Effect of Microstructure on the Tensile and Fatigue Behavior of an Accumulative Roll Bonded Cu/Nb Laminate Material

The tensile and fatigue behavior of an accumulative roll bonded Cu/Nb laminate material was investigated experimentally and numerically by means of crystal plasticity finite element simulations. The material exhibited a slight anisotropy in tensile strength and ductility when deformed either along the rolling or transverse direction. This anisotropy was attributed to the strong crystallographic texture of the Nb phase resulting in a higher stress and strain partitioning when the loading direction was along the transverse direction. Four-point bending fatigue tests were then conducted and revealed apparently higher fatigue life when the tensile axis was aligned with the rolling direction which was attributed to anisotropic texture in the Nb layers leading to longer crack incubation period and lower crack growth rate. The analysis of a fatigue indicator parameter based on the Tanaka-Mura model and the Fatemi-Socie criterion confirmed the longer nucleation period for the rolling direction specimen.