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 appear 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 α-brass. Selected area diffraction patterns obtained from a SB reveals that local orientations inside the SB are distributed between those in the matrix and the twinning region. Using dark field images of the SB, it is shown that some of the misorientations of neighboring grains in the SB reach nearly 20 degrees. Based on these observations, the formation mechanism of SBs is discussed.