Search

CN-121976101-A - Medium-high temperature creep-resistant magnesium alloy and preparation method and application thereof

CN121976101ACN 121976101 ACN121976101 ACN 121976101ACN-121976101-A

Abstract

The invention provides a medium-high temperature creep-resistant magnesium alloy and a preparation method and application thereof, wherein the medium-high temperature creep-resistant magnesium alloy has a general formula of Mg- (9.0-15.0) A- (0.2-1.0) B- (0.5-2.0) Zn, wherein the element A is one or more of gadolinium, yttrium and dysprosium, and the element B is manganese and/or calcium according to mass percentage. The high-temperature creep-resistant magnesium alloy improves the creep resistance through multielement segregation. Under the combined action of specific alloy component design and a thermomechanical treatment process, the high-temperature creep-resistant magnesium alloy not only forms a kink zone interface with high stability, but also creates conditions for precipitation of nano phases in the subsequent high-temperature service process by element segregation, thereby realizing the effective inhibition of creep deformation in a multi-scale and whole process.

Inventors

  • ZHANG ZHIROU
  • Xian Jingwei
  • WANG MINGLIANG
  • Xin Tongzheng
  • CAO ZHIQIANG
  • LI TINGJU
  • WANG TONGMIN
  • GUO ENYU
  • DU ZELONG
  • KANG HUIJUN
  • CHEN ZONGNING
  • LU YIPING
  • JIE JINCHUAN
  • ZHANG YUBO

Assignees

  • 大连理工大学

Dates

Publication Date
20260505
Application Date
20260120

Claims (10)

  1. 1. The medium-high temperature creep-resistant magnesium alloy is characterized by comprising the following general formula of Mg- (9.0-15.0) A- (0.2-1.0) B- (0.5-2.0) Zn according to mass percentage, wherein the element A is one or more of gadolinium, yttrium and dysprosium, and the element B is manganese and/or calcium.
  2. 2. The medium and high temperature creep resistant magnesium alloy according to claim 1, wherein at least one of the a elements exceeds 40 wt% of its solid solution limit.
  3. 3. The medium and high temperature creep resistant magnesium alloy according to claim 1, wherein gadolinium content exceeds 9.4 wt%, or yttrium content exceeds 5.08 wt%, or dysprosium content exceeds 10.23 wt%.
  4. 4. The medium-high temperature creep-resistant magnesium alloy according to claim 1, wherein the kink zone interface percentage of the medium-high temperature creep-resistant magnesium alloy is equal to or more than 70%, and the recrystallization volume percentage is equal to or less than 10%.
  5. 5. The medium and high temperature creep resistant magnesium alloy according to claim 4, wherein the a and B elements are biased on a kink zone, and the concentration of A, B elements on the kink zone is 1.5-5 times that of the in-crystal element.
  6. 6. A method for preparing the medium-high temperature creep-resistant magnesium alloy according to any one of claims 1 to 5, comprising the steps of: (1) Weighing the raw materials according to the general formula, under the protection of inert gas, completely melting a magnesium ingot at 650-730 ℃, heating to 750-800 ℃, sequentially adding an element A, an element B and an element Zn, refining for 20-40 min, and casting to obtain a magnesium alloy ingot; (2) Carrying out homogenizing annealing treatment on the magnesium alloy ingot, wherein the annealing treatment temperature is 450-540 ℃, and the annealing treatment time is 12-72 hours; (3) And carrying out hot extrusion on the magnesium alloy cast ingot subjected to the homogenization treatment to obtain the medium-high temperature creep-resistant magnesium alloy, wherein the hot extrusion temperature is 400-500 ℃, the hot extrusion ratio is 4:1-36:1, and the hot extrusion speed is 5-50 mm/min.
  7. 7. The method for preparing the medium-high temperature creep-resistant magnesium alloy according to claim 6, wherein after the step (1) is refined, standing molten metal, slagging off and cooling to 680-710 ℃, and casting the molten metal into a preheated copper mold to obtain an ingot.
  8. 8. The method for preparing a medium-high temperature creep-resistant magnesium alloy according to claim 6, wherein in the step (2), the homogenizing annealing treatment temperature is 480-525 ℃ and the annealing treatment time is 24-60 h.
  9. 9. The method for preparing a medium-high temperature creep-resistant magnesium alloy according to claim 6, wherein in the step (3), the hot extrusion temperature is 400-480 ℃, the hot extrusion ratio is 10:1-36:1, and the hot extrusion speed is 5-30 mm/min.
  10. 10. Use of the medium-high temperature creep-resistant magnesium alloy according to any one of claims 1-5 in aerospace, transportation, 3C electronics.

