Three-dimensional shear-strain patterns induced by high-pressure torsion and their impact on hardness evolution

The shear strain imposed on austenite/ferrite duplex stainless steel discs at different stages of high-pressure torsion (HPT) processing was imaged in plan-view and cross-section using optical microscopy and scanning electron microscopy. The effect of the shear strain was correlated to the hardness evolution of the discs. The shear-strain patterns are complex and are different on the top and bottom surfaces of the discs. A double-swirl pattern...