Microstructure of Mg-8Zn-4Al-1Ca aged alloy  

Mg-8Zn-4Al-1Ca合金的时效微观组织(英文)

作　　者：董允[1] 林小娉[1] 叶杰[1] 郑润国[1] 何娜[1] 

机构地区：[1]东北大学材料与冶金学院,沈阳110819

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第2期310-315,共6页中国有色金属学报（英文版）

基　　金：Project(51141007)supported by the National Natural Science Foundation of China;Project(E2013501096)supported by Hebei Province Natural Science Foundation,China

摘　　要：The microstructure of Mg-8Zn-4Al-1Ca aged alloy was investigated by TEM and HRTEM. The results show that the hardening produced in the Mg-8Zn-4Al-1Ca alloy is considerably higher than that in the Mg-8Zn-4A1 alloy. A dense dispersion of disc-like Ca2Mg6Zn3 precipitates are formed in Mg-8Zn-4Al-1Ca alloy aged at 160 ℃ for 16 h. In addition, the lattice distortions, honeycomb-looking Moir＆#233; fringes, edge dislocations and dislocation loop also exist in the microstructure. The precipitates of alloy aged at 160 ℃ for 48 h are coarse disc-like and fine dispersed grainy. When the alloy is subjected to aging at 160 ℃ for 227 h, the microstructure consists of numerous MgZn2 precipitates and Ca2Mg6Zn3 precipitates. All the analyses show that Ca is a particularly effective trace addition in improving the age-hardening and postponing the formation of MgZn2 precipitates in Mg-8Zn-4Al alloy aged at 160 ℃.利用TEM和HRTEM研究Mg-8Zn-4Al-1Ca合金的时效微观组织。结果表明:Mg-8Zn-4Al-1Ca合金较Mg-8Zn-4A1合金时效硬度显著增高。Mg-8Zn-4Al-1Ca合金在160°C时效16 h,有大量的盘状Ca2Mg6Zn3相沉淀弥散析出,此外,合金的微观组织中还存在晶格畸变、蜂窝状的莫尔条纹、刃型位错及位错环;经48 h时效后合金中沉淀相为粗大的盘状沉淀相和细小、弥散的粒状沉淀相;经227 h时时效后后,其组织中存在大量MgZn2相和Ca2Mg6Zn3相。因此,在Mg-8Zn-4Al-1Ca时效160°C的合金中添加Ca元素能有效提高合金的时效硬度及促进MgZn2强化相的生成。

关 键 词：Mg-8Zn-4Al-1 Ca alloy age hardening Ca2Mg6Zn3 Moire fringe 

分 类 号：TG146.22[一般工业技术—材料科学与工程]