Mg-Al magnesium alloy and its pipe material manufacturing method, and its application

Abstract

The present invention relates to an Mg-Al magnesium alloy, its manufacturing method, and its application, and belongs to the field of alloy material technology. This magnesium alloy contains, in weight percent, the composition Al: 7.0-8.6%, RE: 0.8-2.0%, Mn: 0.2-0.8%, and the balance is Mg, and the elongation of this Mg-Al magnesium alloy is 15-22%. The manufacturing method of Mg-Al magnesium alloy pipe material includes the steps of mixing and melting an Al source, an RE source, an Mn source, and an Mg source to form a liquid mixed metal, semi-continuously casting the liquid mixed metal into a rod material, subjecting the rod material to homogenization heat treatment at 360-400°C for 6-10h, and extruding the heat-treated rod material to obtain a magnesium alloy pipe material. The Mg-Al magnesium alloy of the present invention has a high elongation, and the elongation of the formed pipe is 15-22%, and can withstand large plastic deformation. In addition, this Mg-Al magnesium alloy has excellent welding performance, with a welding strength loss rate of less than 6%, which greatly reduces the strength loss of magnesium alloy shaped products after welding and ensures the strength of magnesium alloy shaped products after welding. This Mg-Al magnesium alloy is used in the fields of vehicle equipment and medical equipment.

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This disclosure claims priority to a Chinese patent application bearing application number CN 202110040804.4, entitled "Mg-Al-based magnesium alloy and its manufacturing method for pipe material, and application thereof," filed with the China Patent Office on January 13, 2021, the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] The present invention relates to an Mg-Al based magnesium alloy, a method for manufacturing a magnesium alloy pipe material, and applications of the Mg-Al based magnesium alloy, and belongs to the field of alloy material technology. [Background technology]

[0003] To date, magnesium alloys are the lightest metallic structural materials, with densities equivalent to only two-thirds that of aluminum and one-quarter that of steel, yet possessing high specific strength and rigidity. Furthermore, magnesium alloys have many excellent properties, such as good damping properties, machinability, thermal conductivity, and ease of recovery and recycling, and their application fields are expanding.

[0004] Magnesium alloys mainly include Mg-Al and Mg-Zn-Zr magnesium alloys, and Mg-Al magnesium alloys are widely used due to their lower production cost and easier manufacturing method. However, conventional Mg-Al alloys have poor elongation and are prone to fracture when subjected to impact deformation due to external force or cyclic loading. In addition, magnesium alloys are generally connected to each other by welding when used in applications, but conventional Mg-Al alloys have a large loss of weld strength after welding, which not only results in a large waste of resources but also affects the robustness of the weld and the aesthetic appearance. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide an Mg-Al-based magnesium alloy that has high elongation and low welding strength loss rate, thereby overcoming the problems of conventional Mg-Al-based magnesium alloys, and to provide a method for manufacturing this Mg-Al-based magnesium alloy pipe material. We also provide applications of this Mg-Al magnesium alloy in the fields of vehicle equipment and medical equipment. [Means for solving the problem]

[0006] The Mg-Al-based magnesium alloy according to the present invention contains, in weight percent, the composition Al: 7.0-8.6%, RE: 0.8-2.0%, Mn: 0.2-0.8%, and the remainder Mg, and the elongation of this Mg-Al-based magnesium alloy is 15-22%.

[0007] Optionally, the elongation of the Mg—Al-based magnesium alloy is 17 to 21.6%.

[0008] Optionally, the Mg—Al-based magnesium alloy has a weld strength loss rate of less than 6%.

[0009] Optionally, the Mg—Al-based magnesium alloy has a yield strength of 182 to 235 MPa and a tensile strength of 306 to 342 MPa.

[0010] In this Mg—Al-based magnesium alloy, the Al content (wt %) is preferably 7.0 to 8.2%, the RE content (wt %) is preferably 1.1 to 2.0%, and the Mn content (wt %) is preferably 0.4 to 0.8%. The Mg-Al based magnesium alloy within the above parameter range can achieve a lower weld strength loss rate (less than 5.5%), a higher elongation rate, and a higher strength.

