MG-AL MAGNESIUM ALLOY, PREPARATION METHOD FOR TUBE MADE OF MG-AL MAGNESIUM ALLOY, APPLICATION OF MG-AL MAGNESIUM ALLOY

Abstract

The present disclosure discloses a MgAl based magnesium alloy, and a preparation method of a tube and an application of the same, and belongs to the technical field of alloy materials. The magnesium alloy includes, by weight percentage, 7.0-8.6% Al, 0.8-2.0% RE, 0.2-0.8% Mn, and a balance of Mg, and the magnesium alloy has an elongation of 15-22%. The preparation method of a tube of the MgAl based magnesium alloy includes: mixing and smelting an Al source, a RE source, a Mn source, and a Mg source to give a liquid mixed metal; casting the liquid mixed metal into a bar through semi-continuous casting; performing homogenization heat treatment on the bar at 360-400 C. for 6-10 h; and performing extrusion-forming on the heat-treated bar to obtain a magnesium alloy tube. The MgAl based magnesium alloy of the present disclosure has high elongation, and the elongation of the tube formed using the same can reach 15-22%, so that it can withstand large plastic deformation. Meanwhile, the MgAl based magnesium alloy has excellent welding performance and a welding loss rate of less than 6%, which greatly reduces the strength loss of magnesium alloy profiles after welding, and ensures the strength of magnesium alloy profiles after welding. The MgAl based magnesium alloy can be used in the fields of vehicle equipment and medical equipment.

Claims

1. A MgAl based magnesium alloy comprising, by weight percentage, 7.0-8.6% Al, 0.8-2.0% RE, 0.2-0.8% Mn, and a balance of Mg, the magnesium alloy having an elongation of 15-22%.

2. The MgAl based magnesium alloy according to claim 1, wherein in the magnesium alloy, the weight percentage of Al is 7.0-8.2%, the weight percentage of RE is 1.1-2.0%, and the weight percentage of Mn is 0.4-0.8%.

3. The MgAl based magnesium alloy according to claim 2, wherein in the magnesium alloy, the weight percentage of Al is 7.8-8.2%, the weight percentage of RE is 1.3-1.9%, and the weight percentage of Mn is 0.5-0.8%; and in the RE, the weight percentage of Y is 0.8-1.6%, and the mass percentage of Ce is 0-0.8%.

4. The MgAl based magnesium alloy according to claim 1, wherein the magnesium alloy has an elongation of 17-21.6%.

5. The MgAl based magnesium alloy according to claim 1, wherein the magnesium alloy has a welding loss rate of less than 6%.

6. The MgAl based magnesium alloy according to claim 1, wherein the magnesium alloy has a yield strength of 182-235 MPa and a tensile strength of 306-342 MPa.

7. The MgAl based magnesium alloy according to claim 1, wherein the RE comprises at least one of La, Ce, Nd, Y, Gd, Ho, Dy, and Er.

8. A preparation method of a tube of a MgAl based magnesium alloy, comprising steps of: mixing an Al source, a RE source, a Mn source, and a Mg source in element weight percentage contents of 7.0-8.6% Al, 0.8-2.0% RE, 0.2-0.8% Mn, and a balance of Mg to obtain a mixture, and smelting the mixture to give a liquid mixed metal; casting the liquid mixed metal into a bar through semi-continuous casting; performing homogenization heat treatment on the bar at 360-400 C. for 6-10 h; and performing back extrusion forming on the heat-treated bar to obtain the magnesium alloy tube.

9. An application of the MgAl based magnesium alloy according to any one of claim 1 in fields of vehicle equipment and medical equipment.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is a flow chart of a preparation process of the MgAl based magnesium alloy of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The technical solutions of the present disclosure will be further described below with reference to the accompanying drawings and examples.

[0023] A MgAl based magnesium alloy of the present disclosure includes, by weight percentage, 7.0-8.6% Al, 0.8-2.0% RE, 0.2-0.8% Mn, and a balance of Mg.

[0024] Specifically, in the magnesium alloy of the present disclosure, RE (rare earth element) and Mn are added to a MgAl based alloy with components in a certain proportion, thereby improving the plasticity and strength of the magnesium alloy and reducing the welding loss rate of the alloy.

[0025] Addition of Mn allows removing the impurity element Fe introduced during semi-continuous casting, which is advantageous to welding performance and mechanical properties, thereby reducing the welding loss rate. Meanwhile, Mn does not form a compound in magnesium, and can be used as heterogeneous nucleation particles to refine grains. When the alloy is extruded into a tube, Mn promotes dynamic recrystallization, refines grains, and weakens texture, thereby improving strength and plasticity.

