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

Abstract

The invention belongs to the technical field of rare earth magnesium alloy materials, and discloses an ultrahigh-strength rare earth magnesium alloy deformed material which is prepared from the following raw materials in percentage by mass: 9.6%-10.4% of Gd, 3.2%-4.3% of Y, 1.4%-2.1% of Zn, 0.37%-0.51% of Zr, 0.4%-0.7% of Nd, 0.8%-1.2% of Er and the balance of Mg. The invention further discloses a preparation method of the magnesium alloy deformed material. The preparation method comprises the steps of smelting and casting, homogenizing treatment, variable-speed isothermal extrusion treatment, aging treatment and the like. By adding Nd and Er elements and adjusting the ratio of all metal elements in the alloy, the magnesium alloy shows excellent comprehensive mechanical properties, the yield strength of the magnesium alloy ranges from 384 MPa to 388 MPa, the tensile strength ranges from 468 MPa to 474 MPa, and the ductility ranges from 8.5% to 8.9%.

Description

Technical Field

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

[0002] Under the sustainable development concept of "energy saving, environmental protection, and green", magnesium alloys are praised as "green engineering materials of the 21st century" due to their lightweight, biodegradable and recyclable characteristics, and have received extensive attention. In addition, magnesium alloys also have excellent thermal conductivity, high specific strength and specific stiffness, good mechanical properties and recyclability, etc., and have important applications and broad development prospects in the fields of national defense, military products, automobile production, electronic components, etc.

[0003] Among the existing ultra-high strength rare earth magnesium alloys, for example, Chinese patent publication number CN115478199 discloses a high-strength and toughness magnesium alloy deformed material and its preparation method, the element composition of the high-strength and toughness magnesium alloy deformed material includes: Zn: 6.2% to 6.5%, Ce: 0.2% to 0.5%, Ca: 0.3% to 0.8%, Zr: 0.3% to 0.5%, and the balance is Mg. After homogenization treatment and differential temperature extrusion deformation, the rare earth magnesium alloy yield strength of 358MPa, tensile strength of 389MPa, and elongation of 13% are obtained. The alloy strength of the magnesium alloy material is not high and cannot fully meet the current performance requirements for magnesium alloy structural parts. Therefore, it is particularly important to develop a new type of ultra-high strength magnesium alloy. Summary of the invention

[0004] In order to solve the current technical problem of low absolute mechanical strength of magnesium alloy materials, the present invention provides an ultra-high strength rare earth magnesium alloy deformation material. By adding Nd and Er elements and adjusting the ratio of each metal element in the alloy, the yield strength of the deformed magnesium alloy is 384MPa-388MPa, the tensile strength is 468MPa-474MPa, and the elongation is 8.5%-8.9%, showing excellent comprehensive mechanical properties.

[0005] The technical solution of the present invention is as follows:

[0006] The invention provides an ultra-high strength rare earth magnesium alloy deformation material, which is prepared from the following raw materials in mass fraction: Gd: 9.6%-10.4%, Y: 3.2%-4.3%, Zn: 1.4%-2.1%, Zr: 0.37%-0.51%, Nd: 0.4-0.7%, Er: 0.8%-1.2%, and the balance is Mg.

[0007] The present invention also provides a method for preparing the ultra-high strength rare earth magnesium alloy deformed material, comprising the following steps:

[0008] (1) Melting and casting: weighing raw materials according to the mass fraction of claim 1, melting and casting to obtain a magnesium alloy ingot;

[0009] (2) Homogenization treatment: The magnesium alloy ingot is placed at 500-510°C for 18-22 hours, then air-cooled and peeled;

[0010] (3) Variable speed isothermal extrusion treatment: preheating the magnesium alloy ingot after homogenization treatment to 450-460°C, preheating the mold to 390-410°C, maintaining the temperature of the magnesium alloy ingot above 400°C during the extrusion process, and extruding to obtain a rod;

[0011] (4) Aging treatment: The rod is placed at 190-210°C for 30-40 hours, then taken out for air cooling to obtain an ultra-high strength rare earth magnesium alloy deformed material.

[0012] In one embodiment of the present invention, it is also preferred that the raw materials used in step (1) are Mg ingots, Mg-30Gd master alloys, Mg-30Nd master alloys, Mg-30Y master alloys, Mg-30Zr master alloys, Mg-30Er master alloys and Zn ingots.

