Intrinsic fracture toughness of bulk nanostructured Cu with nanoscale deformation twins

A contactless video crack opening displacement gauging system based on digital image correlation technique was established to measure the load-line displacement of miniaturized fracture toughness samples precisely. The intrinsic fracture toughness and smoothly rising R-curve of bulk dynamic plastic deformation (DPD) Cu with nanotwin bundles embedded in nano-grained matrix were measured through elastic-plastic unloading compliance method using miniaturized side-grooved compact tension specimens. Nanotwin bundles exert positive bearings on enhancing the damage tolerance of the DPD Cu. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.