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CN-121976100-A - High-temperature-resistant creep-resistant die-casting magnesium alloy and preparation method thereof

CN121976100ACN 121976100 ACN121976100 ACN 121976100ACN-121976100-A

Abstract

The invention discloses a high-temperature-resistant creep-resistant die-casting magnesium alloy and a preparation method thereof, and relates to the technical field of nonferrous metal materials. The high-temperature-resistant creep-resistant die-casting magnesium alloy comprises the following components in percentage by mass: al: 5.1-7.4%, la: 0-6.5%, ce: 0-6.5% (la+ce=4.4-6.5%), sr: 0.1-0.5%, sm: 0.001-0.5%, mn: 0.15-0.35%, zn: 0.01-0.3%, Y: 0.001-0.05%, nd: 0.001-0.05%, gd: 0.001-0.05%, be: 5-15 ppm, the balance being Mg and impurity elements. The invention provides an economic and effective high-temperature-resistant creep-resistant magnesium alloy suitable for die casting through alloy regulation and control, and the creep strain quantity is lower than 0.03% under the creep conditions of 105 ℃, 60Mpa and 50 h.

Inventors

  • LIN MAOGU
  • ZHANG YUQIN
  • YIN TIAN
  • ZHANG XU
  • CAO CHANG
  • YAN GUOQING
  • WEI JIE
  • SHI YE

Assignees

  • 山西瑞格金属新材料有限公司

Dates

Publication Date
20260505
Application Date
20260210

Claims (10)

  1. 1. The high-temperature-resistant creep-resistant die-casting magnesium alloy is characterized by comprising the following components in percentage by mass: Al：5.1-7.4%、La：0-6.5%、Ce：0-6.5%、Sr：0.1-0.5%、Sm：0.001-0.5%、Mn：0.15-0.35%、Zn：0.01-0.3%、Y：0.001-0.05%、Nd：0.001-0.05%、Gd：0.001-0.05%、Be：5-15ppm, The balance of Mg and impurity elements; wherein La+Ce=4.4-6.5%, and the total content of impurity elements is less than or equal to 0.1%.
  2. 2. The high temperature resistant creep resistant die cast magnesium alloy of claim 1, wherein the composition comprises, in mass percent: Al：5.1-6%、La：0-5.5%、Ce：0-5.5%、Sr：0.1-0.3%、Sm：0.001-0.5%、Mn：0.15-0.35%、Zn：0.01-0.3%、Y：0.001-0.05%、Nd：0.001-0.05%、Gd：0.001-0.05%、Be：5-15ppm, The balance of Mg and impurity elements; wherein La+Ce=4.4-5.5%, and the total content of impurity elements is less than or equal to 0.1%.
  3. 3. The high temperature resistant creep resistant die cast magnesium alloy of claim 1, wherein the composition comprises, in mass percent: Al：6-7.4%、La：0-5.5%、Ce：0-5.5%、Sr：0.1-0.3%、Sm：0.001-0.5%、Mn：0.15-0.35%、Zn：0.01-0.3%、Y：0.001-0.05%、Nd：0.001-0.05%、Gd：0.001-0.05%、Be：5-15ppm, The balance of Mg and impurity elements; wherein La+Ce=4.4-5.5%, and the total content of impurity elements is less than or equal to 0.1%.
  4. 4. The high temperature resistant creep resistant die cast magnesium alloy of claim 1, wherein the composition comprises, in mass percent: Al：5.1-6%、La：0-6.5%、Ce：0-6.5%、Sr：0.1-0.3%、Sm：0.001-0.5%、Mn：0.15-0.35%、Zn：0.01-0.3%、Y：0.001-0.05%、Nd：0.001-0.05%、Gd：0.001-0.05%、Be：5-15ppm, The balance of Mg and impurity elements; wherein La+Ce=5.5-6.5%, and the total content of impurity elements is less than or equal to 0.1%.
  5. 5. The high temperature resistant creep resistant die cast magnesium alloy of claim 1, wherein the composition comprises, in mass percent: Al：6-7.4%、La：0-6.5%、Ce：0-6.5%、Sr：0.1-0.3%、Sm：0.001-0.5%、Mn：0.15-0.35%、Zn：0.01-0.3%、Y：0.001-0.05%、Nd：0.001-0.05%、Gd：0.001-0.05%、Be：5-15ppm, The balance of Mg and impurity elements; wherein La+Ce=5.5-6.5%, and the total content of impurity elements is less than or equal to 0.1%.
  6. 6. The high temperature resistant creep resistant die cast magnesium alloy of claim 1, wherein the composition comprises, in mass percent: Al：6-7.4%、La：0-6.5%、Ce：0-6.5%、Sr：0.3-0.5%、Sm：0.001-0.5%、Mn：0.15-0.35%、Zn：0.01-0.3%、Y：0.001-0.05%、Nd：0.001-0.05%、Gd：0.001-0.05%,Be：5-15ppm, The balance of Mg and impurity elements; wherein La+Ce=5.5-6.5%, and the total content of impurity elements is less than or equal to 0.1%.
  7. 7. The high temperature resistant creep resistant die casting magnesium alloy according to any one of claims 1 to 6, wherein the mass ratio of Al, la, ce is 1≤Al (La+Ce) 1.5, the mass ratio of Al, sr, sm is (Sr+Sm) Al 0.15 or less, and the mass ratio of La, ce, sr, sm is (Sr+Sm) La+Ce 0.15 or less.
  8. 8. A method for producing the high temperature resistant creep resistant die cast magnesium alloy according to any one of claims 1 to 7, comprising the steps of: preparing raw materials according to the composition of alloy components, smelting and refining to obtain a magnesium alloy melt, and die casting the magnesium alloy melt to obtain the high-temperature-resistant creep-resistant die casting magnesium alloy.
  9. 9. The method for preparing high temperature resistant and creep resistant die casting magnesium alloy according to claim 8, wherein the smelting temperature is 680-750 ℃, and SF 6 ＋CO 2 gas mixture is introduced for protection during the smelting process.
  10. 10. The method for preparing the high temperature resistant and creep resistant die casting magnesium alloy according to claim 8, wherein the parameters of die casting comprise 35-45MPa of injection pressure, 4.5-5.5m/s of injection speed, 190-210 ℃ of die temperature, and introducing SF 6 ＋N 2 mixed gas for protection in the die casting process.

