CN-121992259-A - Mn-containing ultra-light high-strength and high-toughness weak-texture magnesium-lithium alloy sheet and preparation method thereof

Abstract

The invention discloses an Mn-containing ultra-light high-strength and high-toughness weak-texture magnesium-lithium alloy sheet and a preparation method thereof, and belongs to the technical field of metal materials. The preparation method comprises the steps of preparing materials (comprising at least one of pure magnesium ingot, pure zinc ingot, magnesium-lithium intermediate alloy, magnesium-calcium intermediate alloy and magnesium-erbium/magnesium-manganese intermediate alloy), smelting under the protection of argon, casting and cooling at 720-750 ℃, wire cutting to obtain cast ingots, preheating and extruding the cast ingots at 200-300 ℃ to form plate blanks, and rolling at 25-200 ℃ in a small pass (2-4 passes) and large deformation. The novel short-range high-efficiency deformation process of adding light Ca element, grain refined Mn element or rare earth Er element, carrying out extrusion pre-deformation and carrying out on-line heating rolling with few passes and large deformation is utilized to improve the comprehensive mechanical property of the alloy, weaken the basal plane texture, improve the room temperature formability, realize the unification of ultra-light, high strength and toughness and high formability, simplify the process, realize low cost and high efficiency, and be suitable for the fields of aerospace, 3C electronics and the like.

Inventors

• YANG YAN
• PENG XIAODONG
• PAN FUSHENG
• LIU WEIHAO
• LI SHUSHAN
• Chi Tianfu
• WANG YIXUAN
• PEI DI
• YUAN XINYI
• GAO YUYANG
• JIANG BIN

Assignees

• 重庆大学
• 重庆新型储能材料与装备研究院

Dates

Publication Date

20260508

Application Date

20260204

Claims (9)

1. 1. The preparation method of the Mn-containing ultra-light high-strength and weak-strength textured magnesium-lithium alloy sheet is characterized by comprising the following steps of: s1, preparing materials, namely preparing a pure magnesium ingot, a pure zinc ingot, a magnesium-lithium intermediate alloy, a magnesium-calcium intermediate alloy and at least one of a magnesium-erbium intermediate alloy and a magnesium-manganese intermediate alloy; s2, smelting, namely smelting raw materials under the protection of argon to obtain an alloy melt; s3, casting, namely preserving heat of the melt at 720-750 ℃, deslagging, casting into a die, cooling, and performing linear cutting to obtain an ingot; S4, extrusion pre-deformation, namely preheating an ingot to 200-300 ℃, extruding into a plate blank at the extrusion ratio of 20-30:1 and the extrusion speed of 0.1-2mm/S and the temperature of 200-300 ℃, and air-cooling to room temperature; S5, performing online heating rolling, namely performing small-pass large-deformation rolling on the plate blank at 25-200 ℃ for 2-4 times, wherein the single-pass rolling reduction is 15-25%, and the total rolling reduction is 80-90%, so as to obtain the target thin plate.
2. 2. The method for preparing the Mn-containing ultra-light high-strength and weak-texture magnesium-lithium alloy sheet according to claim 1, wherein in the step S4, the preheating temperature is 210-260 ℃ and the preheating time is 1-2h.
3. 3. The method for preparing the Mn-containing ultra-light high-strength and weak-texture magnesium-lithium alloy sheet according to claim 1, wherein in the step S4, the extrusion ratio is (24-28): 1, the extrusion speed is 0.1-1mm/S, and the extrusion temperature is 210-260 ℃.
4. 4. The method for preparing the Mn-containing ultra-light high-strength and weak-texture magnesium-lithium alloy sheet according to claim 1, wherein in the step S5, the temperature of on-line heating and rolling is 60-150 ℃.
5. 5. A Mn-containing ultra-light high-strength and low-strength textured magnesium-lithium alloy sheet is characterized in that the magnesium-lithium alloy sheet is prepared by the preparation method of any one of claims 1-4.
6. 6. The Mn-containing ultra-light high-strength and weak-texture magnesium-lithium alloy sheet according to claim 5, wherein the chemical element composition of the magnesium-lithium alloy sheet comprises, by mass fraction, 5-13wt.% of Li, 0.1-4wt.% of Zn, 0.1-3wt.% of Ca, 0-3wt.% of Er, 0-3wt.% of Mn, and the balance of magnesium and unavoidable impurities, wherein the total content of the impurities is less than or equal to 0.3%, and the content of Er and Mn is not equal to 0.
7. 7. The Mn-containing ultra-light high-strength and weak-texture magnesium-lithium alloy sheet according to claim 6, wherein the chemical element composition of the magnesium-lithium alloy sheet comprises, by mass fraction, 6-12wt.% of Li, 1-3wt.% of Zn, 0.1-2wt.% of Ca, 0-2wt.% of Er, 0-2wt.% of Mn, and the balance of magnesium and unavoidable impurities, wherein the total content of the impurities is less than or equal to 0.3%, and the content of Er and Mn is not equal to 0.
8. 8. The Mn-containing ultra-light high-strength and weak-texture magnesium-lithium alloy sheet according to claim 5, wherein the thickness of the magnesium-lithium alloy sheet is 0.1-0.4mm.
9. 9. The Mn-containing ultra-light high-strength and weak-texture magnesium-lithium alloy sheet according to claim 5, wherein the magnesium-lithium alloy sheet has a yield strength of 200-260MPa, a tensile strength of 224-295MPa, an elongation of 8-26%, a density of 1.489-1.546g/cm 3 and a cylinder drawing depth of 9.1-13.6mm.