Description

Medium-high temperature creep-resistant magnesium alloy and preparation method and application thereof Technical Field The invention relates to a magnesium alloy technology, in particular to a medium-high temperature creep-resistant magnesium alloy and a preparation method and application thereof. Background The magnesium alloy as the lightest metal structural material has the outstanding advantages of low density, high specific strength, good damping and shock absorption performance, excellent electromagnetic shielding performance, easy recovery and the like, and has wide application prospect in the fields of aerospace, transportation, 3C electronics and the like. For the above-mentioned fields, the realization of weight saving of equipment is one of the key technical approaches to cope with energy and environmental challenges, and the large-scale application of magnesium alloy is an important support to achieve this goal. However, magnesium alloys have a sharp drop in alloy strength in temperature environments exceeding 120-150 ℃, and a severe grain boundary slip, which is difficult to bear loads for a long time, greatly limits their application in medium and high temperature environments such as engine peripheral components, transmission housings, aerospace high temperature structural members, and the like. In order to improve the heat resistance of magnesium alloys, alloying, in particular, adding rare earth elements (such as Gd, Y, nd, etc.) with high melting point and low diffusivity is mainly explored from two aspects. These elements can form a second phase with high thermal stability in the magnesium matrix, pinning grain boundaries, and hindering dislocation movement, thereby increasing high temperature strength. Secondly, microstructure control is carried out, and crystal grains are refined and high-density defects (such as dislocation and twin crystals) are introduced through plastic deformation (such as extrusion and rolling) and heat treatment so as to strengthen the alloy. However, the prior art still faces the bottleneck that on one hand, the high rare earth content greatly increases the cost, and excessive addition can cause brittle phase increase and damage the plasticity, on the other hand, the traditional thermal deformation is easy to trigger recrystallization to form an equiaxed crystal structure, and although the room temperature plasticity can be improved, the recrystallized grain boundary is easy to become a weak link at high temperature, migration and sliding occur, and the creep resistance is unfavorable. Therefore, how to construct a strengthening structure which is stable at medium and high temperature and can effectively block dislocation and grain boundary movement in magnesium alloy through innovative component design and process design on the premise of not excessively depending on high rare earth content becomes a key for breaking through the heat resistance bottleneck of the existing magnesium alloy. Disclosure of Invention The invention aims to solve the problems of insufficient creep resistance of the existing magnesium alloy in a medium-high temperature environment and high cost and plastic damage caused by dependence on high rare earth content, and provides a medium-high temperature creep resistance magnesium alloy which improves the creep resistance through multielement segregation. Under the combined action of specific alloy component design and a thermomechanical treatment process, the alloy not only forms a kink zone interface with high stability, but also creates conditions for precipitation of nano phases in the subsequent high-temperature service process by element segregation, thereby realizing the effective inhibition of creep deformation in a multi-scale and whole process. It should be noted that, in the present invention, unless otherwise specified, reference to the specific meaning of "comprising" as defined and described by the composition includes both the open meaning of "comprising", "including" and the like, and the closed meaning of "consisting of", "consisting of" and the like. The technical scheme is that the medium-high temperature creep-resistant magnesium alloy comprises, by mass, mg- (9.0-15.0) A- (0.2-1.0) B- (0.5-2.0) Zn, namely 9.0-15.0 wt% of element A, 0.2-1.0 wt% of element B, 0.5-2.0 wt% of Zn and the balance of Mg, wherein the element A is one or more of gadolinium, yttrium and dysprosium, and the element B is manganese and/or calcium. Further, in the medium-high temperature creep-resistant magnesium alloy, at least one rare earth element in the A element exceeds 40 wt percent of the solid solution limit. Further, in the medium-high temperature creep-resistant magnesium alloy, gadolinium content exceeds 9.4 wt percent, yttrium content exceeds 5.08 percent by weight, or dysprosium content exceeds 10.23: 10.23 wt percent. Further, the kink zone interface percentage of the medium-high temperature creep-resistant magnesium alloy is more than