Characterization and modeling of micro/substructure evolution in aluminum alloy

Abstract

For materials with high stacking fault energy (SFE), such as aluminum alloys, dynamic recovery (DRV) and dynamic recrystallization (DRX) are critical softening mechanisms during plastic deformation, resulting in microstructural and substructural evolution.This study investigates the effect of compression parameters on the microstructural evolution of an AA1050 aluminum alloy at elevated temperatures. The formation of well-defined substructures and the subsequent development of DRX grains indicate that recrystallization can occur during high-temperature compression. The mechanisms driving microstructural evolution and DRX are summarized by analyzing the flow stress, variations in misorientation angle, DRX fraction, and the distribution of subgrains and grain boundaries.The mechanisms of subgrain generation, refinement, and coarsening are analyzed based on experimental investigations of microstructure and substructure. Two subgrain size evolution models (empirical and substructure-based) are applied with multiple internal state variables. These models successfully simulate average subgrain size, with both experimental and simulated results reproducing the thermo-mechanical behavior during continuous deformation.Finally, the laws governing hot deformation and microstructural evolution are integrated into a dislocation-based model framework, which primarily includes the evolution of internal dislocation density, wall dislocation density, subgrain size, subgrain misorientation, and flow stress. This dislocation model is successfully applied to the microstructural evolution of AA1050 and other aluminum alloys under various deformation conditions.