[0013] In one embodiment of the present invention, it is also preferred that the smelting and casting described in step (1) includes first placing the Mg ingot into the furnace for heating and melting, and passing protective gas, and when the furnace temperature rises to 710-750°C, adding Mg-30Gd intermediate alloy, Mg-30Y intermediate alloy and Zn ingot in sequence, and setting the furnace temperature to 740-750°C after keeping warm for 10 minutes, and continuing to keep warm for 15 minutes, and then adding Mg-30Zr intermediate alloy, Mg-30Nd intermediate alloy and Mg-30Er intermediate alloy in sequence, and continuing to keep warm for 15 minutes for refining, and continuing to stir to obtain alloy liquid, and casting the alloy liquid to obtain magnesium alloy ingot.

[0014] In one embodiment of the present invention, it is also preferred that when the extrusion treatment in step (3) includes extrusion processing, the extrusion ratio is 9-12.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The invention discloses a super high strength rare earth magnesium alloy deformed material. By adding Nd and Er elements and adjusting the ratio of each metal element in the Mg-Gd-Y-Zn-Zr alloy, 1) the rare earth Er has the same atomic stacking order as Mg, and has a close-packed hexagonal HCP structure. At the eutectic temperature of 570°C, it has a maximum mass solid solubility of 32.7% in Mg. Er can form three intermetallic compounds of Mg24Er5, Mg2Er and MgEr in the magnesium alloy. Therefore, as a rare earth element, it can also produce the effects of purifying alloy melt, improving alloy structure, improving alloy mechanical properties, and enhancing alloy corrosion resistance and creep resistance with other rare earth elements such as Gd, Y, Nd, etc. in the magnesium alloy. 2) The solid solubility of Nd element in Mg is relatively low, and the maximum solid solubility is about 3.7wt% at the eutectic temperature of 548°C and about 0.8wt% at room temperature. Adding Nd to Mg can produce obvious solid solution strengthening and aging hardening effects, and is an important element for improving the performance of magnesium alloys. Therefore, the magnesium alloy deformed material of the present invention exhibits excellent comprehensive mechanical properties, with a yield strength of 384 MPa-388 MPa, a tensile strength of 468 MPa-474 MPa, and an elongation of 8.5%-8.9%. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below.

[0018] Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited to the specific implementation disclosed below.

[0019] An ultra-high strength rare earth magnesium alloy deformed material according to an embodiment of the present invention comprises the following steps:

[0020] (1) Raw material selection: The raw materials used for the alloy are Mg ingot, Mg-30Gd master alloy, Mg-30Nd

[0021] Master alloy, Mg-30Y master alloy, Mg-30Zr master alloy, Mg-30Er master alloy and Zn ingot.

[0022] (2) First, place the Mg ingot in the furnace and heat it up to melt, and pass the protective gas. When the furnace temperature rises to 710-750°C, add the Mg-30Gd master alloy, Mg-30Y master alloy and Zn ingot in turn, keep the temperature for 10 minutes, set the furnace temperature to 740-750°C, continue to keep the temperature for 15 minutes, and then add the Mg-30Zr master alloy, Mg-30Nd in turn.

[0023] The intermediate alloy and the Mg-30Er intermediate alloy are kept warm for 15 minutes for refining and stirring, and the smelting is completed to obtain a molten alloy; then the molten alloy is cast into a magnesium alloy ingot.

[0024] (3) The magnesium alloy ingot is homogenized by keeping the temperature at 500°C-510°C for 18h-22h, followed by air cooling and peeling. The homogenization process is completed.

[0025] (4) During the variable speed isothermal extrusion process, the magnesium alloy ingot after homogenization treatment is preheated to 450℃-460℃, and the mold is preheated to 390-410℃ to ensure that the temperature is maintained above 400℃ during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 9-12.

[0026] (5) After the isothermal extrusion process is completed, an aging treatment is performed, and the process is as follows: the extruded rod is kept at 190-210°C for 30-40 hours, and then taken out for air cooling.

[0027] The profile variable speed isothermal extrusion technology adopted in the present invention adjusts the extrusion speed in real time based on process simulation, forms a near-isothermal forming environment, and obtains profiles that meet the index performance requirements.

