Effect of Heat Treatment on the Mechanical Properties of Hot-rolled AZMX1100 Alloy

In this study, to investigate the evolution of microstructure and texture, as well as their effect on mechanical properties of AZMX1100 magnesium alloy, AZMX1100 plates were manufactured using the TRC (Twin roll casting) method, which is one of the continuous casting methods With TRC it is possible to reduce the segregation of magnesium alloys, improve the size and distribution of inclusions, and refine grain through rapid cooling. In the TRC-processed HR(0PASS) plate, coarse grains with an average size of 131.3 ± 80.68 μm were observed. Through hot rolling, the grain size was not only significantly refined to 8.58 ± 4.89 μm, primarily due to dynamic recrystallization (DRX) which not only reduced the average grain size, but also weakened the texture intensity. After either homogenization or aging heat treatment followed by hot rolling process, the grain size increased by over twofold. This occurred due to the combined effects of recrystallized grain growth and the high stored deformation energy during rolling. Although the mechanical strength improved progressively with hot rolling due to work hardening and grain refinement in the HR(8PASS) specimen, homogenization heat treatment led to grain growth, resulting in the lowest Vickers hardness and tensile strength in the HR(8PASS)-N specimen. The specimen HR(8PASS)-T6, processed using T6 heat treatment, demonstrated superior mechanical strength with the ultimate tensile strength of 268.3 MPa ± 3.7 and the yield strength of 184.3 MPa ± 2.2. This enhancement in ductility was attributed to the broad dispersion of texture along the transverse direction (TD) and rolling direction (RD) after heat treatment, which effectively reduced anisotropy during tensile deformation.