Abstract
The present study investigates the roles of layer thickness and loading direction on the fatigue and fracture behavior of Cu/Nb multilayered nanolaminates (MNLs) produced by accumulative roll-bonding (ARB). Three MNL materials with layer thicknesses ranging from 4.4 mu m to 44 nm were investigated. Uniaxial tensile tests revealed a monotonic increase in yield strength with finer layer thickness and following a Hall-Petch relationship while the ductility was decreasing. The in-plane anisotropy between the rolling and transverse direction was attributed to the crystallographic texture on the basis of crystal plasticity simulations. Four- point bending fatigue tests demonstrated a notable increase in fatigue strength and limit with decreasing layer thickness with limited anisotropy in terms of loading direction. Interface delamination and crack deflection were identified as key mechanisms in fatigue crack propagation, contributing to improved fatigue performance by dissipating strain energy. Fracture toughness tests revealed that finer layers enhance toughness potentially due to increased interface sliding and higher interface strength.