Shear loading of FCC/BCC Cu/Nb nanolaminates studied by in situ X-ray micro-diffraction

Abstract

Face-centered cubic/body centered cubic (FCC/BCC) nanolaminates prepared by Accumulative Roll Bonding (ARB) have been extensively studied because of their unique mechanical properties. Recently, micro-beam bending experiments, performed on Cu/Nb ARB samples, have shown an anisotropic interface sliding behavior linked to the strong in-plane texture. To test interface sliding on a macroscale we have developed a shear test based upon a specific sample geometry and on in situ tensile loading on an X-ray synchrotron beamline. As received nanolaminate samples exhibit a very anisotropic crystallographic texture as expected from the fabrication process. In situ X-ray diffraction in the sheared zone during mechanical loading yields strains in Cu and Nb. Early brittle failure prevents investigating further the sliding at interfaces. This is probably caused by crack initiation from the inner surfaces of the notches used to induce shear.