[0011] In this Mg-Al-based magnesium alloy, it is more preferable that the Al content (wt%) is 7.8 to 8.2%, the RE content (wt%) is 1.3 to 1.9%, the Mn content (wt%) is 0.5 to 0.8%, and the Y content (wt%) in the RE is 0.8 to 1.6%, and the Ce content (wt%) is 0 to 0.8%. In this case, the elongation of the resulting Mg-Al magnesium alloy is 17.4 to 21.6%, the welding strength loss rate is less than 5%, and the yield strength reaches 220 to 235 MPa and the tensile strength reaches 320 to 342 MPa.

[0012] It is even more preferable that the Al content (wt%) in this Mg-Al-based magnesium alloy is 7.8 to 8.2%, the content (wt%) in RE is 1.5 to 1.9%, the Mn content (wt%) is 0.5 to 0.8%, and the Y content (wt%) in RE is 0.8%, and the Ce content (wt%) is 0.5 to 0.8%. In this case, the welding strength loss rate of the resulting Mg—Al-based magnesium alloy is 4.3% or less.

[0013] Optionally, in the magnesium alloy, RE includes at least one of La, Ce, Nd, Y, Gd, Ho, Dy, and Er, and RE mainly includes Y and Ce, with other rare earth elements being present in trace amounts.

[0014] The method for producing an Mg—Al-based magnesium alloy pipe material according to the present invention includes the following steps.

[0015] a step of mixing and melting an Al source, an RE source, an Mn source, and an Mg source to form a liquid mixed metal according to the weight percent of the elements: Al: 7.0 to 8.6%, RE: 0.8 to 2.0%, Mn: 0.2 to 0.8%, and the remainder: Mg;

[0016] semi-continuously casting the liquid mixed metal into a bar;

[0017] A step of subjecting the bar material to homogenization heat treatment at 360 to 400°C for 6 to 10 hours;

[0018] and extruding the heat-treated rod material to obtain an Mg—Al-based magnesium alloy pipe material.

[0019] The application of the Mg-Al based magnesium alloy described in this invention is to use this Mg-Al based magnesium alloy in the fields of vehicle equipment and medical equipment. [Effects of the Invention]

[0020] Compared with the prior art, the Mg-Al magnesium alloy of the present invention has the advantage of having a high elongation rate, with the elongation rate of the formed pipe being 15 to 22%, and being able to withstand large plastic deformation. Furthermore, the welding strength loss rate of this Mg-Al-based magnesium alloy is low at less than 6%, which significantly reduces the loss of strength after welding of magnesium alloy shaped products and ensures the strength of the magnesium alloy shaped products after welding. Furthermore, the Mg—Al-based magnesium alloy of the present invention has high strength, with a yield strength of 182 to 232 MPa and a tensile strength of 306 to 340 MPa. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a flowchart of a manufacturing process for an Mg—Al-based magnesium alloy according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, the present invention to This will be further explained with reference to the drawings and examples.

[0023] The Mg—Al-based magnesium alloy of the present invention contains, in weight percent, 7.0 to 8.6% Al, 0.8 to 2.0% RE, 0.2 to 0.8% Mn, and the remainder being Mg.

[0024] Specifically, the Mg-Al-based magnesium alloy of the present invention improves the plasticity and strength of the magnesium alloy by adding RE (rare earth elements) and Mn to the Mg-Al-based alloy, and reduces the welding strength loss rate of the alloy.

[0025] The addition of Mn can remove the impurity element Fe introduced during semi-continuous casting, which is beneficial to the weldability and mechanical properties, and reduces the rate of weld strength loss. Furthermore, Mn does not form compounds in magnesium, but rather acts as a heterogeneous nucleation site, thereby refining the crystal grains. When extruded into a pipe, this promotes dynamic recrystallization, refining the crystal grains, weakening the structure, and improving strength and plasticity.

