Orientation relationship between 14H-LPSO structured X phase and DO3-type (Mg,Zn)3RE phase in an Mg–Gd–Y–Zn–Zr alloy

Abstract

Abstract Mg-10Gd-3Y-1.8Zn-0.5Zr (wt.%) alloy is prepared by permanent mold casting and further by slow solidification at cooling rate of 0.1 K s− 1. Both X phase with long period stacking ordered structure and DO3-type (Mg,Zn)3 RE phase in the alloy are observed with electron microscopy and X-ray diffraction. Three different X phase/(Mg,Zn)3 RE phases are observed in the alloy. The orientation relationship between X phase and (Mg,Zn)3 RE phase was determined by the composite diffraction patterns, which can be expressed as (0014)X phase//(110)( Mg,Zn )3RE and [110]X phase//[3 32]( Mg,Zn )3RE, (0014)X phase//(110)( Mg,Zn )3RE and [110]X phase//[1 11]( Mg,Zn )3RE, (0014)X phase//(110)( Mg,Zn )3RE and [210]X phase//[1 12]( Mg,Zn )3RE. These results show coherence between X phase and (Mg,Zn)3 RE phase and a very small mismatch in the phase boundaries.