High-toughness 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 a high-toughness rare earth magnesium alloy deformed material which is prepared from the following raw materials in percentage by mass: 5.1-7% of Sm, 1-3% of Yb, 0.6-1% of Zn, 0.4-0.6% of Zr and the balance of Mg. A preparation method comprises the steps of smelting and casting, homogenizing treatment, variable-speed isothermal extrusion treatment, aging treatment and the like. According to the rare earth magnesium alloy deformation material and the preparation method thereof, the Sm and Yb elements are added into the Mg-Zn-Zr series alloy, the proportion of all the metal elements in the alloy is adjusted, the rare earth magnesium alloy deformation material shows excellent comprehensive mechanical performance, the yield strength ranges from 459 MPa to 469 MPa, the tensile strength ranges from 477 MPa to 484 MPa, and the ductility ranges from 9.3% to 10.0%.

Description

Technical Field

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

[0002] At present, 70-90% of magnesium alloy applications are castings, mainly produced by high-pressure casting, while magnesium alloy deformed parts are less used. In 2004, global magnesium alloy extrusions accounted for less than 1.5% of the annual magnesium alloy products, and in 2013 it was still less than 3%. On the contrary, in the fields of infrastructure, automobiles and aerospace, about 25% of aluminum alloy components are processed by extrusion. However, the inherent disadvantages of cast magnesium alloys such as pores, cracks, inclusions, segregation, poor plasticity, and low strength will seriously limit their application in high-end equipment and load-bearing components. Therefore, the development of new low-cost high-strength deformable magnesium alloys is an inevitable development trend in the future. Summary of the invention

[0003] In order to solve the technical problem of low comprehensive mechanical properties of current magnesium alloy materials, the present invention provides a low-cost and high-toughness rare earth magnesium alloy deformed material. By adding Sm and Yb elements to the Mg-Zn-Zr alloy, the good aging precipitation effect of the Sm element and the effective reduction of Yb on the basal plane stacking fault energy of the alloy can be used to significantly improve the comprehensive mechanical properties of the alloy. The yield strength of the magnesium alloy deformed material of the present invention is 459MPa-469MPa, the tensile strength is 477-484MPa, and the elongation is 9.3-10.0%.

[0004] The present invention provides a low-cost and high-toughness rare earth magnesium alloy deformed material, which is prepared from the following raw materials in mass fraction: Sm: 5.1-7%, Yb: 1-3%, Zn: 0.6-1%, Zr: 0.4-0.6%, and the balance is Mg; the preparation method of the rare earth magnesium alloy deformed material comprises the following steps:

[0005] (1) Melting and casting: weighing raw materials according to the mass fraction of claim 1, melting and casting to obtain a magnesium alloy ingot;

[0006] (2) Homogenization treatment: The magnesium alloy ingot is subjected to solution treatment at 520-530°C for 2-4 hours, solution treatment at 510-520°C for 3-5 hours, quenching at 80-100°C, followed by air cooling and peeling.

[0007] (3) Variable speed isothermal extrusion treatment: preheating the magnesium alloy ingot after homogenization treatment to 300-320°C, preheating the mold to 290-310°C, maintaining the temperature of the magnesium alloy ingot above 300-320°C during the extrusion process, and extruding to obtain a rod;

[0008] (4) Aging treatment: The rod is placed at 190-210°C for 45-50 hours, then taken out for air cooling to obtain a low-cost, high-toughness rare earth magnesium alloy deformed material.

[0009] In one embodiment of the present invention, it is also preferred that the raw materials used in step (1) are Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys and Zn ingots.

[0010] 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 700-720°C, adding Mg-30Sm intermediate alloy, Mg-30Yb 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, 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.

[0011] 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 8-10.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The invention discloses a low-cost and high-toughness rare earth magnesium alloy deformed material. By adding Sm and Yb elements to the Mg-Zn-Zr alloy, the good aging precipitation effect of the Sm element and the effective reduction of the basal plane stacking fault energy of the alloy by Yb are utilized, so that the comprehensive mechanical properties of the magnesium alloy deformed material of the invention can be significantly improved, and the yield strength is 459MPa-469MPa, the tensile strength is 477-484MPa, and the elongation is 9.3-10.0%.

