Effect of temperature–strain-rate conditions of deformation on structure formation in commercially pure copper deformed in Bridgman anvils

Abstract

Commercially pure copper (99.9 wt % Cu) subjected to high-pressure torsion at room temperature is investigated. A relation between the copper structure and temperature–strain-rate conditions has been established. It has been shown that impurity dragging prevents grain growth during postdynamic recrystallization. This has allowed us to determine the conditions under which either the hardening of the deformed material, which is accompanied by a continuous increase in the hardness and structural refinement, or the dynamic recrystallization resulting in the stabilization of the hardness and the average grain size predominantly occurs in commercial-purity copper compared to high-purity copper (99.99 wt %). It has been shown that, under the hardening conditions, the structure of the investigated copper is determined by the true strain, whereas under dynamic recrystallization conditions, by temperature–compensated strain rate.