Stress corrosion cracking of cast 7XXX aluminium fibre reinforced composites

Abstract Using continuous immersion techniques, the stress corrosion cracking (SCC) behaviour of cast and heat-treated Al–6%Zn–1%Mg (Al-6-1) and Al–6%Zn–1%Mg–1%Ag (Al-6-1-1) metal matrix composites were evaluated. It was found that the Al-6-1-1 composites exhibit longer lifetimes compared to the Al-6-1 when tested under various SCC conditions. Fractography and scanning electron microscopy studies performed on stress-corroded specimens found evidence of the respective roles played by the dissolution and hydrogen embrittling mechanisms in the initiation and propagation of stress corrosion cracks within these materials.