Effect of bismuth and antimony additions on the microstructure and mechanical properties of AZ91 magnesium alloy

被引：128

作者：

Guangyin, Yuan ^{[1
]}

Yangshan, Sun ^{[2
]}

Wenjiang, Ding ^{[1
]}

机构：

[1] Institute of Foundry Engineering, Coll. Mat. Sci. Eng., Shanghai J., Shanghai, China

[2] Dept. of Mat. Sci. and Engineering, Southeast University, 210096, Nanjing, China

来源：

Materials Science and Engineering: A | 2001年 / 308卷 / 1-2期

关键词：

Antimony - Bismuth - Composition effects - Creep - Metallographic microstructure - Thermodynamic stability - Yield stress;

D O I：

10.1016/S0921-5093(00)02043-8

中图分类号：

学科分类号：

摘要：

The effects of bismuth and antimony additions on the microstructure and mechanical properties of AZ91 alloy have been studied. Results show that a small amount of bismuth or antimony additions to AZ91 increases the yield strength and creep resistance significantly at elevated temperatures up to 200°C. The highest creep resistance has been obtained from the alloy with combined additions of bismuth and antimony. The activation energies of the steady-state creep for AZ91-based alloys studied were close to that of pure magnesium self-diffusion, indicating that dislocation climb is responsible for the creep mechanism under the present conditions. Microstructural observations reveal that the additions of bismuth or antimony have the effect of refining the β (Mg17Al12) precipitates in as-cast alloys and suppressing discontinuous precipitation of the β phase effectively during the aging process. Some rod-shaped Mg3Bi2 or Mg3Sb2 particles distributed mainly at grain boundaries have been observed in the alloys with bismuth or antimony additions. Both Mg3Bi2 and Mg3Sb2 have a high thermal stability and play important roles in improving creep resistance of the alloys at elevated temperatures. © 2001 Elsevier Science B.V. All rights reserved.

引用

页码：38 / 44