[0014] 1) Sm is a light rare earth with the highest solid solubility in magnesium (about 5.8wt.% at the eutectic temperature of 530°C), and its solid solubility gradually decreases with decreasing temperature, so Sm has a good aging strengthening effect in magnesium.

[0015] 2) Yb belongs to heavy rare earth, but it has the physical properties of light rare earth, such as large atomic radius and low solid solubility. Yb added to Mg-Zn-Zr alloy can reduce the basal plane stacking fault energy and promote Slip activity, activation<c+a> Slip and deformation twinning, thereby improving plasticity and work hardening. At the same time, Yb addition can improve the hot working properties of the alloy, reduce hot cracking, and improve the forming performance of the alloy.

[0016] 3) Compared with the commonly used rare earths Gd, Y and Nd, Sm and Yb have the significant advantage of low cost; extrusion at a lower temperature is also relatively cost-effective and easy to realize industrial application. 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 implementation methods of the present invention are described in detail below in conjunction with embodiments.

[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] A low-cost and high-toughness rare earth magnesium alloy deformed material according to an embodiment of the present invention comprises the following steps:

[0020] (1) Selection of raw materials: The raw materials used for the alloy are Mg ingot, Mg-30Sm master alloy, Mg-25Yb master alloy, Mg-30Zr master alloy and Zn ingot.

[0021] (2) First, Mg ingots are placed in a furnace for heating and melting, and protective gas is passed through. When the furnace temperature rises to 700-720°C, Mg-30Sm master alloy, Mg-30Yb master alloy and Zn ingots are added in sequence. After keeping the temperature for 10 minutes, the furnace temperature is set to 740-750°C, and the temperature is kept for 15 minutes. Then, Mg-30Zr master alloy is added, and the temperature is kept for 15 minutes for refining. The alloy liquid is obtained by stirring, and the alloy liquid is cast to obtain a magnesium alloy ingot.

[0022] (3) The magnesium alloy ingot is homogenized, and the process is as follows: the magnesium alloy ingot is successively placed at 520-530°C for solution treatment for 2-4 hours, at 510-520°C for solution treatment for 3-5 hours, and then quenched at 80-100°C, followed by air cooling and peeling.

[0023] (4) During the variable speed isothermal extrusion process, the magnesium alloy ingot after homogenization is preheated to 300-320°C, and the mold is preheated to 290-310°C. During the extrusion process, the temperature of the magnesium alloy ingot is maintained above 300-320°C. The rod is extruded and the extrusion ratio is controlled at 8-10.

[0024] (5) After the isothermal extrusion process is completed, an aging treatment is performed, wherein the rod is placed at 190-210°C for 45-50 hours, and then taken out for air cooling to obtain a low-cost, high-toughness rare earth magnesium alloy deformed material.

[0025] Example 1

[0026] A low-cost and high-toughness rare earth magnesium alloy deformed material according to Example 1 of the present invention comprises the following steps:

[0027] (1) In terms of mass percentage, the element composition of the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 1 includes: Sm: 7%, Yb: 3%, Zn: 1%, Zr: 0.6%, and the balance is Mg.

[0028] (2) The method for preparing the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 1 includes the following steps:

[0029] 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 Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy, Mg-25Yb master alloy, and Zn ingot in turn; keep warm for 10min, set the furnace temperature to 740℃, continue to keep warm for 15min, and Mg-30Zr master alloy, 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.

[0030] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°; followed by air cooling and peeling, and the homogenization treatment was completed.

[0031] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0032] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0033] 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 463 MPa, the tensile strength was 484 MPa, and the elongation was 9.3%.

[0034] The mechanical property tests of the following Examples 2 to 8 and Comparative Examples 1 to 2 were all conducted in accordance with GB-T228-2002_Metallic Materials Room Temperature Tensile Test Method.

[0035] Example 2

[0036] A low-cost and high-toughness rare earth magnesium alloy deformed material according to Embodiment 2 is prepared by a method comprising the following steps:

[0037] (1) In terms of mass percentage, the element composition of the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 2 includes: Sm: 5.1%, Yb: 1%, Zn: 0.6%, Zr: 0.4%, and the balance is Mg.

[0038] (2) The method for preparing the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 2 includes the following steps:

[0039] 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 Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy, Mg-25Yb master alloy, and Zn ingot in turn; keep warm for 10min, set the furnace temperature to 740℃, continue to keep warm for 15min, and Mg-30Zr master alloy, 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.

