Hot deformation to high strains; Microstructure, texture and flow stress behaviour

An investigation of the development of the stress-strain curve during deformation in torsion has been carried out. A fall in the flow stress of about 20% was found from the peak of the stress-strain curve to a second steady state. To investigate the origin of the fall in the flow stress the change in texture and microstructure during deformation was followed. The texture was found to change from a close to random texture at the peak of the stress-strain curve to a texture mainly consisting of the components {001}< 110 > and {112}< 110 > at the second steady state strain. A fall in the stress of 5%-7% could hence be ascribed to the change in texture. The subgrain size was found to increase by about 20% corresponding to a fall in the flow stress of 10%.