Enhancing fatigue resistance of nanocrystalline Ni/Ni-W laminated composites

The fatigue strength of nanocrystalline Ni/Ni-W laminated composites was investigated. The results reveal that the fatigue resistance of the Ni/Ni-W laminated composites is improved compared with that of monotonic Ni. Shear banding and voiding are two modes dominating fatigue damage of the composites. A deformation map is proposed to elucidate the critical condition of the formation of shear bands and voids, as well as the transition of two damage modes. The ultrathin Ni-W layers introduced into the laminated composites hindered the crack crossing the heterogeneous interface through their local thinning and necking, and thus improved the fatigue strength.