Microstructural tailoring via shot peening synergistically enhances corrosion, wear, and tribocorrosion resistance of Al-Zn-Mg-Cu alloy

This study revealed that mechanical shot peening (SP) achieved synergistic improvement in corrosion, wear, and tribocorrosion resistance of an Al-Zn-Mg-Cu alloy by inducing tailored microstructural alterations. The SP treatment produces a gradient-deformed layer characterized by high dislocation density and compressive residual stresses, accompanied by refinement of η/η′ precipitates, disrupted continuous grain boundary precipitates (GBPs), and narrowed precipitation-free zones (PFZs). These microstructural modifications achieve a unique combination of high corrosion and exceptional dry wear resistance, with an 18.8 % reduction in corrosion current density (I_corr), a 350 % enhancement in impedance modulus (Z_mod), a 47.4 % decrease in pitting density, a 59.5 % mitigation in intergranular corrosion (IGC) susceptibility, and a 28.8–36.6 % improvement in dry sliding wear resistance. Beyond conventional single-property improvements, SP treatment suppresses the process of corrosion-accelerated wear and wear-accelerated corrosion during tribocorrosion by mitigating micro-galvanic coupling and establishing anodic dissolution barrier. The pre-existing dislocation structures and residual stresses inhibit subsurface damage under mechanical-electrochemical synergy, achieving a 15.9–22.1 % decrease in I_corr during tribocorrosion, a 9.1–31.9 % reduction in corrosive wear rates, along with enhanced repassivation kinetics. The present work establishes a clear microstructure-property correlation and provides valuable insights for SP-treated aluminum alloys with superior durability in multi-degradation aerospace environments.