Effect of wrought product thickness and stress ratio on fatigue crack growth behavior of a quaternary aluminium-lithium alloy

Effect of thickness on fatigue crack growth (FCG) behavior has been investi gated at varying stress ratio in a quaternary AI-Li alloy. The thickness ha s been observed to influence FCG behavior in two opposite ways, depending o n stress ratio. The crack closure concept has been invoked to rationalize t he observed behavior. The roughness-induced crack closure is the main gover ning mechanism in the alloy under investigation Factors such as fracture su rface asperity size and severity of plane strain condition have been argued to affect the extent of crack closure, and consequently, fatigue crack gro wth behavior.