Influence of aqueous salt environments on fatigue response of SiC p reinforced aluminium alloys

Abstract

The low cycle fatigue response of aluminium alloy 2124 reinforced with silicon carbide particulates produced by a commercial powder metallurgy route has been evaluated. This assessment includes measurements of fatigue crack growth rates and ‘total life to failure’ experiments. The relative performance under aqueous saline environments, namely total immersion in a 3.5% salt solution and exposure to a salt fog of similar concentration, were then characterised. While the alloy essentially demonstrates an insensitivity to saline environments in terms of its crack growth characteristics, a process of surface corrosion and pitting is highlighted and deemed responsible for significant reductions in the total fatigue life. The implications for engineering designs attempting to make use of this class of metal matrix composite are discussed.