A constitutive model for fcc crystals with application to polycrystalline OFHC copper

Based on the results of a series of experiments on commercially pure OFHC copper (an fcc polycrystal), a physically based, rate- and temperature-dependent constitutive model is proposed for fcc single crystals. Using this constitutive model and the Taylor averaging method, numerical calculations are performed to simulate the experimental results for polycrystalline OFHC copper. The model calculation is based on a new efficient algorithm which has been successfully used to simulate the flow stress of polycrystalline tantalum over broad ranges of temperature, strain rate, and strain (Nemat-Nasser, S., Okinaka, T., Ni, L., 1998. J. Mech. Phys. Solids 46, 1009). The model effectively simulates a large body of experimental data, over a broad range of strain rates (0.001–8000 s⁻¹), and temperatures (77–1096 K), with strains close to 100%. Few adjustable constitutive parameters of the model are fixed at the outset for a given material. All other involved constitutive parameters are estimated based on the crystal structure and the physics of the plastic flow.