Influence of aqueous salt environments on fatigue response of SiCp reinforced aluminium alloys

The low cycle fatigue response of aluminium alloy 2124 reinforced with sili con carbide particulates produced by a commercial powder metallurgy route h as been evaluated. This assessment includes measurements of fatigue crack g rowth rates and 'total life to failure' experiments. The relative performan ce under aqueous saline environments, namely total immersion in a 3.5% salt solution and exposure to a salt fog of similar concentration, were then ch aracterised, While the alloy essentially demonstrates an insensitivity to s aline 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 engi neering designs attempting to make use of this class of metal matrix compos ite are discussed. MST/4543 (C) 2000 IoM Communications Ltd.