Gd and Mg-30Y. After keeping warm for 10min, set the furnace temperature to 750°C, continue to keep warm for 15min, then put Mg-30Zr alloy, and continue to keep warm for 15min. Then refine and stir, and the refining agent takes 1.2% of the total ingredient weight, that is, 0.06kg; stir: left and right 100 times, up and down 60 times, left and right 100 times, up and down 60 times, left and right 100 times. Take a small ingot from the melt and measure the direct reading spectrum. If the composition meets the standard, let the melt stand for 45 minutes before casting. If the composition does not meet the standard, add material until the final direct reading composition is close to the nominal composition.

[0056] The magnesium alloy ingot was placed in a muffle furnace at 500°C for 20 hours, followed by air cooling, peeling, and homogenization.

[0057] During isothermal extrusion, the magnesium alloy ingot after homogenization treatment is preheated to 420°C, and the mold is preheated to 390°C to ensure that the temperature is maintained at 410°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 13.

[0058] After extrusion treatment, the extruded rods were placed in a muffle furnace at 200°C for 48 h and then taken out for air cooling.

[0059] Experimental Example 1

[0060] In this experimental example, the properties of the deformed rare earth magnesium alloys obtained in Examples 1-3 and Comparative Examples 1-2 were tested, and the test results are shown in Table 1. Among them, no Ce element was added in Comparative Example 1, and an excessive amount of Ce element was added in Comparative Example 2, and the results are shown in Table 1. From the performance comparison in Table 1, the trace addition of Ce in the present invention has a significant effect on the performance improvement of the Mg-Gd-Y-Zr alloy.

[0061] Table 1 Room temperature mechanical properties of examples and comparative examples

[0062]

[0063] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. An ultra-high strength rare earth magnesium alloy deformed material, characterized in that: The alloy is composed of the following components in percentage by mass: Gd: 10%-11%, Y: 2.5%-4.0%, Zr: 0.35%-0.5%, Ce: 0.2%-0.6%, and the balance is Mg.

2. The ultra-high strength rare earth magnesium alloy deformed material according to claim 1, characterized in that: The ultra-high strength rare earth magnesium alloy has a yield strength of 443 MPa-451 MPa, a tensile strength of 489 MPa-513 MPa, and an elongation of 6.1%-6.7%.

3. The method for preparing the ultra-high strength rare earth magnesium alloy deformed material according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1, melting the raw material of the ultra-high strength rare earth magnesium alloy deformed material and then casting it to obtain a magnesium alloy ingot; S2, casting the magnesium alloy into a resistance furnace for homogenization treatment, and then peeling; S3. After homogenization is completed, isothermal extrusion processing is performed; S4. After the isothermal extrusion process is completed, an aging treatment is performed to obtain the ultra-high strength magnesium alloy deformed material.

4. The method for preparing the ultra-high strength rare earth magnesium alloy deformed material according to claim 3, characterized in that: The raw materials of the ultra-high strength rare earth magnesium alloy are Mg ingot, Mg-30Gd master alloy, Mg-30Y master alloy, Mg-30Zr master alloy and Mg-30Ce.

5. The method for preparing the ultra-high strength rare earth magnesium alloy deformed material according to claim 3, characterized in that: Step S1 is as follows: melt the raw material Mg ingot, heat it to 710°C, add Mg-30Gd master alloy and Mg-30Y master alloy in sequence, keep it warm for 10 minutes, set the furnace temperature to 740°C, continue to keep it warm for 15 minutes, add Mg-30Zr master alloy and Mg-30Ce, continue to keep it warm for 15 minutes for refining and stirring, and the smelting is completed to obtain alloy liquid; cast the magnesium alloy ingot with the alloy liquid.

6. The method for preparing the ultra-high strength rare earth magnesium alloy deformed material according to claim 5, characterized in that: Step S2 is specifically as follows: the magnesium alloy ingot is kept at 500°C-520°C for 18h-22h; then air-cooled, peeled, and homogenized.

7. The method for preparing a deformed ultra-high strength rare earth magnesium alloy according to claim 6, characterized in that: During isothermal extrusion, the magnesium alloy ingot after homogenization is preheated to 410°C-425°C, and the mold is preheated to 390°C to ensure that the temperature is maintained at 410°C during the extrusion process.

8. The method for preparing the ultra-high strength rare earth magnesium alloy deformed material according to claim 7, characterized in that: It is characterized in that When extrusion processing is performed, the extrusion ratio is 11-14.

9. The method for preparing an ultra-high strength rare earth magnesium alloy deformed material according to claim 8, characterized in that: After extrusion treatment, the extruded rod was placed in a muffle furnace at 200°C for 48 hours and then taken out for air cooling.

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