Natural fresh and salt water immersion corrosion trials of composite aluminium syntactic foams

Lightweight composite materials such as syntactic perlite aluminium foams have been gaining much attention from the automotive, aerospace and nautical industries due to their superior mechanical and energy absorbing properties. Yet, there is still no empirical evidence of its mechanical performance under extreme corrosive marine environments. This study reports on 18 months corrosion field trials of such composite foam immersed in natural temperate marine waters off the southeast coast of Australia. Further, natural fresh water corrosion trials were also performed on the foams in order to quantify potential long-term phenomenological factors. Unloading Young's modulus, 1% offset yield stress as well as plateau stress after exposure fall within the scatter of previously reported unexposed samples. The results indicate no short-term loss of mechanical performance for natural exposure conditions. Reasons and implications are discussed.