Role of recovery in the microstructure development and mechanical behavior of a ductile Mg-Zn-Nd-Y-Zr alloy: an analysis using EBSD data and crystal plasticity simulations

Abstract

A highly deformable Mg-Zn-Nd-Y-Zr alloy was investigated in terms of anisotropic and temperature-dependent mechanical behavior, with an emphasis on the microstructural changes. Uniaxial tension tests were conducted along the rolling (RD) and transverse (TD) directions at room temperature (298 K) and at 498 K, during which a series of ex-situ EBSD scans were obtained. In addition to quantitative texture analysis based on the EBSD scans, the relative contributions of various slip systems were estimated via slip trace analysis. Moreover, the effect of static recovery was investigated by additional two-step tension tests with intermediate annealing at 498 K. The microstructure development due to recovery was analyzed via ex-situ EBSD scans by analyzing the grain average misorientation, kernel average misorientation, and in-grain misorientation axis evolution. Experimental results were interpreted using crystal plasticity simulations based on the incremental elasto-visco-plastic self-consistent polycrystal model (ΔEVPSC). Remarkably, a single set of parameters sufficed to describe the complex anisotropic and temperature-dependent behavior of the Mg-Zn-Nd-Y-Zr alloy by utilizing a dislocation density-based hardening model (DDH). The recovery, mainly of non-basal dislocations, significantly affected the flow stress responses, which allowed not only to describe the hardening behavior but also the anisotropy, characterized by the R-value and texture.