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

The tensile and tensile creep properties of the as-cast Mg-5Zn-2.5Er (in wt.%) alloy strengthened by icosahedral quasicrystalline phase (1-phase) were studied. The Mg-5Zn-2.5Er alloy had better tensile properties both at room temperature and 175 degrees 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 degrees C and 70 MPa for 100 h. 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 alpha-Mg matrix can pin the dislocation effectively, improving the creep resistance of the alloy. (C) 2009 Elsevier B.V. All rights reserved.