[0026] The addition of RE can refine the grain size of magnesium alloys, improve the morphology of the β strengthening phase of magnesium alloys, and increase the strength and plasticity of magnesium alloys. The strength of a magnesium alloy can be expressed in terms of yield strength and tensile strength. After the Mg-Al-based magnesium alloy provided by the present invention is formed into a pipe material, the yield strength of the pipe material is in the range of 182 to 235 MPa, preferably 220 to 235 MPa. The tensile strength of this Mg—Al-based magnesium alloy pipe material is in the range of 306 to 342 MPa, preferably 320 to 340 MPa. The elongation is directly related to the plasticity of the magnesium alloy. After the Mg-Al-based magnesium alloy provided in the present invention is formed into a pipe material, the elongation of the pipe material can reach 15-22%, and preferably the elongation of this Mg-Al-based magnesium alloy pipe material is 17-21.6%. The high elongation allows the magnesium alloy to withstand large plastic deformation, thereby expanding the application range of the magnesium alloy.

[0027] The welding strength loss rate is the rate of strength loss of a welded sample relative to an original formed material sample after welding of a magnesium alloy formed material. The weld strength loss rate of the Mg-Al-based magnesium alloy provided by the present invention is less than 6%, preferably less than 5%, and more preferably less than 4.3%. In the Mg-Al-based magnesium alloys provided in the examples of the present invention, the addition of RE elements forms an Al-RE high-temperature stable phase during high-temperature welding, and this high-temperature stable phase adheres to grain boundaries, inhibiting the growth of magnesium alloy crystal grains during welding. In addition, the RE elements significantly refine the size of the β strengthening phase in the magnesium alloy and prevent the growth of the β strengthening phase during high-temperature welding, thereby reducing the loss of strength after welding of the magnesium alloy formed material and ensuring the strength of the magnesium alloy formed material after welding.

[0028] Optionally, the weight percent range of Al in the Mg-Al-based magnesium alloy of the present invention is 7.0-8.6%, preferably the weight percent range of Al in the Mg-Al-based magnesium alloy is 7.0-8.2%, more preferably the weight percent range of Al is 7.8-8.2%.

[0029] Specifically, when the weight percentage of Al in this Mg-Al-based magnesium alloy is controlled within a certain range, the combination of Al element and Mg element has the effect of strengthening the second phase, and in the magnesium alloy forming process, a β strengthening phase with an optimal state (appropriate volume fraction, shape, and size) is obtained, thereby improving the strength of the magnesium alloy. Furthermore, the Al element in the solid solution portion in the magnesium matrix can play a role in solid solution strengthening and improving plasticity. If the weight percentage of Al in this Mg-Al magnesium alloy is too high, for example, exceeding 8.6%, a coarse eutectic β phase precipitates, which weakens the interfacial bonding ability between the precipitated phase and the matrix after welding, making it easier for micropores to form at the interface between the matrix and the β phase, increasing the rate of weld strength loss, while the coarse β phase causes stress concentration during service, leading to early plastic collapse and reduced elongation. On the other hand, if the weight percentage of Al in the magnesium alloy is too low, for example, less than 7%, the amount of Al element in the grains decreases, which is disadvantageous for improving plasticity, and the degree of crystal grain refinement with a small number of precipitated phases decreases, making it difficult for the second phase strengthening effect to work, which is disadvantageous for improving the strength of the magnesium alloy. Additionally, alloys with fewer precipitated phases will experience more pronounced grain growth after welding, resulting in an increased rate of weld strength loss.

[0030] Optionally, the weight % range of RE in the Mg-Al-based magnesium alloy of the present invention is 0.8-2.0%, preferably, the weight % range of RE in the Mg-Al-based magnesium alloy is 1.1-2.0%, more preferably, the weight % range of RE is 1.3-1.9%. Specifically, when RE is added to this Mg-Al magnesium alloy, the RE element has a unique electron configuration structure and chemical characteristics, and adding an appropriate amount of rare earth element to the magnesium alloy makes it possible to strengthen the interatomic bonding force, reduce the diffusion rate of magnesium atoms, increase the recrystallization temperature of the magnesium alloy, and moderate the recrystallization growth rate, thereby significantly improving the formability and corrosion resistance. In addition, RE is generally distributed at grain boundaries, which can refine the grain size of magnesium alloys and improve the harmony between each grain of the magnesium alloy. Furthermore, RE can form a thermally stable β strengthening phase during the forming process of magnesium alloys, thereby improving the strength and plasticity of the magnesium alloys.

