Stress‐Induced Optimization of Electrochemical Corrosion Behavior and Fatigue Properties of Magnesium Alloys Under the Regulation of Diffusion Layer Depth

This study deposits magnetron‐sputtered aluminum (Al) films on ZK60 magnesium (Mg) substrates with residual stress ranging from −88.6 to 1.9 MPa to investigate stress‐dependent Al‐Mg interdiffusion and its influence on fatigue behavior under stress‐controlled sinusoidal loading at stress ratio R = 0.1 and electrochemical behaviors in 3.5 wt.% NaCl solution. Substrate residual stress is regulated by annealing at 100°C for 20 min. Residual stress serves as a driving force to accelerate atomic infiltration. Compared with stress‐free samples, specimens with 88.6 MPa compressive residual stress form a three‐fold thicker Al‐Mg interdiffusion layer. Thickened diffusion layers generate smooth Al‐Mg transition zones, reducing corrosion current density by three times and doubling fatigue cycles under specified loading, which enhances coating corrosion resistance and fatigue performance. A COMSOL diffusion model coupled with residual stress is established in this work to theoretically verify stress‐accelerated interfacial diffusion and elucidate the underlying mechanisms behind experimental observations.