[0026] The addition of RE can refine the grain size of the magnesium alloy, improve the morphology of the strengthening phase of the magnesium alloy, and enhance the strength and plasticity of the magnesium alloy. The strength of the magnesium alloy can be reflected by the yield strength and tensile strength. After the MgAl based magnesium alloy provided by the present disclosure is formed into a tube, the range of the yield strength of the tube is 182-235 MPa, and preferably the range of the yield strength of the tube is 220-235 MPa. Meanwhile, the tensile strength of the MgAl based magnesium alloy tube ranges from 306 to 342 MPa, preferably 320 to 340 MPa. The elongation has a direct correlation to the plasticity of the magnesium alloy. After the MgAl based magnesium alloy provided by the present disclosure is formed into a tube, the elongation of the tube can reach 15-22%, and preferably the elongation of the MgAl based magnesium alloy tube is 17-21.6%. A high elongation allows the magnesium alloy to withstand large plastic deformation and improves the application range of the magnesium alloy.

[0027] The welding strength loss rate is the strength loss rate of the welded sample compared to the original profile sample after the magnesium alloy profile is welded. The welding strength loss rate of the MgAl based magnesium alloy provided by the present disclosure is less than 6%, preferably, the welding strength loss rate is less than 5%, and more preferably, the welding strength loss rate is less than 4.3%. In the magnesium alloy provided by the examples of the present disclosure, due to the addition of RE element, Al-RE high-temperature stable phase is formed during high temperature welding, and the high-temperature stable phase is pinned at the grain boundary, which hinders the growth of magnesium alloy grains during the welding process. Furthermore, the RE element can greatly reduce/refine the size of the strengthening phase in the magnesium alloy, and avoid the growth of the strengthening phase in the high temperature welding process, thereby reducing the strength loss of the magnesium alloy profile after welding, and ensuring the strength of the magnesium alloy profile after welding.

[0028] Optionally, the range of the weight percentage of Al in the MgAl based magnesium alloy of the present disclosure is 7.0-8.6%, preferably the range of the weight percentage of Al in the MgAl based magnesium alloy is 7.0-8.2%, and more preferably, the range of the weight percentage of Al is 7.8-8.2%.

[0029] Specifically, when the weight percentage of Al in the MgAl based magnesium alloy is controlled within a certain range, the combination of Al and Mg elements has a second-phase strengthening effect, and during the formation process of the magnesium alloy, the strengthening phase can achieve the optimum state (moderate volume fraction, morphology, and size), thereby improving the strength of magnesium alloys. Meanwhile, the Al element as a solid solution part in the magnesium matrix can play a role in solid solution strengthening and improving plasticity. When the weight percentage of Al in the MgAl based magnesium alloy is extremely high, for example, the weight percentage of Al in the MgAl based magnesium alloy is greater than 8.6%, due to the precipitation of the coarse eutectic phase, on the one hand, after welding, the interface bonding ability between the precipitated phase and the matrix is weakened, and microscopic pores are easily formed at the interface between the matrix and the phase, which increase the welding loss rate; and on the other hand, the coarse phase may cause, in the course of service, stress concentration, advance occurrence of plastic instability and reduced elongation. When the weight percentage of Al in the magnesium alloy is extremely low, for example, less than 7%, the reduction of the Al element in the crystal is not conducive to improving the plasticity, and meanwhile, the amount of precipitated phase is less, and the degree of refinement of grains is reduced, causing the second phase strengthening effect not to be exhibited, which is not conducive to the improvement of the strength of the magnesium alloy. In addition, for the alloy containing less precipitated phase after welding, the grain growth is more obvious, thus causing the welding loss rate to increase.

[0030] Optionally, the range of the weight percentage of RE in the MgAl based magnesium alloy of the present disclosure is 0.8-2.0%, preferably, the range of the weight percentage of RE in the MgAl based magnesium alloy is 1.1-2.0%, and more preferably, the range of the weight percentage of RE is 1.3-1.9%. Specifically, after RE is added to the MgAl based magnesium alloy, since the RE element has a unique electronic arrangement structure and chemical characteristics, addition of an appropriate amount of rare earth elements to the magnesium alloy can enhance the interatomic bonding force, reduce the diffusion rate of magnesium atoms, increase the recrystallization temperature of the magnesium alloy, slow down the recrystallization growth rate, and significantly improve the formability and corrosion resistance of the magnesium alloy. Further, RE is generally distributed in the grain boundaries and can reduce the grain size of the magnesium alloy and improve coordination ability between the grains of the magnesium alloy. RE can also form a thermally stable p strengthening phase during the formation process of the magnesium alloy, which improves the strength and plasticity of the magnesium alloy.

