Recrystallization mechanisms, grain refinement, and texture evolution during ECAE processing of Mg and its alloys

Abstract

This article presents key findings from a study of the microstructural evolution and grain size refinement of equal-channel angular extrusion (ECAE)-processed Mg and Mg-based alloys. Firstly, we delineate the experimental trends and material characteristics of grain size distribution and texture of as-cast pure Mg and rolled AZ31B which were processed via ECAE. We then identify and describe the primary controlling mechanisms of dynamic recrystallization (DRX) and twinning and how their interaction affects the overall refinement process. Secondly, using preliminary results from ongoing studies of other Mg-based model binary and ternary systems, with access to precipitation hardening mechanisms, we present new opportunities and beneficial outcomes that could affect and control the material's microstructural properties. Thirdly, we provide a summary of prior and concurrent modeling and simulation efforts that capture and emulate the experimentally observed trends of DRX and illustrate their predictive capability. We then, within a Materials-by-Design and Optimization framework, conclude with implications for future developments in Mg alloy research.