Enhanced age-hardening response and microstructure study of an Ag-modified Mg–Sn–Zn based alloy

Abstract

A new Mg–Sn–Zn based alloy modified with a small amount of Ag exhibits a significantly higher aging peak than that of the base alloy and at a considerably shorter aging time. The enhanced aging response of the Ag-modified alloy is ascribed to the precipitation of densely distributed MgZn₂ needles and Mg₂Sn plates stimulated by the Ag. A wide and low plateau behind the hardness peak could be associated with rod-shaped precipitates of the orthorhombic Mg₅₄Ag₁₇ phase, aligned with the hexagonal axis of the Mg matrix.

Keywords:

• magnesium alloys
• TEM
• microstructure
• precipitation
• hardness

Acknowledgements

The experimental alloys were prepared at the Chinese Academy of Science by the group of Professor R-S Chen. This work was supported by National Basic Research Program of China (No. 2009CB623704) and National Nature Science Foundation of China (No. 51171088).