[0028] Example 1

[0029] The method for preparing an ultra-high strength rare earth magnesium alloy deformed material according to embodiment 1 of the present invention comprises the following steps:

[0030] (1) In terms of mass percentage, the element composition of the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes: Gd: 10.4%, Y: 4.3%, Zn: 2.1%, Zr: 0.51%, Nd: 0.5%, Er: 1.0%, and the balance is Mg.

[0031] (2) The method for preparing the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes the following steps:

[0032] 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, pure Zn, Mg-30Zr, Mg-30Nd, and Mg-30Er. 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, Mg-30Y alloying elements, and pure Zn. After keeping warm for 10min, set the furnace temperature to 750℃, continue to keep warm for 15min, then put Mg-30Zr, Mg-30Nd, and Mg-30Er alloying elements, and continue to keep warm for 15min. Then, the refining and stirring are carried out, and the refining agent is 1.2% of the total weight of the ingredients, that is, 0.06kg. A small ingot is taken out 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.

[0033] The magnesium alloy ingot was placed in a muffle furnace at 510°C for 18 hours, followed by air cooling, peeling, and homogenization.

[0034] The magnesium alloy billet after homogenization is subjected to variable speed isothermal extrusion: the alloy billet is preheated to 460°C, the mold is preheated to 400°C, and the temperature is kept at about 400°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 10.

[0035] The extruded rod after isothermal extrusion was kept at 200°C for 36 hours and then taken out for air cooling.

[0036] At room temperature, according to the test requirements of GB-T 228-2002_Room Temperature Tensile Test Method for Metallic Materials, the yield strength of the deformed magnesium alloy was measured by a tensile mechanical properties testing machine to be 388 MPa, the tensile strength was 474 MPa, and the elongation was 8.5%.

[0037] The mechanical property tests of the following Examples 2 to 6 and Comparative Examples 1 to 2 were all conducted in accordance with GB-T228-2002_Metallic Materials Room Temperature Tensile Test Method.

[0038] Example 2

[0039] The method for preparing an ultra-high strength rare earth magnesium alloy deformed material according to embodiment 2 of the present invention comprises the following steps:

[0040] (1) In terms of mass percentage, the element composition of the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes: Gd: 9.6%, Y: 3.2%, Zn: 1.4%, Zr: 0.37%, Nd: 0.6%, Er: 1.2%, and the balance is Mg.

[0041] (2) The method for preparing the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes the following steps:

[0042] 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, pure Zn, Mg-30Zr, Mg-30Nd, and Mg-30Er. 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, Mg-30Y, and pure Zn. After keeping warm for 10min, set the furnace temperature to 750℃, continue to keep warm for 15min, then put Mg-30Zr, Mg-30Nd, and Mg-30Er alloying elements, and continue to keep warm for 15min. Then, the refining and stirring are carried out, and the refining agent is 1.2% of the total weight of the ingredients, that is, 0.06kg. A small ingot is taken out 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.

[0043] The magnesium alloy ingot was placed in a muffle furnace at 510°C for 18 hours, followed by air cooling, peeling, and homogenization.

[0044] The magnesium alloy billet after homogenization is subjected to variable speed isothermal extrusion: the alloy billet is preheated to 460°C, the mold is preheated to 400°C, and the temperature is kept at about 400°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 10.

[0045] The extruded rod after isothermal extrusion was kept at 200°C for 36 hours and then taken out for air cooling.

[0046] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 384 MPa, the tensile strength was 468 MPa, and the elongation was 8.9%.

[0047] Example 3

[0048] The method for preparing an ultra-high strength rare earth magnesium alloy deformed material according to Embodiment 3 of the present invention comprises the following steps:

[0049] (1) In terms of mass percentage, the element composition of the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes: Gd: 9.8%, Y: 4%, Zn: 2%, Zr: 0.4%, Nd: 0.4%, Er: 0.8%, and the balance is Mg.

[0050] (2) The method for preparing the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes the following steps:

[0051] 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, pure Zn, Mg-30Zr, Mg-30Nd, and Mg-30Er. Bake the batch and mold before smelting. Set the initial furnace temperature to 720℃, 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 720℃, pure Mg begins to melt after about 10min-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 740℃ again, add Mg-30Gd, Mg-30Y, and pure Zn. After keeping warm for 10min, set the furnace temperature to 750℃, continue to keep warm for 15min, then put Mg-30Zr, Mg-30Nd, and Mg-30Er alloying elements, and continue to keep warm for 15min. Then, the refining and stirring are carried out, and the refining agent is 1.2% of the total weight of the ingredients, that is, 0.06kg. A small ingot is taken out 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.

