Tensile and creep behaviors of Mg–5Zn–2.5Er alloy improved by icosahedral quasicrystal

Abstract

The tensile and tensile creep properties of the as-cast Mg–5Zn–2.5Er (in wt.%) alloy strengthened by icosahedral quasicrystalline phase (I-phase) were studied. The Mg–5Zn–2.5Er alloy had better tensile properties both at room temperature and 175°C than AE42 and Mg–5Zn alloys. Compared to AE42 alloy, the as-cast Mg–5Zn–2.5Er alloy had smaller steady-state creep rate and total creep strain under the creep conditions of 175°C and 70MPa for 100h. The better creep resistance of the Mg–5Zn–2.5Er was mainly due to the formation of I-phase with high-thermal stability distributed along grain boundary. Moreover, microstructure analysis indicated that some fine precipitates in the α-Mg matrix can pin the dislocation effectively, improving the creep resistance of the alloy.