Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 15 No. 4 August 2005|
（1. Department of Materials Science and Engineering, Southeast University,
Nanjing 210096, China;
2. Nanjing Welbow Metals Co Ltd, Nanjing 211221, China）
Abstract: The creep resistance of the alloy Mg-4Al-2RE-2Ca(AEC422) and the base alloy AE42 was studied. The results reveal that the precipitated phases of AEC422 consist of Al2La and Al2Ca by contrast with the precipitated phase Al11La3 in AE42, which is instable and decomposes to Al2La and Al at high temperature. Creep resistance of AEC422 is significantly improved compared with that of AE42. The microstructure of AEC422 has no obvious changes after creep test at 175℃ and 70MPa, as compared to that before creep test, indicating that Al2La and Al2Ca have high thermal stability. Especially Al2Ca phase largely increases the strength of the grain boundaries in AEC422, which accounts for the creep resistance improvement.
Key words: creep resistance; grain boundaries sliding; intermetallic phase