THE EFFECTS OF SHEAR CONSTRAINTS ON THE LATTICE ROTATION OF FCC CRYSTALS IN (011) CHANNEL-DIE COMPRESSION

THE evolution of texture during channel-die compression is examined analytically for a range of crystal orientations with a (011) compression axis. The analysis considers the effects of longitudinal-transverse shear on the rotation of the crystal lattice along the alpha-fiber, with particular attention toward the evolution of Brass texture. Closed-form expressions are obtained for the lattice rotation rate in terms of the current orientation and the applied deformation. A relation between the lattice orientation and compressive strain is found for simple deformation histories. The results show that the rate of texture evolution can be enhanced or impeded by applied shear and that the lattice rotation is faster if the shear is restrained. Thus, for crystals with orientations restricted to the alpha-fiber, a stable Brass texture will develop in a full constraint Taylor model; but lattice rotation along this fiber is not predicted in a model where longitudinal-transverse shear is permitted. The results also suggest that the stress state required to deform crystals of this orientation in a Taylor model may be unrealistic.