Description

High-temperature-resistant creep-resistant die-casting magnesium alloy and preparation method thereof Technical Field The invention relates to the technical field of nonferrous metal materials, in particular to a high-temperature-resistant creep-resistant die-casting magnesium alloy and a preparation method thereof. Background Along with the requirements of energy conservation and emission reduction and the upgrading requirements of equipment manufacturing industry, the strategic position of lightweight materials in the fields of automobiles, aerospace, electronic communication and the like is increasingly highlighted. The magnesium alloy is used as the lightest metal structural material, the density of the magnesium alloy is only 2/3 of that of the aluminum alloy and 1/4 of that of steel, and the magnesium alloy has obvious weight reduction advantage. However, conventional magnesium alloys such as AZ, AM series show significant strength drop and creep acceleration at temperatures above 100 ℃, which are mainly due to their low melting point characteristics and the activation of creep mechanisms such as grain boundary sliding, dislocation climbing, etc. at high temperatures. Especially in the working environments of key components such as automobile engine cylinder bodies, gearbox shells, aviation engine cabins and the like, materials need to bear high-temperature loads for a long time, and the heat resistance of the traditional magnesium alloy can not meet the actual engineering requirements. The performance short plate severely restricts the application expansion of the magnesium alloy under the high-temperature working condition, and development of a novel high-temperature-resistant creep-resistant magnesium alloy system is needed. Disclosure of Invention The invention aims to provide a high-temperature-resistant creep-resistant die-casting magnesium alloy and a preparation method thereof, so as to solve the problems in the prior art. In order to achieve the above object, the present invention provides the following solutions: according to one of the technical schemes, the high-temperature-resistant creep-resistant die-casting magnesium alloy comprises the following components in percentage by mass: Al：5.1-7.4%、La：0-6.5%、Ce：0-6.5%、Sr：0.1-0.5%、Sm：0.001-0.5%、Mn：0.15-0.35%、Zn：0.01-0.3%、Y：0.001-0.05%、Nd：0.001-0.05%、Gd：0.001-0.05%、Be：5-15ppm, The balance of Mg and impurity elements; Wherein, la+Ce=4.4-6.5% (namely La and Ce are not 0 at the same time, and specifically three conditions are included: ①La=0,Ce=4.4-6.5%;②Ce=0,La=4.4-6.5%;③ La and Ce are not 0, and La+Ce=4.4-6.5%), and the total content of impurity elements is less than or equal to 0.1%. The addition of Al can obviously improve the fluidity of the magnesium alloy, and is beneficial to the filling capacity in the casting process because the Al can reduce the melting point of the alloy and promote the formation of eutectic structures. However, the Al-formed β -Mg 17Al12 phase is prone to softening at high temperatures, resulting in reduced creep resistance, especially at temperatures exceeding 100 ℃. In contrast, the addition of La and/or Ce can significantly enhance the high temperature creep resistance of magnesium alloys, mainly by forming a high melting point thermally stable phase AlLa phase and/or AlCe phase, inhibiting grain boundary sliding and dislocation movement. In addition, the addition of Sr and Sm can form various heat-stable compounds (such as Al 4Sr+Al11Sm3) with high volume fraction, and the grain boundary is commonly pinned, so that the high-temperature performance and creep resistance are improved by 1+1> 2. In addition, the addition of Zn can reduce the liquidus temperature of the alloy and reduce the solidification interval, thereby improving the fluidity, improving the die casting performance, reducing the shrinkage and isopiestic casting defects, purifying the melt, eliminating the harmful influence of iron impurities, forming a small amount of Al 6 Mn phase, enabling the generation of Al 6 Mn phase to Be used as heterogeneous nucleation point in the smelting process, promoting the refinement of alpha-Mg crystal grains, enabling finer crystal grains to mean more crystal boundaries, effectively preventing dislocation movement, further improving the strength and plasticity of the alloy, further optimizing the alloy performance (forming performance, mechanical performance, high temperature resistance and creep resistance) through the synergistic effect between the Al 6 Mn phase, alLa, alCe, al 4 Sr, al 11Sm3 and other phases, obviously improving the oxidation resistance and flame retardant performance of the magnesium alloy melt, improving the processing performance, and further improving the high temperature resistance and creep resistance of the alloy by adding a small amount of heavy rare earth elements such as Y, nd and Gd. In addition, the rare earth elements La and/or Ce and Sr with lower cost have higher addition proportio