Micro shear bands in cold-rolled austenitic stainless steel

Shear bands (SBs) in cold-rolled austenitic stainless steel 310S have been investigated by using transmission electron microscopy (TEM). Shear Bands a ppear in the region of twin-matrix lamellae which have already developed at moderate strain. Inside the shear band, fine grains are observed, and the shape of each grain is somewhat elongated along the shear direction. These features found in 310S are similar to those observed in materials with very low stacking fault energy such as alpha-brass. Selected area diffraction p atterns obtained from a SE reveals that local orientations inside the SE ar e distributed between those in the matrix and the twinning region. Using da rk field images of the SE, it is shown that some of the misorientations of neighboring grains in the SE reach nearly 20 degrees. Based on these observ ations, the formation mechanism of SBs is discussed.