Mechanical Response and Microstructural Evolution of AZ31B Alloy Sheet in Uni-Axial Tension at Middle-Low Strain Rates and Temperatures

Abstract

To investigate the tensile deformation and mechanical properties of magnesium alloy AZ31B, tensile tests were performed under various strain rates at room temperature and different temperatures at a constant rate. At room temperature, AZ31B was stretched by 10% in the RD, TD, and 45° directions, with strain-hardening exponent calculations showing uniform stress levels. The hardening exponent decreases with increasing strain rate, and dislocation density rises in the RD direction. Prismatic slip is the primary deformation mode, based on Schmid factor calculations. Tests along the RD direction at 100, 150, and 200 °C with a 0.01 s⁻¹ strain rate reveal stress reduction with rising temperature due to a balance between hardening and softening mechanisms. The hardening exponent increases with temperature, indicating strong hardening potential in the AZ31B sheet. EBSD analysis at 100 °C shows a double peak in the polar plot (0002), suggesting pyramidal < c + a > slip as the deformation mechanism. At higher temperatures, dynamic recovery dominates, while grain growth prevails at 200 °C due to insufficient strain for dynamic recrystallization.