Atom probe and transmission electron microscopy study of reverted duplex stainless steels

Duplex stainless steels are subject to embrittlement after long term aging at temperatures below 500-degrees-C. This embrittlement is usually attributed to the alpha-alpha' phase separation occurring in the ferrite, though the role of G-phase particles, when present, may not be negligible. In order to try to restore their mechanical properties to that of the as-quenched conditions, some specimens were reannealed above the Fe-Cr miscibility gap. The mechanical effect of various reannealing treatments is reported, and correlated with transmission electron microscopy and atom probe field ion microscopy microstructural investigations.