Fatigue crack growth behavior of TA15/TC4 dissimilar laminates fabricated by diffusion bonding

Abstract Fatigue crack growth behavior of TA15/TC4 dissimilar laminates produced by diffusion bonding is studied. A sound bonding interface and fine equiaxed microstructure are obtained to improve fatigue damage tolerance with uncompromised tensile properties. TA15 alloy in the dissimilar laminates exhibits a higher fatigue crack growth resistance. EBSD analysis confirms that more α recrystallization occurs in TA15 alloy, which contributes to the relatively random crystallographic orientation and therefore the lower crack propagation rate. Local α grains characterized by high basal or prismatic Schmid factors are activated for plastic deformation accompanied by observation of dislocation lines and tangles. This study sheds light on a simple method to improve the damage tolerance by fabricated dissimilar laminate of diffusion bonding.