Theory of High-Temperature Type Work-Hardening of Body-Centred Cubic Metals

Abstract

A dislocation arrangement in cell boundaries is set up on the basis of experimental evidences that cell boundaries deviate from slip plane by a few degrees. The internal stresses associated with this cell structure are determined self-consistently from the dislocation arrangement in cell boundaries and the motion of secondary dislocations through the cell boundaries. In this model, the primary slip system activates discontinuously in one layer of the cell structure and it forms slip lines with finite shear strain. If no dislocation annihilation occurs in cell boundaries, the flow stress increases approximately linearly with strain. The decrease of work-hardening rate in the later stage of deformation is due to the annihilation of closely spaced edge dislocation dipoles in cell boundaries by conservative climb.