Effects of Symmetric and Asymmetric Pre-Compression Combinations on the Mechanical Properties and Fatigue Behavior of ZK60 Magnesium Alloy

Abstract

Pre-compression modes influence the microstructure of rolled magnesium alloys, thereby enhancing their mechanical and fatigue properties. This study investigates the distribution of dislocations, extension twins, and texture components in rolled ZK60 magnesium alloy sheets subjected to single-pass pre-compression (S-PT3), symmetric pre-compression (S-PT3R3), and asymmetric pre-compression (S-PT3R6). The results indicate that the variation in the orientation of pre-twin textures, leading to differences in the Schmid factor, is the primary cause of the mechanical performance differences observed under different pre-compression modes. In contrast, the hardening effect due to grain refinement is negligible. As the total amount of pre-compression increases, the hardening effect of pre-dislocations becomes more significant. Single-pass pre-compression exhibits a higher fatigue life under large strain amplitudes. Although asymmetric pre-compressed samples show increased overall strength and hardness, their fatigue life and cyclic stability are inferior. During cyclic loading, different pre-compression modes significantly impact the hysteresis curve, deformation mechanisms, stress ratio, and elastic limit amplitude. Symmetric pre-compression samples exhibit superior cyclic stability and fatigue life. Based on different application requirements, suitable pre-compression treatment methods can be selected to optimize the performance of ZK60 magnesium alloys, providing scientific guidance for practical engineering applications.