Effect of long period stacking ordered phase on the microstructure, texture and mechanical properties of extruded Mg-Y-Zn alloy

The effect of long period stacking ordered (LPSO) phase on the microstructure, texture and mechanical properties of extruded Mg-Y-Zn alloys with compositions of Mg98.5Y1Zn0.5, Mg95.5Y3Zn1.5 and Mg92.5Y5Zn2.5 (at%), was systematically investigated. The LPSO phases were aligned along the extrusion direction (ED) in the as-extruded Mg-Y-Zn alloys, and significantly enhanced the dynamic recrystallization (DRX) process during the hot extrusion. With the increase of LPSO phase, the degree of DRX process of Mg alloy was more completed, the growth of the DRXed grains resulted in the grain coarsening, and the following phenomena were also observed that the conventional basal fiber texture was remarkably weakened, a novel texture component of <0 0 0 1>//ED appeared in the Mg alloys with higher volume fraction of LPSO phase. The microhardness and tensile yield stress (TYS) of Mg-Y-Zn alloy was improved by LPSO phase, but the ductility was degraded. The strengthening effect of LPSO phase was dominant over that from the grain refinement and texture. (c) 2012 Elsevier B.V. All rights reserved.