Sympathetic nucleation of austenite in a Fe–22Cr–5Ni duplex stainless steel

In a Fe–22Cr–5Ni duplex stainless steel, δ-ferrite in a very high supersaturated solid solution state was found to promote the formation of the intragranularly nucleated austenite. Transmission electron microscopy revealed that, after the initial nucleation events for intragranularly nucleated austenite, the subsequent small particle of austenite could form sympathetically at the broad face of the prior austenite grain. The orientation relationship between adjacent grains of sympathetically nucleated austenite has been investigated.