[0052] The magnesium alloy ingot was placed in a muffle furnace at 510°C for 18 hours, followed by air cooling, peeling, and homogenization.

[0053] The magnesium alloy billet after homogenization is subjected to variable speed isothermal extrusion: the alloy billet is preheated to 450°C, the mold is preheated to 400°C, and the temperature is kept at about 400°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 10.

[0054] The extruded rod after isothermal extrusion was kept at 200°C for 36 hours and then taken out for air cooling.

[0055] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 385 MPa, the tensile strength was 470 MPa, and the elongation was 8.7%.

[0056] Example 4

[0057] A method for preparing an ultra-high strength rare earth magnesium alloy deformed material according to embodiment 4 of the present invention comprises the following steps:

[0058] (1) In terms of mass percentage, the element composition of the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes: Gd: 9.8%, Y: 4%, Zn: 1.6%, Zr: 0.4%, Nd: 0.6%, Er: 1.2%, and the balance is Mg.

[0059] (2) The method for preparing the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes the following steps:

[0060] 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, pure Zn, Mg-30Zr, Mg-30Nd, and Mg-30Er. Bake the batch and mold before smelting. Set the initial furnace temperature to 720℃, 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 720℃, pure Mg begins to melt after about 10min-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 740℃ again, add Mg-30Gd, Mg-30Y, and pure Zn. After keeping warm for 10min, set the furnace temperature to 750℃, continue to keep warm for 15min, then put Mg-30Zr, Mg-30Nd, and Mg-30Er alloying elements, and continue to keep warm for 15min. Then, the refining and stirring are carried out, and the refining agent is 1.2% of the total weight of the ingredients, that is, 0.06kg. A small ingot is taken out 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.

[0061] The magnesium alloy ingot was placed in a muffle furnace at 510°C for 18 hours, followed by air cooling, peeling, and homogenization.

[0062] The magnesium alloy billet after homogenization is subjected to variable speed isothermal extrusion: the alloy billet is preheated to 460°C, the mold is preheated to 400°C, and the temperature is kept at about 400°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 10.

[0063] The extruded rod after isothermal extrusion was kept at 200°C for 36 hours and then taken out for air cooling.

[0064] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 382 MPa, the tensile strength was 469 MPa, and the elongation was 8.8%.

[0065] Example 5

[0066] A method for preparing an ultra-high strength rare earth magnesium alloy deformed material according to Embodiment 5 of the present invention comprises the following steps:

[0067] (1) In terms of mass percentage, the element composition of the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes: Gd: 10%, Y: 3.2%, Zn: 1.4%, Zr: 0.37%, Nd: 0.5%, Er: 1.2%, and the balance is Mg.

[0068] (2) The method for preparing the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes the following steps:

[0069] 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, pure Zn, Mg-30Zr, Mg-30Nd, and Mg-30Er. 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, Mg-30Y, and pure Zn. After keeping warm for 10min, set the furnace temperature to 750℃, continue to keep warm for 15min, then put Mg-30Zr, Mg-30Nd, and Mg-30Er alloying elements, and continue to keep warm for 15min. Then, the refining and stirring are carried out, and the refining agent is 1.2% of the total weight of the ingredients, that is, 0.06kg. A small ingot is taken out 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.

[0070] The magnesium alloy ingot was placed in a muffle furnace at 510°C for 18 hours, followed by air cooling, peeling, and homogenization.

[0071] The magnesium alloy billet after homogenization is subjected to variable speed isothermal extrusion: the alloy billet is preheated to 460°C, the mold is preheated to 400°C, and the temperature is kept at about 400°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 10.

[0072] The extruded rod after isothermal extrusion was kept at 200°C for 36 hours and then taken out for air cooling.

[0073] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 388 MPa, the tensile strength was 469 MPa, and the elongation was 8.6%.

[0074] Example 6

[0075] A method for preparing an ultra-high strength rare earth magnesium alloy deformed material according to embodiment 6 of the present invention comprises the following steps:

[0076] (1) In terms of mass percentage, the element composition of the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes: Gd: 9.6%, Y: 3.2%, Zn: 1.4%, Zr: 0.37%, Nd: 0.4%, Er: 0.8%, and the balance is Mg.

