Crystallography of Widmanstatten austenite in duplex stainless steel weld metal

Two kinds of austenite grow from delta-ferrite during the cooling of the duplex stainless steel weld deposits studied here, Widmanstatten plates and allotriomorphs which precipitate at delta-delta grain boundaries. It is found using microtexture measurements that the preferred crystallographic orientation of the Widmanstatten austenite can be estimated using established theory if it is assumed that there is an interaction between external stress and the growing plates. It is also demonstrated that the Widmanstatten and allotriomorphic forms of austenite may not be identically oriented even when the former appears to originate from the latter; this may be a consequence of differences in the transformation mechanisms of these two forms of austenite.