High strain plane-strain deformation of 70-30 brass in a channel die

Parallel-piped samples of 90 and 4 μm grain size 70-30 brass have been deformed in plane-strain in a channel die up to a true strain of 2.3. Optical and electron metallography and X-ray diffraction have been used to determine the development of microstructure and texture with strain. The stress-strain data have been obtained by measuring the specimen dimensions and the load after each increment of 0.1 true strain. At low strains 70-30 brass deforms mainly by slip and at slightly higher strains by a combination of slip and twinning. At medium strains shear bands form. The average angle which they make with the compression plane and also their density increases with strain. The strain at which they form and their angle is different for the two grain sizes examined. The stress-strain curves show three distinct hardening stages. At low and high strains the rate of work hardening is high, while at medium strains the rate is low. Shear bands form when the rate of work hardening is low but positive and continue to form at high strains under a high rate of work hardening.