Nanoprecipitates of icosahedral phase in quasicrystal-strengthened Mg-Zn-Y alloys

摘要

Extensive microstructural studies have been performed with respect to the formation of the icosahedral quasicrystalline phase and its relationship to other phases in Mg_(95)Zn_(4.2)Y_(0.8) ally. The icosahedral phase forms as an intergranular eutectic phase as well as precipitates in the matrix.The precipitates are nanosized (typically 50 nm) with a definite orientation relationship with the matrix, sharply faceted on twofold planes which are on the basal and prismatic planes of the matrix. The detailed crystallographic relationship with the matrix is described. The icosahedral phase is occasionally found to coexist with the cubic W-Zn_3Mg_2Y_3 phase with a definite crystallographic relationship.