Microstructures evolution, texture characteristics and mechanical properties of Mg-2.5Nd-0.5Zn-0.5Zr alloy during the high strain rate hot-rolling

Abstract

The microstructures evolution, texture characteristics and mechanical properties of Mg-2.5Nd-0.5Zn-0.5Zr alloy processed by high strain rate rolling (HSRR) at different temperature were systematically investigated in the current study. The results showed that the initial material was approximately equiaxed grains (23.8 μm) with a large number of divorced eutectic Mg 12 Nd phases precipitated along grain boundaries in a continuous network. After HSRRed, the microstructure was obviously refined, and uniform distributed. The average grain size was refined to 3.63 μm (R673), 2.71 μm (R648) and 2.17 μm (R623), respectively, and corresponding percentage of recrystallization were 46.1%, 49.3% and 63.9%, respectively. R623, R648 presented a strong (0002) basal surface bimodal texture in the RD direction but this texture was in the TD direction in R673, all of which preferential orientation was at 66.3–90° region. An excellent combination of ultimate tensile strength (324 ± 2 MPa), the yield strength (298 ± 3 MPa) and the elongation (6.9 ± 1.5%) were achieved in a fine-grained (2.17 ± 1.17 μm) Mg-2.5Nd-0.5Zn-0.5Zr alloy prepared by HSRR at 623 K. The higher yield strength can be obtained by refinement strengthening, dislocation strengthening, precipitation strengthening and texture strengthening. • Fine-grained alloy sheets with superior properties (298 MPa for tensile yield strength) were achieved by HSRR. • The texture evolution, grain size refining mechanism and strengthening mechanism were analyzed in detail. • Mg-2.5Nd-0.5Zn-0.5Zr alloy sheet was prepared by the high strain rate rolling.