[0040] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°C; followed by air cooling and peeling, and the homogenization treatment was completed.

[0041] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0042] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0043] At room temperature, the yield strength of the magnesium alloy deformed material was measured by a tensile mechanical properties testing machine to be 459 MPa, the tensile strength was 477 MPa, and the elongation was 10.0%.

[0044] Example 3

[0045] A low-cost and high-toughness rare earth magnesium alloy deformed material according to Embodiment 3 is prepared by a method comprising the following steps:

[0046] (1) In terms of mass percentage, the element composition of the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 3 includes: Sm: 5.1%, Yb: 1%, Zn: 1%, Zr: 0.6%, and the balance is Mg.

[0047] (2) The method for preparing the low-cost and high-toughness rare earth magnesium alloy deformed material of this embodiment 3 includes the following steps:

[0048] 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 Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy, Mg-25Yb master alloy, and Zn ingot in turn; keep warm for 10min, set the furnace temperature to 740℃, continue to keep warm for 15min, and Mg-30Zr master alloy, 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.

[0049] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°; followed by air cooling and peeling, and the homogenization treatment was completed.

[0050] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0051] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0052] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 463 MPa, the tensile strength was 482 MPa, and the elongation was 9.6%.

[0053] Example 4

[0054] A low-cost and high-toughness rare earth magnesium alloy deformed material according to Embodiment 4 is prepared by a method comprising the following steps:

[0055] (1) In terms of mass percentage, the element composition of the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 4 includes: Sm: 5.1%, Yb: 3%, Zn: 1%, Zr: 0.6%, and the balance is Mg.

[0056] (2) The method for preparing the low-cost and high-toughness rare earth magnesium alloy deformed material of this embodiment 4 includes the following steps:

[0057] 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 Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy, Mg-25Yb master alloy, and Zn ingot in turn; keep warm for 10min, set the furnace temperature to 740℃, continue to keep warm for 15min, and Mg-30Zr master alloy, 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.

[0058] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°; followed by air cooling and peeling, and the homogenization treatment was completed.

[0059] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0060] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0061] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 466 MPa, the tensile strength was 480 MPa, and the elongation was 9.7%.

[0062] Example 5

[0063] A low-cost and high-toughness rare earth magnesium alloy deformed material according to Embodiment 5 is prepared by a method comprising the following steps:

[0064] (1) In terms of mass percentage, the element composition of the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 5 includes: Sm: 6%, Yb: 2%, Zn: 1%, Zr: 0.6%, and the balance is Mg.

[0065] (2) The method for preparing the low-cost and high-toughness rare earth magnesium alloy deformed material of this embodiment 5 includes the following steps:

[0066] 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 Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy, Mg-25Yb master alloy, and Zn ingot in turn; keep warm for 10min, set the furnace temperature to 740℃, continue to keep warm for 15min, and Mg-30Zr master alloy, 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.

[0067] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°; followed by air cooling and peeling, and the homogenization treatment was completed.

[0068] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0069] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0070] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 467 MPa, the tensile strength was 483 MPa, and the elongation was 9.8%.

[0071] Example 6

[0072] A low-cost and high-toughness rare earth magnesium alloy deformed material according to Embodiment 6 is prepared by a method comprising the following steps:

[0073] (1) In terms of mass percentage, the element composition of the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 6 includes: Sm: 7%, Yb: 3%, Zn: 0.6%, Zr: 0.4%, and the balance is Mg, and the balance is Mg.

[0074] (2) The method for preparing the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 6 includes the following steps:

[0075] 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 Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy, Mg-25Yb master alloy, and Zn ingot in turn; keep warm for 10min, set the furnace temperature to 740℃, continue to keep warm for 15min, and Mg-30Zr master alloy, 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.

[0076] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°; followed by air cooling and peeling, and the homogenization treatment was completed.

[0077] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0078] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0079] At room temperature, the yield strength of the magnesium alloy deformed material was measured by a tensile mechanical properties testing machine to be 468 MPa, the tensile strength was 482 MPa, and the elongation was 9.5%.

[0080] Example 7

[0081] A low-cost and high-toughness rare earth magnesium alloy deformed material according to Embodiment 7 is prepared by a method comprising the following steps:

[0082] (1) In terms of mass percentage, the element composition of the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 7 includes: Sm: 7%, Yb: 1%, Zn: 0.6%, Zr: 0.4%, and the balance is Mg.

