The effect of precipitates on the mechanical properties of ZK60-Y alloy

This paper investigated the influence of the microstructure on the mechanical properties of the forged ZK60-Y alloy under different heat treatments (T4, T5 and T6). The results show that the alloy at the direct artificial ageing treatment has superior strength and plasticity. X-ray analysis, SEM fracture observation and EDAX spectrum analysis reveal that bulk w-Mg3Y2Zn3 and coarsened rod-like MgZn′(β′1β′1) phases have great influence on the tensile properties of the alloy. Further investigations of the alloy aged at 180 °C, 200 °C and 225 °C for 0.5–100 h, respectively, suggest that the mechanical properties and the fracture characteristics are closely related with the variation of the rod-like β′1β′1 precipitation. The fracture observation of the samples aged at 200 °C indicates that with the increase of the density and the size of the rod-like β′1β′1 precipitation, more semi-cleavage planes will appear on the fracture surfaces.