Plastic deformation mechanism of pure copper at low homologous temperatures

Abstract

Plastic deformation mechanism of pure metals at low homologous temperatures is attributed to the motion of dislocations and their interactions with each other or other kinds of obstacles. Physically based modeling of deformation mechanism is generally considered as thermally activated motion of dislocations past obstacles and structural evolution of the obstacles. In this study, stress rate change experiments, which give rapid stress changes, are conducted using pure copper at room temperature. Incremental method is employed in the numerical simulation of above modeling. Excellent agreement is observed in the comparison between experimental data and numerical calculations, especially on the very abrupt change in strain rate at the stress rate change point. Sensitivity analyses are also performed to better understand both flow kinetics and structural evolution law. Simple kinetic model such as the regular distributed rectangular obstacle is adequate enough. Obstacle structure is strongly influenced by the dislocation annihilation processes.