[0077] (2) The method for preparing the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes the following steps:

[0078] 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, pure Zn, Mg-30Zr, Mg-30Nd, and Mg-30Er. 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, Mg-30Y, and pure Zn. After keeping warm for 10min, set the furnace temperature to 750℃, continue to keep warm for 15min, then put Mg-30Zr, Mg-30Nd, and Mg-30Er alloying elements, and continue to keep warm for 15min. Then, the refining and stirring are carried out, and the refining agent is 1.2% of the total weight of the ingredients, that is, 0.06kg. A small ingot is taken out 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.

[0079] The magnesium alloy ingot was placed in a muffle furnace at 510°C for 18 hours, followed by air cooling, peeling, and homogenization.

[0080] The magnesium alloy billet after homogenization is subjected to variable speed isothermal extrusion: the alloy billet is preheated to 460°C, the mold is preheated to 400°C, and the temperature is kept at about 400°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 10.

[0081] The extruded rod after isothermal extrusion was kept at 200°C for 36 hours and then taken out for air cooling.

[0082] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 385 MPa, the tensile strength was 470 MPa, and the elongation was 8.9%.

[0083] Comparative Example 1

[0084] The preparation method of the magnesium alloy material of Comparative Example 1 comprises the following steps:

[0085] (1) In terms of mass percentage, the element composition of the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes: Gd: 10.0%, Y: 3.5%, Zn: 1.5%, Zr: 0.4%, and the balance is Mg.

[0086] (2) The method for preparing the deformed rare earth magnesium alloy material of Comparative Example 1 comprises the following steps:

[0087] 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, pure Zn, and Mg-30Zr. 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, Mg-30Y, and pure Zn. After keeping warm for 10min, set the furnace temperature to 750℃, continue to keep warm for 15min, then add Mg-30Zr alloying elements, and continue to keep warm for 15min. Then refine and stir, and the refining agent takes 1.2% of the total batch weight, that is, 0.06kg. 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.

[0088] The magnesium alloy ingot was placed in a muffle furnace at 510°C for 18 hours, followed by air cooling, peeling, and homogenization.

[0089] The magnesium alloy billet after homogenization is subjected to variable speed isothermal extrusion: the alloy billet is preheated to 460°C, the mold is preheated to 400°C, and the temperature is kept at about 400°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 10.

[0090] The extruded rod after isothermal extrusion was kept at 200°C for 36 hours and then taken out for air cooling.

[0091] At room temperature, the yield strength of the magnesium alloy deformed material was measured by a tensile mechanical properties testing machine to be 322 MPa, the tensile strength was 438 MPa, and the elongation was 7.2%.

[0092] Comparative Example 2

[0093] The preparation method of the magnesium alloy material of Comparative Example 2 comprises the following steps:

[0094] (1) In terms of mass percentage, the element composition of the ultra-high strength rare earth magnesium alloy deformed material of this embodiment includes: Gd: 10.0%, Y: 3.5%, Zn: 1.5%, Zr: 0.4%, Nd: 0.6%, and the balance is Mg.

[0095] (2) The method for preparing the rare earth magnesium alloy deformed material of this comparative example comprises the following steps:

[0096] 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, pure Zn, Mg-30Zr, and Mg-30Nd. 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, Mg-30Y, and pure Zn. After keeping warm for 10min, set the furnace temperature to 750℃, continue to keep warm for 15min, then put Mg-30Zr and Mg-30Nd alloying elements, and continue to keep warm for 15min. Then, the refining and stirring are carried out, and the refining agent is 1.2% of the total weight of the ingredients, that is, 0.06kg. A small ingot is taken out 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.

[0097] The magnesium alloy ingot was placed in a muffle furnace at 510°C for 18 hours, followed by air cooling, peeling, and homogenization.

[0098] The magnesium alloy billet after homogenization is subjected to variable speed isothermal extrusion: the alloy billet is preheated to 460°C, the mold is preheated to 400°C, and the temperature is kept at about 400°C during the extrusion process. During the extrusion process, the extrusion ratio is controlled at 10.

[0099] The extruded rod after isothermal extrusion was kept at 200°C for 36 hours and then taken out for air cooling.

[0100] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 326 MPa, the tensile strength was 445 MPa, and the elongation was 7.9%.

