Influence of high-temperature rolling and annealing on texture evolution and mechanical properties of Mg -0.4wt%Bi alloy

Abstract

This work focuses on exploring how sequential thermomechanical processing—specifically hot rolling followed by thermal annealing—affects the microstructural features, crystallographic texture evolution, and deformation response of a Mg-0.4 wt% Bi alloy. The alloy underwent hot deformation at 300°C, after which it was subjected to annealing at three distinct temperatures: 225°C, 325°C, and 425°C. These treatments were systematically analyzed to assess their influence on grain size reduction, texture transformation, and resultant mechanical characteristics.. Scanning Electron Microscopy (SEM) revealed an increase in grain size from 19.88μm at 225°C to 22.79μm at 325°C, indicating full recrystallization. Annealing at 425°C resulted in a significant 61% increase in grain size, reaching 36.77μm, which reflects substantial grain growth at higher temperatures. Electron Backscatter Diffraction (EBSD) assessments performed at varying annealing temperatures revealed that as the temperature rose from 225°C to 325°C, there was a notable decline in peak texture intensity, dropping from 22.01 to 15.10., attributed to texture weakening that leads to random nucleation of grains, However, further increase in temperature to 425°C, maximum texture intensity increased to 20.16μm, pointing to the dominating grain growth orientation.