Structural and Mechanical Behaviour of Severe Plastically Deformed OFE Copper Processed by Constrained Groove Pressing Technique

Abstract

Oxygen free electrolytic (OFE) grade copper sheets (5mm thick) are severe plastically deformed by constrained groove pressing technique (CGP) at room temperature up to three passes thereby imparting a total plastic strain of 3.48 throughout the sheet material. The revelation of significant grain refinement investigated by light microscopy in constrained groove pressed sheets markedly signifies the ability of CGP technique for processing fine grained sheet materials. Relatively higher grain refinement rates are observed during initial passes. Deformation homogeneity evaluated from Vickers microhardness measurements indicated inhomogeneous deformation behaviour during early stages of straining; however enhancement in deformation homogeneity is observed later. CGP processed sheets subjected to room temperature tensile tests showed significant increase in strength associated with drop in ductility. Marginal gain in ductility coupled with slight decrease in strength attributed to the dominance of dislocation recovery is observed after third pass.