[0101] The component contents of Examples 1 to 6 are all within the scope of the component contents of the present invention, wherein, Comparative Example 1 does not add Nd and Er elements, and Comparative Example 2 does not add Er element. As shown in Table 1, it can be seen from the room temperature tensile mechanical property test results that the comprehensive mechanical properties of Examples 1 to 6 are significantly higher than those of Comparative Examples 1 to 2. In the field of magnesium alloy materials, it is difficult to further increase the absolute mechanical strength after reaching a limit value, especially the yield strength, tensile strength and elongation are all increased simultaneously. In the present invention, by adding Nd and Er elements to the Mg-Gd-Y-Zn-Zr alloy, the ratio of each metal element in the Mg-Gd-Y-Zn-Zr alloy is adjusted, and the yield strength is increased by nearly 60MPa, the tensile strength is increased by nearly 30MPa, and the elongation is increased to 8.5%-8.9%. Therefore, the magnesium alloy deformed material of the present invention exhibits excellent comprehensive mechanical properties, with a yield strength of 384MPa-388MPa, a tensile strength of 468MPa-474MPa, and an elongation of 8.5%-8.9%. Therefore, in the ultra-high strength rare earth magnesium alloy deformation of the present invention, adding Nd and Er elements to the Mg-Gd-Y-Zn-Zr series rare earth deformable magnesium alloy can significantly improve the comprehensive mechanical properties of the material and significantly improve the absolute strength.

[0102] Table 1 Room temperature mechanical properties of examples and comparative examples

[0103] Serial number Tensile strength(MPa) Yield strength (MPa) Elongation(%) Example 1 474 388 8.5 Example 2 468 384 8.9 Example 3 470 385 8.7 Example 4 469 382 8.8 Example 5 469 388 8.6 Example 6 470 385 8.9 Comparative Example 1 438 322 7.2 Comparative Example 2 445 326 7.9

[0104] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An ultra-high strength rare earth magnesium alloy deformed material, characterized in that: Made from the following raw materials by mass fraction: Gd: 9.6%-10.4%, Y: 3.2%-4.3%, Zn: 1.4%-2.1%, Zr: 0.37%-0.51%, Nd: 0.4-0.7%, Er: 0.8%-1.2%, the balance is Mg.

2. A method for preparing the ultra-high strength rare earth magnesium alloy deformed material according to claim 1, characterized in that: The following steps are involved: (1) Melting and casting: weighing raw materials according to the mass fraction of claim 1, melting and casting to obtain a magnesium alloy ingot; (2) Homogenization treatment: The magnesium alloy ingot is placed at 500-510°C for 18-22 hours, then air-cooled and peeled; (3) Variable speed isothermal extrusion treatment: preheating the magnesium alloy ingot after homogenization treatment to 450-460°C, preheating the mold to 390-410°C, maintaining the temperature of the magnesium alloy ingot above 400°C during the extrusion process, and extruding to obtain a rod; (4) Aging treatment: The rod is placed at 190-210°C for 30-40 hours, then taken out for air cooling to obtain an ultra-high strength rare earth magnesium alloy deformed material.

3. The method for preparing the ultra-high strength rare earth magnesium alloy deformed material according to claim 2, characterized in that: The raw materials used in step (1) are Mg ingots, Mg-30Gd master alloys, Mg-30Nd master alloys, Mg-30Y master alloys, Mg-30Zr master alloys, Mg-30Er master alloys and Zn ingots.

4. The method for preparing the ultra-high strength rare earth magnesium alloy deformed material according to claim 3, characterized in that: The smelting and casting described in step (1) include first placing the Mg ingot into a furnace for heating and melting, and passing a protective gas, and when the furnace temperature rises to 710-750°C, adding Mg-30Gd master alloy, Mg-30Y master alloy and Zn ingot in sequence, and setting the furnace temperature to 740-750°C after keeping warm for 10 minutes, and continuing to keep warm for 15 minutes, and then adding Mg-30Zr master alloy, Mg-30Nd master alloy and Mg-30Er master alloy in sequence, and continuing to keep warm for 15 minutes for refining, and continuing to stir to obtain alloy liquid, and casting the alloy liquid to obtain a magnesium alloy ingot.

5. The method for preparing the ultra-high strength rare earth magnesium alloy deformed material according to claim 2, characterized in that: The extrusion treatment in step (3) includes an extrusion process in which the extrusion ratio is 9-12.