[0031] The RE may include at least one of La, Ce, Nd, Y, Gd, Ho, Dy, and Er. Specifically, the RE elements in the Mg-Al-based magnesium alloy of the present invention are mainly Y and Ce, with the weight percentage range of Y being 0.8 to 1.6% and the weight percentage range of Ce being 0 to 0.8%.

[0032] As shown in FIG. 1, the present invention provides a method for producing an Mg—Al-based magnesium alloy, which includes the following steps:

[0033] S101: According to the element contents by weight percentage of Al: 7.0 to 8.6%, RE: 0.8 to 2.0%, Mn: 0.2 to 0.8%, and the remainder: Mg, an Al source, an RE source, an Mn source, and an Mg source are mixed and melted, and then a liquid mixed metal is formed.

[0034] S102: Cast the liquid mixed metal into ingots.

[0035] S103: The ingot is subjected to a homogenizing heat treatment at a first temperature.

[0036] S104: The heat-treated ingot is extruded to obtain the Mg—Al-based magnesium alloy of the present invention.

[0037] Specifically, the casting process of S102 can be realized by a semi-continuous casting process. The semi-continuous process allows for rapid water cooling, resulting in small grain sizes, and the fine grains can simultaneously improve the alloy strength and elongation. In S103, the first temperature ranges from 360 to 400°C, and the heat treatment time is from 6 to 10 hours. By adopting the heat treatment process before extrusion, the content of Al element in the matrix can be increased, the slip system can be increased, and the elongation rate of the alloy can be improved.

[0038] When producing a Mg—Al-based magnesium alloy pipe material, in step S102, the ingot is cast into a rod, that is, the liquid mixed metal is cast into a rod. In step S104, the heat-treated bar is reverse extruded to obtain an Mg—Al-based magnesium alloy pipe material. The process parameters of reverse extrusion include extrusion temperature, extrusion ratio, and extrusion speed, of which the extrusion temperature range is 280-330°C, the extrusion ratio is 49:1, and the extrusion speed range is 8-15 mm / s.

[0039] Hereinafter, the magnesium alloy provided by the present invention will be described in detail with specific examples and comparative examples, taking the production of an Mg-Al based magnesium alloy pipe material as an example. The magnesium alloy pipe material obtained by the manufacturing method of the present invention has a large elongation rate, can withstand large plastic deformation, and has a low welding strength loss rate, and these properties improve the range of applications of the magnesium alloy pipe material. In addition, this Mg-Al based magnesium alloy has high yield strength and tensile strength.

[0040] Example 1

[0041] The Mg-Al magnesium alloy contains 7g of Al, 0.8g of Y, 0.5g of Mn, and 91.7g of Mg.

[0042] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0043] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0044] S102: The liquid mixed metal is cast into bar stock by a semi-continuous casting process.

[0045] S103: The bar was heat treated at 400°C for 8 hours.

[0046] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0047] <Example 2>

[0048] The Mg-Al magnesium alloy contains 7.4g of Al, 0.8g of Y, 0.5g of Mn, and 91.3g of Mg.

[0049] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0050] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0051] S102: The liquid mixed metal is cast into bar stock by a semi-continuous casting process.

[0052] S103: The bar was heat treated at 360°C for 10 hours.

[0053] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 8 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 280°C and the extrusion ratio was 49:1.

[0054] Example 3

[0055] The Mg-Al magnesium alloy contains 7.8g of Al, 0.8g of Y, 0.5g of Mn, and 91.9g of Mg.

[0056] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0057] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0058] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0059] S103: The bar was heat treated at 400°C for 8 hours.

[0060] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0061] Example 4

[0062] The Mg-Al magnesium alloy contains 8.2g of Al, 0.8g of Y, 0.5g of Mn, and 90.5g of Mg.

[0063] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0064] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0065] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0066] S103: The bar was heat treated at 380°C for 6 hours.

[0067] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 10 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 330°C and the extrusion ratio was 49:1.

[0068] <Example 5>

[0069] The Mg-Al magnesium alloy contains 8.6g of Al, 0.8g of Y, 0.5g of Mn, and 90.1g of Mg.

[0070] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0071] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0072] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0073] S103: The bar was heat treated at 400°C for 8 hours.

[0074] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0075] Example 6

[0076] The Mg-Al magnesium alloy contains 7.8g of Al, 1.2g of Y, 0.5g of Mn, and 90.5g of Mg.

