Precipitation behavior of bulk nanocrystalline GW103K alloy induced by surface mechanical attrition treatment

Precipitation hardening plays a significant role in improving the strength of Mg-RE (RE = rare earth) alloy due to the formation of precipitates. It is vital to control the precipitation behavior in order to optimize the mechanical properties of Mg-RE alloy. The present study explored one new way to promote the precipitation behavior of GW103K alloy by surface mechanical attrition treatment (SMAT). As compared with the conventional heat treatment, more precipitates could be formed under a shorter aging duration after SMAT, which results in finer grain size and higher micro hardness than the as-extruded one. The promotion of precipitation behavior is attributed to the high dislocation density induced by SMAT, which leads to a low nucleation energy and a high nucleation rate for the formation of precipitate.