Orientation dependence of variant selection and intersection reactions of<i>ϵ</i>martensite in a high-manganese austenitic steel

Abstract

The orientation dependence of ϵ martensite during loading of a polycrystalline austenitic Fe-30Mn-4Si-2Al steel has been investigated by electron backscatter diffraction, emphasising the variant selection rule and plate–plate intersection reactions. Two types of plate–plate intersection reactions, which are characterised by incident shear direction of either 30° or 90° with respect to the intersection axis, were found in the grains along the [001]–[111] directions and [001]–[101] directions, respectively. In the intersecting volume of the latter type reaction, a γ phase rotated 90° from the austenite matrix along the ⟨011⟩ zone axis of the intersecting ϵ plates, which was theoretically predicted by Sleeswyk [A.W. Sleeswyk, Philos. Mag. 7 (1962) p.1597], has been experimentally observed for the first time.