EBSD characterization of dynamic shear band regions in pre-shocked and as-received 304 stainless steels

The microstructure and texture variations near adiabatic shear localization regions in as-received and pre-shocked 304 stainless steels were investigated using electron backscatter diffraction (EBSD). Shear bands were developed in both steels during a forced dynamic shear deformation produced on a split-Hopkinson pressure bar. EBSD examination revealed large intragranular misorientation gradients toward the shear bands. Taylor factor and misorientation analyses were applied to explain deformation characteristics. Shear-induced deformation structure was observed to be sensitive to both initial microstructure and local orientation. Comparison of as-received and pre-shocked steels indicated that the pre-shocked condition yielded sharper shear band boundaries but moderate misorientation gradients, while the as-received condition led to substantial misorientation adjacent to the band. Shear-induced texture evolution generally resulted in the reorientation of 〈1 1 0〉 toward the shear direction for both cases. Grains with slip systems favorably oriented with respect to the applied shear path displayed less intragranular misorientation development compared to unfavorably oriented grains.