Quasicrystal dissolution and performance of isothermally heat-treated Mg–Zn–Y alloy

Conventional casting method was employed to prepare Mg–Zn–Y alloy only with a-Mg+I-phase; however, the grain size of quasicrystal is quite large in the ascast state.Therefore, isothermal treatment was applied to refine the quasicrystal phase.The result shows that after the Mg–Zn–Y alloy was isothermally treated at 500 °C for several hours, the coarse quasicrystal can be gradually dissolved and thus refined.Generally, the dissolving processes of quasicrystal are slow first and then accelerate;after isothermally treated with 8 h at 500 °C, the quasicrystal is almost completely dissolved into the matrix only with 1–5 lm tiny quasicrystals remained.Refinement of quasicrystal can markedly reduce the wear resistance, but increase the corrosion resistance.