Description

Mn-containing ultra-light high-strength and high-toughness weak-texture magnesium-lithium alloy sheet and preparation method thereof Technical Field The invention relates to the technical field of metal materials, in particular to an Mn-containing ultra-light high-strength and high-toughness weak-texture magnesium-lithium alloy sheet and a preparation method thereof. Background The magnesium alloy serving as the lightest metal structural material has a series of advantages of high specific strength, high specific rigidity, good damping and shock absorption performance, excellent electromagnetic shielding performance, easy recovery and the like, and has great application potential in the fields of aerospace, national defense and military industry, 3C electronic products, transportation and the like. However, the conventional magnesium alloy (such as AZ31, ZK60, etc.) has a small number of independent sliding systems at room temperature due to its close-packed hexagonal crystal structure, resulting in poor plastic working ability and low formability, which severely restricts its large-scale commercial application, especially in the field requiring complex-shape sheet press forming. The density of the magnesium-lithium alloy is the smallest in the existing alloy system, and the density of the added metal lithium is only 0.543g/cm 3, so that the density of the magnesium-lithium alloy is reduced along with the increase of the adding amount of lithium element, the density of the magnesium-lithium alloy is only 2/3-3/4 of that of the general magnesium alloy, and the density of the magnesium-lithium alloy is 1/3-1/2 lighter than that of most aluminum alloys, and therefore, the magnesium-lithium alloy is also called as an ultra-light alloy. When the lithium content exceeds about 5.7wt.%, the alloy crystal structure is changed from a close-packed six-way body-centered cubic structure, and the body-centered cubic structure has more slip systems, so that the room-temperature plasticity, toughness and cold forming capability of the magnesium-lithium alloy are obviously improved, and the possibility is provided for preparing the ultra-light and high-formability magnesium-lithium alloy sheet. However, magnesium-lithium alloy has the defects of poor thermal stability, low absolute strength, insufficient formability and the like, so that large-scale industrial application is not realized. Alloying is one of effective methods for improving the mechanical properties of the magnesium-lithium alloy material. Zn and Ca are main alloying elements in the magnesium-lithium alloy, and alloy systems such as Mg-Li-Zn or Mg-Li-Zn-Ca are formed at present, but the solid solubility of the elements in the magnesium-lithium alloy is limited, the improvement of alloy strength is limited, the stability of the mechanical properties of the alloy is easily caused to be poor, and the preparation of the ultra-light high-performance magnesium-lithium alloy sheet is not facilitated. In addition, in the preparation research of magnesium-lithium alloy thin plates at present, a process route of repeated hot rolling, intermediate annealing and post-rolling annealing for multiple passes is mostly adopted, the process has the problems of long path, high cost, low production efficiency and the like, and the structure and the performance of the plate are difficult to keep uniform and stable in the processes of multiple heating and rolling, so that anisotropy and stronger texture are easy to generate, and the forming limit of the thin plates is further reduced. Therefore, development of a novel alloying design and a short-range efficient preparation process are needed to realize the unification of ultra-light, high strength and toughness and high formability of the magnesium-lithium alloy sheet. Disclosure of Invention The invention aims to provide an Mn-containing ultra-light high-strength and weak-texture magnesium-lithium alloy sheet and a preparation method thereof, wherein the Mn element refines crystal grains, the Ca element weakens basal plane texture, and then the sheet is deformed into a sheet blank through extrusion and pre-deformation, and a novel short-range efficient deformation process of on-line heating rolling with few passes and large deformation is adopted to improve the strength and plasticity of the alloy, so that the ultra-light high-strength high-toughness weak texture magnesium-lithium alloy sheet is prepared. The method realizes perfect combination of ultra-light, high strength and toughness and high formability of the magnesium-lithium alloy sheet, simplifies the process flow, improves the production efficiency, improves the product quality stability and greatly reduces the production cost, thereby solving the problems in the background technology. In order to achieve the above purpose, the invention provides a preparation method of an Mn-containing ultra-light high-strength and high-toughness weak texture magnesium-lithium alloy sh