Microstructure and mechanical properties of as-cast and heat treated Mg-15Gd-3Y alloy  

作　　者：张磊 董选普 李继强 王文俊 王爱华 樊自田 

机构地区：[1]State Key Laboratory of Material Forming and Mould & Die Designing,Huazhong University of Science and Technology [2]School of Me-chanical and Energy,Ningbo Institute of Technology,Zhejiang University

出　　处：《Journal of Rare Earths》2011年第1期77-82,共6页稀土学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (50775085);Special Fund for Basic Research and Operating Expenses of Central College (M2009061);Natural Science Foundation of Ningbo City(2008A610049)

摘　　要：The microstructure evolution and mechanical properties of Mg-15Gd-3Y alloy were investigated in the as-cast and heat treated conditions. The microstrucmre evolution from as-cast to cast-T4 states involved a-Mg solid solution＋Mg5（Gd,Y） phase→a-Mg supersaturated solid solution＋rare earths compound Mg3（Gdl.26,Y0.74）→a-Mg supersaturated solid solution＋rare earths compound Mg3（Gd0.Tas,Y1.255）. It showed that 480 ℃/4 h was the optimal solution treatment parameter. If the solution temperature was high or the holding time was long, such as 520 ℃/16 h, an overheating phenomenon would be induced, which had a detrimental effect on the mechanical properties. When ageing at 225 and 200℃, the alloy would exhibit a significant age-hardening response and great long-time-age-hardening potential, respectively. The best mechanical properties were obtained at the parameters of 480 ℃/4 h＋225 ℃/16 h, with the UTS of 257.0 MPa and elongation of 3.8%.The microstructure evolution and mechanical properties of Mg-15Gd-3Y alloy were investigated in the as-cast and heat treated conditions. The microstrucmre evolution from as-cast to cast-T4 states involved a-Mg solid solution＋Mg5（Gd,Y） phase→a-Mg supersaturated solid solution＋rare earths compound Mg3（Gdl.26,Y0.74）→a-Mg supersaturated solid solution＋rare earths compound Mg3（Gd0.Tas,Y1.255）. It showed that 480 ℃/4 h was the optimal solution treatment parameter. If the solution temperature was high or the holding time was long, such as 520 ℃/16 h, an overheating phenomenon would be induced, which had a detrimental effect on the mechanical properties. When ageing at 225 and 200℃, the alloy would exhibit a significant age-hardening response and great long-time-age-hardening potential, respectively. The best mechanical properties were obtained at the parameters of 480 ℃/4 h＋225 ℃/16 h, with the UTS of 257.0 MPa and elongation of 3.8%.

关 键 词：Mg-15Gd-3Y alloy solution heat treatment microstructure AGE-HARDENING mechanical properties rare earths 

分 类 号：TG166.4[金属学及工艺—热处理]