Study on microstructure and mechanical properties of rolled sheets of Mg–7Y–1Nd–0.5Zr alloy: As-cast versus as-homogenized

Abstract

The influences of initial microstructure on the microstructure and texture evolution of the two kinds of as-rolled sheets were investigated by OM, SEM, TEM and EBSD. The results indicated that the as-cast alloy produced a large number of twins, and was almost fully dynamically recrystallized and significantly refined after hot rolling. The average grain size was approximately 90μm. The sheet produced strong (0002) base texture, and the maximum pole intensity was 6.432. The structure of the eutectic structures was face-centered cubic structure (f.c.c.) with lattice constant a=2.22nm. The structure of the cube phase was f.c.c. with lattice constant a=0.52nm. After as-homogenized alloy rolling, the sheet exhibited bimodal grain size distribution with large deformed grains and fine dynamic recrystallization grains. The large deformed grains produced strong (0002) basal texture, and the maximum pole intensity of (0002) basal texture was 7.179. The ultimate tensile strength (UTS), yield tensile strength (YTS) and elongation of as-homogenized alloy rolling were 278, 188MPa and 13.6%, respectively.