[0031] RE may include at least one of La, Ce, Nd, Y, Gd, Ho, Dy, and Er. Specifically, the RE elements in the MgAl based magnesium alloy of the present disclosure are mainly Y and Ce. The weight percentage of Y ranges from 0.8% to 1.6%, and the weight percentage of Ce ranges from 0 to 0.8%.

[0032] In FIG. 1, the present disclosure provides a preparation method of the MgAl based magnesium alloy, comprising steps of: [0033] S101, mixing an Al source, a RE source, a Mn source, and a Mg source in element weight percentage contents of 7.0-8.6% Al, 0.8-2.0% RE, 0.2-0.8% Mn and a balance of Mg, and smelting the mixture to give a liquid mixed metal; [0034] S102, casting the liquid mixed metal into an ingot; [0035] S103, performing homogenization heat treatment on the ingot at a first temperature; and [0036] S104, performing extrusion-forming on the heat-treated ingot to obtain the MgAl based magnesium alloy of the present disclosure.

[0037] Specifically, the casting process in S102 can be implemented by a semi-continuous casting process. With the semi-continuous process, due to rapid water cooling, the size of obtained grains is small, and the fine grains can improve both the strength and the elongation of the alloy. In S103, the first temperature ranges from 360 C. to 400 C., and the heat treatment time is 6-10 h. The heat treatment process before extrusion can increase the content of Al element in the matrix, increase the slip system, and improve the elongation of the alloy.

[0038] When preparing the MgAl based magnesium alloy tube, in step S102, the ingot is cast into a bar, that is, the liquid mixed metal is cast into a bar; and in step S104, the heat-treated bar is subjected to back extrusion forming to obtain a MgAl based magnesium alloy tube. The process parameters of back extrusion forming include extrusion temperature, extrusion ratio, and extrusion speed, among which the extrusion temperature ranges from 280 C. to 330 C., the extrusion ratio is 49:1, and the extrusion speed ranges 8 mm/s to 15 mm/s.

[0039] Taking the preparation of MgAl based magnesium alloy tubes as an example, the magnesium alloy provided by the present disclosure will be described in detail through the following specific examples and comparative examples. The magnesium alloy tubes obtained by the preparation method provided in the examples of the present disclosure have a large elongation and can withstand large plastic deformation, and the magnesium alloy tubes have a low welding loss rate, and these properties improve the application range of the magnesium alloy. Also, the magnesium alloy has higher yield strength and tensile strength.

Example 1

[0040] A MgAl based magnesium alloy included: 7 g Al, 0.8 g Y, 0.5 g Mn, and 91.7 g Mg.

[0041] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0042] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0043] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0044] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0045] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 2

[0046] A MgAl based magnesium alloy included: 7.4 g Al, 0.8 g Y, 0.5 g Mn, and 91.3 g Mg.

[0047] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0048] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0049] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0050] S103, the bar was heat-treated at 360 C. for a treatment duration of 10 h; and [0051] S104, the heat-treated bar was back-extruded at a speed of 8 mm/s and an extrusion temperature of 280 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 3

[0052] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Mn, and 91.9 g Mg.

[0053] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0054] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0055] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0056] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0057] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 4

[0058] A MgAl based magnesium alloy included: 8.2 g Al, 0.8 g Y, 0.5 g Mn, and 90.5 g Mg.

[0059] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0060] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0061] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0062] S103, the bar was heat-treated at 380 C. for a treatment duration of 6 h; and [0063] S104, the heat-treated bar was back-extruded at a speed of 10 mm/s and an extrusion temperature of 330 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 5

[0064] A MgAl based magnesium alloy included: 8.6 g Al, 0.8 g Y, 0.5 g Mn, and 90.1 g Mg.

[0065] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0066] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0067] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0068] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0069] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 6

[0070] A MgAl based magnesium alloy included: 7.8 g Al, 1.2 g Y, 0.5 g Mn, and 90.5 g Mg.

[0071] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0072] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0073] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0074] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0075] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 7

[0076] A MgAl based magnesium alloy included: 7.8 g Al, 1.6 g Y, 0.5 g Mn, and 90.1 g Mg.

[0077] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0078] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0079] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0080] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0081] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 8

[0082] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.3 g Ce (RE 1.1%), 0.5 g Mn, and 90.6 g Mg.

