粉末冶金Mg-6Al-xZr合金的组织与力学性能

Microstructure and mechanical properties of P/M Mg-6Al-xZr alloys

采用机械合金化和粉末冶金技术制备了Mg-6Al-xZr(x=0、3、6、9)(质量分数)合金,研究了Zr含量对合金微观组织以及力学性能的影响。结果表明:550℃烧结态合金的组织由Mg基体、Zr以及Mg17Al12相组成,同时存在大量微孔;随着Zr含量的升高,Mg基体晶粒尺寸以及孔隙均变小,合金显微组织细化;合金的硬度和抗弯强度随Zr含量的增加而提高;650℃复烧后Al元素向Zr颗粒内部扩散并生成中间相Al3Zr,合金的力学性能进一步提高。

Mg-6Al-xZr（x = 0, 3, 6, 9, mass percent） alloys were fabricated by ball milling and powder metallurgy. Effects of Zr contents on the microstructure and mechanical properties of alloys were investigated. The results show that microstructure of alloys sintered at 550℃ consists of Mg matrix, Zr and Mg17Al12, with large number of micro- pores. Size of Mg grains and pores decreases with increasing Zr content, and microstructure of alloys is more refining. Hardness and bending strength increase with the increasing Zr content. During re-sintering process at 650℃ , element Al diffuses into Zr particles, forming intermediate phase A13Zr, and mechanical properties of alloys further increase.