[0083] (2) The method for preparing the low-cost and high-toughness rare earth magnesium alloy deformed material of this embodiment 7 comprises the following steps:

[0084] 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 Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy, Mg-25Yb master alloy, and Zn ingot in turn; keep warm for 10min, set the furnace temperature to 740℃, continue to keep warm for 15min, and Mg-30Zr master alloy, 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.

[0085] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°; followed by air cooling and peeling, and the homogenization treatment was completed.

[0086] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0087] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0088] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 468 MPa, the tensile strength was 482 MPa, and the elongation was 9.8%.

[0089] Example 8

[0090] A low-cost and high-toughness rare earth magnesium alloy deformed material according to Embodiment 8 is prepared by a method comprising the following steps:

[0091] (1) In terms of mass percentage, the element composition of the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 8 includes: Sm: 6%, Yb: 2%, Zn: 0.6%, Zr: 0.4%, and the balance is Mg.

[0092] (2) The method for preparing the low-cost and high-toughness rare earth magnesium alloy deformed material of Example 8 includes the following steps:

[0093] 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 Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy, Mg-25Yb master alloy, and Zn ingot in turn; keep warm for 10min, set the furnace temperature to 740℃, continue to keep warm for 15min, and Mg-30Zr master alloy, 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.

[0094] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°; followed by air cooling and peeling, and the homogenization treatment was completed.

[0095] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0096] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0097] At room temperature, the yield strength of the deformed magnesium alloy material was measured by a tensile mechanical properties testing machine to be 465 MPa, the tensile strength was 481 MPa, and the elongation was 9.7%.

[0098] Comparative Example 1

[0099] The preparation method of the magnesium alloy material of Comparative Example 1 comprises the following steps:

[0100] Calculated in mass percentage, the element composition of the rare earth magnesium alloy material of Comparative Example 1 includes: Sm: 5.1%, Zn: 0.6%, Zr: 0.4%, and the balance is Mg.

[0101] (1) The preparation method of the rare earth magnesium alloy material of this comparative example 1 comprises the following steps:

[0102] 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 Mg ingots, Mg-30Sm master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15 minutes, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy and Zn ingot in turn; keep the temperature for 10 minutes and set the furnace temperature to 740℃, continue to keep the temperature for 15 minutes, and Mg-30Zr master alloy, and continue to keep the temperature for 15 minutes. 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.

[0103] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°C; followed by air cooling and peeling, and the homogenization treatment was completed.

[0104] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0105] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0106] At room temperature, the alloy yield strength of the magnesium alloy deformed material was measured by a tensile mechanical properties testing machine to be 310 MPa, the tensile strength was 394 MPa, and the elongation was 12.2%.

[0107] Comparative Example 2

[0108] The preparation method of the magnesium alloy material of Comparative Example 2 comprises the following steps:

[0109] (1) In terms of mass percentage, the element composition of the rare earth magnesium alloy material of Comparative Example 2 includes: Sm: 8%, Yb: 4%, Zn: 0.6%, Zr: 0.4%, and the balance is Mg.

[0110] (2) The preparation method of the rare earth magnesium alloy material of this comparative example 2 comprises the following steps:

[0111] 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 Mg ingots, Mg-30Sm master alloys, Mg-25Yb master alloys, Mg-30Zr master alloys, and Zn ingots. Bake the batches and molds 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 10-15min, and the furnace temperature drops to 670℃. When the melt temperature rises to 750℃ again, add Mg-30Sm master alloy, Mg-25Yb master alloy, and Zn ingot in turn; keep warm for 10min, set the furnace temperature to 740℃, continue to keep warm for 15min, and Mg-30Zr master alloy, 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.

[0112] The magnesium alloy ingot was homogenized by solution treatment at 525°C for 2 hours, then solution treatment at 515°C for 4 hours, and finally quenched at 80°C; followed by air cooling and peeling, and the homogenization treatment was completed.

[0113] The variable speed isothermal hot extrusion process is performed, the magnesium alloy ingot after homogenization treatment is preheated to 300-320°C, and the mold is preheated to 300°C to ensure that the temperature is maintained at 300-320°C during the extrusion process; when performing the extrusion process, the extrusion ratio is controlled at 8-10.