[0083] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0084] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0085] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0086] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0087] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 9

[0088] A MgAl based magnesium alloy included: 7.8 g Al, 1.2 g Y, 0.3 g Ce (RE 1.5%), 0.5 g Mn, and 90.2 g Mg.

[0089] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0090] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0091] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0092] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0093] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 10

[0094] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce (RE 1.3%), 0.5 g Mn, and 90.4 g Mg.

[0095] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0096] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0097] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0098] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0099] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 11

[0100] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.8 g Ce (RE 1.6%), 0.5 g Mn, and 90.1 g Mg.

[0101] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0102] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0103] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0104] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0105] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 12

[0106] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce, 0.1 g La (RE 1.4%), 0.5 g Mn, and 90.3 g Mg.

[0107] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0108] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0109] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0110] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0111] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 13

[0112] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce, 0.1 g La, 0.1 g Nd (RE 1.5%), 0.5 g Mn, and 90.2 g Mg.

[0113] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0114] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0115] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0116] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0117] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 14

[0118] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce, 0.1 g La, 0.1 g Nd, 0.1 g Gd (RE 1.6%), 0.5 g Mn, and 90.1 g Mg.

[0119] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0120] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0121] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0122] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0123] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 15

[0124] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce, 0.1 g La, 0.1 g Nd, 0.1 g Gd, 0.1 Ho (RE 1.7%), 0.5 g Mn, and 90.1 g Mg.

[0125] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0126] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0127] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0128] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0129] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 16

[0130] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce, 0.1 g La, 0.1 g Nd, 0.1 g Gd, 0.1 Ho, 0.1 Dy (RE 1.8%), 0.5 g Mn, and 90.0 g Mg.

[0131] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0132] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0133] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0134] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0135] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 17

[0136] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce, 0.1 g La, 0.1 g Nd, 0.1 g Gd, 0.1 Ho, 0.1 Dy, 0.1 Er (RE 1.9%), 0.5 g Mn, and 89.9 g Mg.

[0137] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0138] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0139] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0140] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0141] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 18

[0142] A MgAl based magnesium alloy included: 8.0 g Al, 0.8 g Y, 0.5 g Ce (RE 1.3%), 0.5 g Mn, and 90.4 g Mg.

[0143] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0144] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0145] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0146] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0147] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 19

[0148] A MgAl based magnesium alloy included: 8.0 g Al, 0.8 g Y, 0.5 g Ce, 0.1 g La, 0.1 g Nd, 0.1 g Gd, 0.1 Ho, 0.1 Dy, 0.1 Er (RE 1.9%), 0.5 g Mn, and 89.6 g Mg.

[0149] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0150] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0151] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0152] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0153] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 20

[0154] A MgAl based magnesium alloy included: 8.2 g Al, 0.8 g Y, 0.5 g Ce, 0.1 g La, 0.1 g Nd, 0.1 g Gd (RE 1.6%), 0.5 g Mn, and 89.7 g Mg.

[0155] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0156] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0157] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0158] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0159] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 21

[0160] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce (RE 1.3%), 0.2 g Mn, and 90.7 g Mg.

[0161] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0162] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0163] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0164] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0165] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 22

[0166] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce (RE 1.3%), 0.4 g Mn, and 90.5 g Mg.

[0167] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0168] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0169] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0170] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0171] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Example 23

[0172] A MgAl based magnesium alloy included: 7.8 g Al, 0.8 g Y, 0.5 g Ce (RE 1.3%), 0.8 g Mn, and 90.1 g Mg.

[0173] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0174] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0175] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0176] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0177] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Comparative Example 1

[0178] A MgAl based magnesium alloy included: 6.5 g Al, 0.8 g Y, 0.5 g Mn, and 92.2 g Mg.

[0179] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0180] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0181] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0182] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0183] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Comparative Example 2

[0184] A MgAl based magnesium alloy included: 9.6 g Al, 0.8 g Y, 0.5 g Mn, and 89.1 g Mg.

[0185] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0186] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0187] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0188] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0189] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Comparative Example 3

[0190] A MgAl based magnesium alloy included: 7 g Al, 0.5 g Y, 0.5 g Mn, and 92.0 g Mg.

[0191] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0192] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0193] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0194] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0195] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Comparative Example 4

[0196] A MgAl based magnesium alloy included: 7 g Al, 2.3 g Y, 0.5 g Mn, and 90.2 g Mg.

[0197] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0198] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0199] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0200] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0201] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

Comparative Example 5

[0202] A MgAl based magnesium alloy included: 7 g Al, 0.8 g Y, and 92.2 g Mg.