[0077] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0078] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0079] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0080] S103: The bar was heat treated at 400°C for 8 hours.

[0081] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0082] Example 7

[0083] The Mg-Al magnesium alloy contains 7.8g of Al, 1.6g of Y, 0.5g of Mn, and 90.1g of Mg.

[0084] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0085] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0086] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0087] S103: The bar was heat treated at 400°C for 8 hours.

[0088] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0089] Example 8

[0090] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.3g (RE: 1.1%), Mn: 0.5g, and Mg: 90.6g.

[0091] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0092] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0093] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0094] S103: The bar was heat treated at 400°C for 8 hours.

[0095] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0096] Example 9

[0097] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 1.2g, Ce: 0.3g (RE: 1.5%), Mn: 0.5g, and Mg: 90.2g.

[0098] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0099] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0100] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0101] S103: The bar was heat treated at 400°C for 8 hours.

[0102] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0103] Example 10

[0104] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.5g (RE: 1.3%), Mn: 0.5g, and Mg: 90.4g.

[0105] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0106] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0107] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0108] S103: The bar was heat treated at 400°C for 8 hours.

[0109] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0110] Example 11

[0111] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.8g (RE: 1.6%), Mn: 0.5g, and Mg: 90.1g.

[0112] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0113] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0114] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0115] S103: The bar was heat treated at 400°C for 8 hours.

[0116] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0117] Example 12

[0118] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.5g, La: 0.1g (RE: 1.4%), Mn: 0.5g, and Mg: 90.3g.

[0119] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0120] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0121] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0122] S103: The bar was heat treated at 400°C for 8 hours.

[0123] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0124] Example 13

[0125] The Mg-Al magnesium alloy contains 7.8g of Al, 0.8g of Y, 0.5g of Ce, 0.1g of La, 0.1g of Nd (RE: 1.5%), 0.5g of Mn, and 90.2g of Mg.

[0126] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0127] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0128] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0129] S103: The bar was heat treated at 400°C for 8 hours.

[0130] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0131] Example 14

[0132] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.5g, La: 0.1g, Nd: 0.1g, Gd: 0.1g (RE: 1.6%), Mn: 0.5g, and Mg: 90.1g.

[0133] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0134] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0135] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0136] S103: The bar was heat treated at 400°C for 8 hours.

[0137] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0138] Example 15

[0139] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.5g, La: 0.1g, Nd: 0.1g, Gd: 0.1g, Ho: 0.1g (RE: 1.7%), Mn: 0.5g, and Mg: 90.1g.

[0140] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0141] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0142] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0143] S103: The bar was heat treated at 400°C for 8 hours.

[0144] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0145] Example 16

[0146] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.5g, La: 0.1g, Nd: 0.1g, Gd: 0.1g, Ho: 0.1g, Dy: 0.1g (RE: 1.8%), Mn: 0.5g, and Mg: 90.0g.

[0147] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0148] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0149] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0150] S103: The bar was heat treated at 400°C for 8 hours.

[0151] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0152] Example 17

[0153] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.5g, La: 0.1g, Nd: 0.1g, Gd: 0.1g, Ho: 0.1g, Er: 0.1g (RE: 1.9%), Mn: 0.5g, and Mg: 89.9g.

[0154] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0155] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0156] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0157] S103: The bar was heat treated at 400°C for 8 hours.

[0158] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0159] Example 18

[0160] The Mg-Al-based magnesium alloy contains Al: 8.0g, Y: 0.8g, Ce: 0.5g (RE: 1.3%), Mn: 0.5g, and Mg: 90.4g.

[0161] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0162] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0163] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0164] S103: The bar was heat treated at 400°C for 8 hours.

[0165] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0166] Example 19

[0167] The Mg-Al magnesium alloy contains Al: 8.0g, Y: 0.8g, Ce: 0.5g, La: 0.1g, Nd: 0.1g, Gd: 0.1g, Ho: 0.1g, Er: 0.1g (RE: 1.9%), Mn: 0.5g, and Mg: 89.6g.

[0168] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0169] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0170] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0171] S103: The bar was heat treated at 400°C for 8 hours.

