Tensile and creep properties of Mg-9Al based alloys containing bismuth

来源期刊：中国有色金属学报(英文版)2000年第4期

论文作者：袁广银 孙扬善 张为民 孙建荣

文章页码：469 - 472

Key words：magnesium alloys; bismuth; microstructure; mechanical properties

Abstract: The microstructure and mechanical properties of Mg-9Al-0.8Zn(AZ91) alloys containing bismuth were investigated. Adding bismuth to AZ91 base alloys results in significant increase of tensile strength at both ambient temperature and 150℃, especially the creep rupture life at 150℃, while slight decrease of ductility. Microstructure observations indicate that the addition of bismuth modifies the microstructure of as-cast alloy and makes the β(Mg₁₇Al₁₂) phase finer and more uniform in distribution. Furthermore, the discontinuous precipitation is suppressed greatly during aging process. When the bismuth addition amount exceeds 0.5%, rod-shape Mg₃Bi₂ precipitates with hexagonal D5₂ structure, which have high thermal stability and strengthen both the matrix and grain boundaries.