[0203] The MgAl based magnesium alloy was obtained by the following preparation method specifically including: [0204] S101, an Al source, a Y source, a Mn source, and a Mg source were mixed thoroughly and smelted into a liquid mixed metal; [0205] S102, the liquid mixed metal was cast into a bar through a semi-continuous casting process; [0206] S103, the bar was heat-treated at 400 C. for a treatment duration of 8 h; and [0207] S104, the heat-treated bar was back-extruded at a speed of 12 mm/s and an extrusion temperature of 300 C. in an extrusion ratio of 49:1 to obtain the magnesium alloy tube.

TABLE-US-00001 TABLE 1 Performance parameters of MgAl based magnesium alloys of Examples 1-20 and Comparative Examples 1-5 Welding Yield Tensile strength strength strength Elongation loss Example (Mpa) (Mpa) (%) rate (%) Example 1 182 306 18.2 4.7 Example 2 191 319 16.9 5 Example 3 197 322 15.5 5.3 Example 4 202 320 15.2 5.4 Example 5 220 325 15 5.8 Example 6 219 325 16.3 4.8 Example 7 221 329 17.6 4.6 Example 8 224 326 19.6 5.3 Example 9 225 328 18.8 4.9 Example 10 226 325 19.2 4.5 Example 11 227 329 17.4 4.3 Example 12 223 324 19.5 4.6 Example 13 227 328 19.7 4.2 Example 14 230 330 20.1 4.1 Example 15 228 333 20.3 3.8 Example 16 232 338 20.8 3.6 Example 17 230 340 21.6 3.5 Example 18 230 334 19.1 4.6 Example 19 235 342 20 3.7 Example 20 231 339 19.8 4.2 Example 21 218 326 18.2 5.6 Example 22 220 316 16.9 5 Example 23 230 327 19 3.5 Comparative 165 287 15.2 4.9 Example 1 Comparative 226 340 12.7 7.3 Example 2 Comparative 173 294 13.9 5.8 Example 3 Comparative 185 312 12.8 5.3 Example 4 Comparative 179 289 14.3 6.2 Example 5

[0208] It can be seen from Table 1 that the yield strengths of the magnesium alloy tubes of Examples 1-23 can all reach 182 MPa or greater, and the yield strength of the magnesium alloy tube of Example 19 reached 235 MPa; the tensile strengths of them can all reach 306 MPa or greater, and the tensile strength of the magnesium alloy tube of Example 19 reached 342 Mpa; the elongations of them were all greater than 15%, and the elongation of the magnesium alloy tube of Example 17 reached 21.6%; and the welding loss rates of the magnesium alloy tubes of Examples 1-23 were all less than 6%, and the welding loss rates of the magnesium alloy tubes of Examples 15-17, Examples 19-20, and Example 23 were less than or equal to 4%, and can be as low as 3.5%.

[0209] Comparing Example 1 with Comparative Examples 1 and 2, the magnesium alloy in Comparative Example 1, because of the low content of Al added, has low yield strength and tensile strength, which are as low as 165 Mpa and 287 Mpa respectively, and an increased welding loss rate; and the magnesium alloy in Comparative Example 2, because of the excessively high content of Al added, has deteriorated plasticity, and an elongation decreased to 12.7%, and meanwhile, the welding loss rate increases significantly to 7.3%.

[0210] Comparing Example 1 with Comparative Examples 3 and 4, the magnesium alloy in Comparative Example 3, because of the low content of RE added, has low yield strength and tensile strength, poor plasticity, and an elongation of only 13.9%, and meanwhile, the welding loss rate increases; and for the magnesium alloy in Comparative Example 4, in which the content of RE added is too high, although the yield strength and tensile strength of the magnesium alloy are improved, the plasticity is significantly deteriorated, the elongation is only 12.8%, and the welding loss rate also increases.

[0211] Comparing Example 1 with Comparative Example 5, in Comparative Example 5, since Mn was not added, the overall performance of the magnesium alloy decreases, where the elongation is significantly reduced, and the welding loss rate is significantly increased to over 6%.

[0212] The MgAl based magnesium alloy of the present disclosure can be applied to the fields of vehicle equipment and medical equipment. For example, the MgAl based magnesium alloy is formed into a bar, and a plurality of magnesium alloy bars can be used, after welded, as a load-bearing member or support member for equipment such as a wheelchair, a stretcher, a bicycle, a mountain bike. The MgAl based magnesium alloy can reduce the weight of the equipment above while ensuring the strength and stability of the equipment above.