[0172] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0173] Example 20

[0174] The Mg-Al magnesium alloy contains Al: 8.2g, Y: 0.8g, Ce: 0.5g, La: 0.1g, Nd: 0.1g, Gd: 0.1g (RE: 1.6%), Mn: 0.5g, and Mg: 89.7g.

[0175] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0176] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0177] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0178] S103: The bar was heat treated at 400°C for 8 hours.

[0179] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0180] <Example 21>

[0181] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.5g (RE: 1.3%), Mn: 0.2g, and Mg: 90.7g.

[0182] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0183] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0184] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0185] S103: The bar was heat treated at 400°C for 8 hours.

[0186] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0187] <Example 22>

[0188] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.5g (RE: 1.3%), Mn: 0.4g, and Mg: 90.5g.

[0189] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0190] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0191] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0192] S103: The bar was heat treated at 400°C for 8 hours.

[0193] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0194] Example 23

[0195] The Mg-Al magnesium alloy contains Al: 7.8g, Y: 0.8g, Ce: 0.5g (RE: 1.3%), Mn: 0.8g, and Mg: 90.1g.

[0196] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0197] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0198] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0199] S103: The bar was heat treated at 400°C for 8 hours.

[0200] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0201] <Comparative Example 1>

[0202] The Mg-Al magnesium alloy contains Al: 6.5g, Y: 0.8g, Mn: 0.5g, and Mg: 92.2g.

[0203] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0204] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0205] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0206] S103: The bar was heat treated at 400°C for 8 hours.

[0207] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0208] <Comparative Example 2>

[0209] The Mg-Al magnesium alloy contains Al: 9.6g, Y: 0.8g, Mn: 0.5g, and Mg: 89.1g.

[0210] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0211] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0212] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0213] S103: The bar was heat treated at 400°C for 8 hours.

[0214] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0215] <Comparative Example 3>

[0216] The Mg-Al magnesium alloy contains 7g of Al, 0.5g of Y, 0.5g of Mn, and 92.0g of Mg.

[0217] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0218] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0219] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0220] S103: The bar was heat treated at 400°C for 8 hours.

[0221] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0222] <Comparative Example 4>

[0223] The Mg-Al magnesium alloy contains 7g of Al, 2.3g of Y, 0.5g of Mn, and 90.2g of Mg.

[0224] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0225] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed and melt-kneaded to form a liquid mixed metal.

[0226] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0227] S103: The bar was heat treated at 400°C for 8 hours.

[0228] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0229] <Comparative Example 5>

[0230] The Mg-Al magnesium alloy contains 7g of Al, 0.8g of Y, and 92.2g of Mg.

[0231] Specifically, this Mg—Al-based magnesium alloy can be obtained by the following manufacturing method.

[0232] S101: An Al source, a Y source, a Mn source, and an Mg source are uniformly mixed, and the mixed raw materials are melted and kneaded to form a liquid mixed metal;

[0233] S102: Liquid mixed metal is cast into bars by semi-continuous casting technique.

[0234] S103: The bar was heat treated at 400°C for 8 hours.

[0235] S104: The heat-treated rod material was reverse-extruded at an extrusion speed of 12 mm / s to obtain a magnesium alloy pipe material. The extrusion temperature was 300°C and the extrusion ratio was 49:1.

[0236] Table 1 Performance parameters of Mg-Al based magnesium alloys of Examples 1 to 20 and magnesium alloys of Comparative Examples 1 to 5

[0237] JPEG0007727753000001.jpg168169

[0238] As can be seen from Table 1, the yield strength of the magnesium alloy pipe materials of Examples 1 to 23 is all 182 MPa or more, the yield strength of the magnesium alloy pipe material of Example 19 reaches 235 MPa, the tensile strength is all 306 MPa or more, the tensile strength of the magnesium alloy pipe material of Example 19 reaches 342 MPa, the elongation is all greater than 15%, the elongation of the magnesium alloy pipe material of Example 17 reaches 21.6%, the welding strength loss rate of the magnesium alloy pipe materials of Examples 1 to 23 is all less than 6%, and the welding strength loss rate of the magnesium alloy pipe materials of Examples 15 to 17, Examples 19 to 20 and Example 23 is 4% or less, and can be reduced to 3.5%.

