Age strengthening behavior and mechanical properties of Mg-Dy based alloys containing LPSO phases

作者：Zou Guodong; Cai Xuecheng; Fang Daqing; Wang Zhen; Zhao Tieshi; Peng Qiuming^*

来源：MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 2014, 620.

DOI：10.1016/j.msea.2014.09.103

• Age strengthening
• Mg alloy

A unique age strengthening behavior of a Mg-2.2Dy-1Cu (at%) alloy containing long-period stacking order (LPSO) phases has been observed during the heat-treatment process for the first time. The results show that both microhardness and compression properties are improved simultaneously. The phase composition and phase transformation have been identified by a transmission electron microscope. The results reveal that the first strengthening peak at 535°C for 4h is mostly associated with the phase transformation from an 18R-type LPSO phase in the grain boundaries to a 14H-type LPSO phase in the grain interiors. However, the secondary peak (535°C for 4h followed by 575°C for 6h) is mainly related to the formation of some nano-sized Mg(Cu, Dy)2 particles, coupling with the decomposition of the 14H-LPSO phase simultaneously.