Stress corrosion crack initiation testing of high strength aluminium alloys using tuning fork type specimens

Abstract

An experimental investigation was carried out into the applicability of various corrosive environments for stress corrosion crack initiation testing of high strength aluminium alloys using constant strain loaded tuning fork type specimens. The effect of surface preparation was also involved. The most important findings were that salt-chromate solution inhibited general corrosion effectively but either did not result in cracking or, at a low pH value, led to an unrealistic ranking of materials as to SCC. The material behaviour experienced under atmospheric conditions was reflected very well by alternate-immersion testing in a salt solution. However, a pickling pre-treatment caused in different alloys a different degree of attack and resulted in substantially shorter lifetimes for alternate immersion testing.