Enhancing fatigue strength of high-strength ultrafine-scale Cu/Ni laminated composites

Fatigue strength of the Cu/Ni laminated composites with different thickness ratios of the Ni layer to the Cu layer was investigated. The result reveals that the Cu/Ni laminated composite with the thickness ratio of the Ni layer to the Cu layer of 9.0:1 not only has an ultrahigh strength (1361.80 MPa), but also is of a relatively high fatigue ratio approaching to 0.30 compared with ultrafine-grained and nanocrystalline Ni. The introduction of the ultrathin Cu layers into the ultrafine-scale Ni leads to alternate variation of local delamination and crack deflection crossing the layers in the Cu/Ni laminated composites subjected to fatigue loading, maximizing the cracking resistances in spatial directions.