Comprehensive Mechanical Property Evaluation and Statistical Regression Modeling of AZ91/Graphene Composites After T6 Heat Treatment and Equal Channel Angular Pressing

The AZ91 magnesium alloy serves as an excellent base material for magnesium matrix composites reinforced with graphene—a carbon‐based material renowned for its ability to enhance mechanical strength. The composites were fabricated via the stir casting process. The materials were subjected to T6 heat treatment and ECAP (Equal Channel Angular Pressing) to further improve their mechanical properties. Their mechanical performance was evaluated through tensile and hardness tests, with the results represented by stress–strain curves. The fact that the plastic region is larger than the elastic region in both the T6 and ECAP conditions indicates that the material is more ductile. The best‐performing material in tensile testing was AZ91‑0.2 wt% graphene in the ECAP 1‑pass condition. Furthermore, the relationship between microhardness and UTS was mostly polynomial, and the relationship between crystallite size and both microhardness and UTS values was inverse.