Effects of heat treatment on microstructure and mechanical properties of Mg-5Zn-0.63Er alloy

The microstructure evolution of the Mg-5Zn-0.63Er (mass fraction, %) alloy containing quasicrystalline phase (I-phase) under the as-cast condition was investigated via different heat treatments. The results show that apart from the precipitation of the W-phase particles, the I-phase almost dissolves into the matrix after solid solution treatment at 480 degrees C for 10 h (T4 state). The solution-treated alloy was aged at 175 degrees C for 6-100 h (T6 state). The ultimate tensile strength of the peak-aged alloy is approximately 261 MPa companying with an elongation of 10.5%. The improvement of the tensile strength is mainly attributed to the presence of the rod-like MgZn2 particles.