113 Observations of Corrosion Fatigue Crack Initiation of High-Strength Aluminum Alloy by Scanning Atomic Force Microscopy

Abstract

Corrosion fatigue crack initiation process of a high-strength aluminum alloy, 7075-T651 was observed by means of a scanning atomic force microscopy (AFM). Plane bending fatigue tests were carried out either ill air or in 3% NaCl solution. The fatigue strength in aqueous environment was much lower than that in air. Grain boundaries around specific grains were preferential site of anodic dissolution, and cracks were initiated from these grain boundaries.