Plastic behaviour of copper sheets subjected to a double strain-path change

Abstract

Three sequences of three strain paths have been carried out on a polycrystalline copper sheet: tension—rolling—tension with the rolling direction normal to the tensile axes; rolling—rolling—tension, the first and the second rollings being performed parallel and normal to the tensile axis, respectively; and rolling—rolling—tension, the first and the second rollings being performed normal and parallel to the tensile axis, respectively. In order to achieve a better understanding of the mechanical behaviour of the copper sheet under complex strain paths, the effects of double strain-path change on the subsequent reloading yield stress and residual uniform strain have been investigated. It is found that the mechanical behaviour after reloading depends mainly on the orientation relationship between the previous and subsequent paths and less on the order in which they have been performed. A “hard” orientation relationship between two strain paths, consecutive or not, strongly imposes the effects of the prestrain path on the subsequent behaviour.