[0114] After the isothermal extrusion process is completed, the extruded rod is kept at 200°C for 48 hours and then taken out for air cooling.

[0115] At room temperature, the alloy yield strength of the magnesium alloy deformed material was measured by a tensile mechanical properties testing machine to be 333 MPa, the tensile strength was 444 MPa, and the elongation was 4.3%.

[0116] The component contents of Examples 1 to 8 are all within the component content range of the present invention, wherein no Yb element is added, and an excessive amount of Sm and Yb elements are added in Comparative Example 2, and the rest are the same as Example 2. 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 8 are significantly higher than those of Comparative Examples 1 to 2. In the field of magnesium alloy materials, it is difficult to 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, Sm and Yb elements are added to the Mg-Zn-Zr alloy, and the ratio of each metal element in the Mg-Zn-Zr alloy is adjusted. Compared with Comparative Examples 1 to 2, the yield strength is increased by nearly 140MPa, the tensile strength is increased by nearly 80MPa, and the elongation is increased by nearly 5%. Therefore, the magnesium alloy deformed material of the present invention exhibits excellent comprehensive mechanical properties, with a yield strength of 459MPa-469MPa, a tensile strength of 477-484MPa, and an elongation of 9.3-10.0%. Therefore, in the ultra-high strength rare earth magnesium alloy deformation of the present invention, adding Sm and Yb elements to the Mg-Zn-Zr series rare earth deformable magnesium alloy can significantly improve the comprehensive mechanical properties of the material and significantly improve the absolute strength.

[0117] Table 1 Room temperature mechanical properties of the embodiments and comparative examples

[0118] Serial number Tensile strength(MPa) Yield strength(MPa) Elongation(%) Example 1 463 484 9.3 Example 2 459 477 10.0 Example 3 463 482 9.6 Example 4 466 480 9.7 Example 5 467 483 9.8 Example 6 468 482 9.5 Example 7 468 482 9.8 Example 8 465 481 9.7 Comparative Example 1 310 394 12.2 Comparative Example 2 333 444 4.3

[0119] 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. A high-toughness rare earth magnesium alloy deformed material, characterized in that: The rare earth magnesium alloy deformed material is prepared from the following raw materials in mass fraction: Sm: 5.1-7%, Yb: 1-3%, Zn: 0.6-1%, Zr: 0.4-0.6%, and the balance is Mg; the preparation method of the rare earth magnesium alloy deformed material comprises the following steps: (1) Melting and casting: weighing raw materials according to the mass fraction of claim 1, melting and casting to obtain magnesium alloy ingots; (2) Homogenization treatment: The magnesium alloy ingot is placed in a solution state at 520-530°C for 2-4 hours, then in a solution state at 510-520°C for 3-5 hours, then quenched at 80-100°C, then air-cooled, and then peeled; (3) Variable speed isothermal extrusion treatment: preheat the magnesium alloy ingot after homogenization treatment to 300-320°C, preheat the mold to 290-310°C, keep the temperature of the magnesium alloy ingot above 300-320°C during the extrusion process, and extrude to obtain a rod; (4) Aging treatment: Place the rod at 190-210°C for 45-50 hours, then take it out for air cooling to obtain a high-toughness rare earth magnesium alloy deformed material.

2. The high-toughness rare earth magnesium alloy deformed material according to claim 1, characterized in that: The raw materials used in step (1) are Mg ingot, Mg-30Sm master alloy, Mg-25Yb master alloy, Mg-30Zr master alloy and Zn ingot.

3. The high-toughness rare earth magnesium alloy deformed material according to claim 2, characterized in that: The smelting and casting described in step (1) comprises first placing the Mg ingot into a furnace for heating and melting, and passing a protective gas, and when the furnace temperature rises to 700-720°C, sequentially adding the Mg-30Sm master alloy, the Mg-30Yb master alloy and the Zn ingot, and setting the furnace temperature to 740-750°C after keeping the temperature for 10 minutes, and continuing to keep the temperature for 15 minutes, and then adding the Mg-30Zr master alloy, and continuing to keep the temperature for 15 minutes for refining, and continuing to stir to obtain a molten alloy, and casting the molten alloy to obtain a magnesium alloy ingot.

4. The high-toughness rare earth magnesium alloy deformed material according to claim 1, characterized in that: The extrusion treatment in step (3) includes an extrusion process in which the extrusion ratio is 8-10.