Shear band formation in heavily cold rolled 70-30 brass

Blocks of 70 μm grain size 70-30 brass have been cold rolled up to a strain of 2.4. Polished parallelepiped samples have been prepared from the cold rolled strips and deformed in plane strain in a well-lubricated channel die. Three specimen orientations have been studied. Optical metallography has been used to determine the critical strain for the onset of shear banding and the angle which the shear bands make with the compression plane in the channel die. The strain at which shear bands form and the angle which they make with the compression plane depend upon the specimen orientation. The stress-strain curves show two distinct work hardening stages. Shear bands form under a positive rate of work hardening.