Stress corrosion cracking and corrosion fatigue cracking behavior of A7N01P‐T4 aluminum alloy

Abstract

A modified single edge notch tension (SENT) specimen exposed to saline environment was used to investigate the stress corrosion cracking and corrosion fatigue cracking behavior of A7N01P‐T4 aluminum alloy. The crack propagation rate was determined, the microstructure, crack growth path, and the fracture surfaces of specimens were examined by optical microscopy (OM) and scanning electron microscopy (SEM). The results showed that the stress corrosion cracking rate of A7N01P‐T4 alloy in 3.5% NaCl was three orders lower than that of corrosion fatigue crack propagation rate. Mg and Zn segregation at the grain boundaries increased the stress corrosion crack susceptibility. The grain orientation had a significant effect on the crack propagation performance, and the high angle grain boundaries were susceptible to cracking. Hydrogen embrittlement was the primary cause of stress corrosion crack and corrosion fatigue crack propagation.