Integrated experimental and computational studies of deformation of single crystal copper at high strain rates
S Rawat and S Chandra and VM Chavan and S Sharma and M Warrier and S Chaturvedi and RJ Patel, JOURNAL OF APPLIED PHYSICS, 116, 213507 (2014).
Quasi-static (0.0033 s(-1)) and dynamic (10(3) s(-1)) compression experiments were performed on single crystal copper along < 100 > and < 110 > directions and best-fit parameters for the Johnson-Cook (JC) material model, which is an important input to hydrodynamic simulations for shock induced fracture, have been obtained. The deformation of single crystal copper along the < 110 > direction showed high yield strength, more strain hardening, and less strain rate sensitivity as compared to the < 100 > direction. Although the JC model at the macro- scale is easy to apply and describes a general response of material deformation, it lacks physical mechanisms that describe the influence of texture and initial orientation on the material response. Hence, a crystal plasticity model based on the theory of thermally activated motion of dislocations was used at the meso-scale, in which the evolution equations permit one to study and quantify the influence of initial orientation on the material response. Hardening parameters of the crystal plasticity model show less strain rate sensitivity along the < 110 > orientation as compared to the < 100 > orientation, as also shown by the JC model. Since the deformation process is inherently multiscale in nature, the shape changes observed in the experiments due to loading along < 100 > and < 110 > directions are also validated by molecular dynamics simulations at the nano-scale. (C) 2014 AIP Publishing LLC.
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