Shear and multiaxial responses of oxygen free high conductivity (OFHC) copper over wide range of strain-rates and temperatures and constitutive modeling

In this paper, the experimental response of oxygen free high conductivity (OFHC) copper under multiaxial loading conditions is presented, along with quasi-static and dynamic response under uniaxial compression loading. The multiaxial experiments were performed under non-proportional loading conditions, where the sample was subjected to uniaxial loading for a predetermined strain followed by biaxial loading. These experimental results provide a comprehensive data set for constitutive modeling of the material response at finite strains, over a wide range of strain-rates and temperatures. The observed strain-rate and temperature dependent responses under uniaxial loading are shown to correlate closely using the Khan-Huang-Liang (KHL) constitutive model; the model is shown to be in close agreement with other published experimental results [Khan, A.S., Liang, R., 1999. Behavior of three BCC metal over a wide range of strain rates and temperatures. International journal of Plasticity 15, 1089-1109; Nemat-Nasser, S., Li, Y., 1998. Flow stress of F.C.C polycrystals with applications to OFHC Cu. Acta Materialia 46(2). 565-577]. This constitutive model is further demonstrated to predict the observed material response accurately, using the material constants determined from uniaxial loading results during proportional and non-proportional loading experiments. The micro-texture characterization of as-extruded, annealed and deformed samples was performed to investigate the effect of temperature and strain-rate on texture evolution of OFHC copper. Grain average misorientation (GAM) was used to reveal the deformation heterogeneity and orientation gradients in deformed samples. (c) 2012 Elsevier Ltd. All rights reserved.