[0239] Comparing Example 1 with Comparative Examples 1 and 2, in Comparative Example 1, the content of added Al is low, so the yield strength and tensile strength of the magnesium alloy are low at 165 MPa and 287 MPa, respectively, and the weld strength loss rate increases. In Comparative Example 2, the content of added Al was too high, which deteriorated the plasticity of the magnesium alloy, resulting in a decrease in elongation to 12.7% and a significant increase in weld strength loss rate to 7.3%.

[0240] Comparing Example 1 with Comparative Examples 3 and 4, in Comparative Example 3, the content of added RE was too low, so the yield strength and tensile strength of the magnesium alloy were low, and furthermore, the plasticity was poor, with the elongation being 13.9% and the weld strength loss rate increasing. In Comparative Example 4, the content of added RE was too high, and although the yield strength and tensile strength of the magnesium alloy were improved, the plasticity was significantly deteriorated, the elongation rate was only 12.8%, and the weld strength loss rate also increased.

[0241] Comparing Example 1 with Comparative Example 5, in Comparative Example 5, the addition of Mn reduced the overall performance of the magnesium alloy, with the elongation rate decreasing significantly and the weld strength loss rate increasing significantly to over 6%.

[0242] The Mg-Al-based magnesium alloy of the present invention can be applied to the fields of vehicle equipment and medical equipment. For example, the Mg-Al-based magnesium alloy can be formed into a rod, and a plurality of magnesium alloy rods can be welded together to form load-bearing or support members for equipment such as wheelchairs, stretchers, bicycles, and mountain bikes, thereby reducing the weight of such equipment and ensuring its strength and stability.

Claims

1. An Mg—Al-based magnesium alloy, The alloy contains, in weight percent, 7.0 to 8.6% Al, 0.8 to 2.0% RE (rare earth elements), 0.2 to 0.8% Mn, and the balance being Mg; The RE (rare earth element) includes at least one of La, Ce, Nd, Y, Gd, Ho, Dy, and Er, The Mg—Al-based magnesium alloy has an elongation of 15 to 22%.

2. In the Mg—Al-based magnesium alloy, the Al content (wt%) is 7.0 to 8.2%, The content (wt%) of RE (rare earth element) is 1.1 to 2.0%, 2. The Mg-Al magnesium alloy according to claim 1, wherein the Mn content (wt%) is 0.4 to 0.8%.

3. In the Mg—Al-based magnesium alloy, the Al content (wt%) is 7.8 to 8.2%, The content (wt%) of RE (rare earth element) is 1.3 to 1.9%, The Mn content (wt%) is 0.5 to 0.8%, The Mg-Al-based magnesium alloy according to claim 2, characterized in that the content (wt%) of Y in the RE (rare earth elements) is 0.8 to 1.6%, and the content (wt%) of Ce is 0 to 0.8%.

4. 2. The Mg—Al-based magnesium alloy according to claim 1, wherein the elongation of the Mg—Al-based magnesium alloy is 17 to 21.6%.

5. 2. The Mg—Al-based magnesium alloy according to claim 1, wherein the Mg—Al-based magnesium alloy has a yield strength of 182 to 235 MPa and a tensile strength of 306 to 342 MPa.

6. A method for producing an Mg—Al-based magnesium alloy pipe material, a step of mixing and melting an Al source, an RE (rare earth element) source, an Mn source, and an Mg source, the elements being, in weight percent, 7.0 to 8.6% Al, 0.8 to 2.0% RE (rare earth element), 0.2 to 0.8% Mn, and the balance being Mg, and the RE (rare earth element) includes at least one of La, Ce, Nd, Y, Gd, Ho, Dy, and Er, to form a liquid mixed metal; semi-continuously casting the liquid mixed metal into a bar; performing a homogenization heat treatment on the rod at 360 to 400 ° C. for 6 to 10 hours; and a step of reverse extruding the heat-treated rod material to obtain the Mg—Al-based magnesium alloy pipe material. The method for producing an Mg—Al based magnesium alloy pipe material is characterized in that the elongation of the Mg—Al based magnesium alloy pipe material is 15 to 22%.

7. 6. An application of the Mg—Al-based magnesium alloy according to any one of claims 1 to 5 to be used in the field of vehicle equipment or medical equipment.

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