Intermetallic Phase Precipitation in Duplex Stainless Steels during High Temperature Exposition
The intermetallic phase precipitation, mainly sigma () and chi () phases, was studied in a comparative manner in two stainless duplex steels: a duplex type UNS S31803 and a superduplex type UNS S32520. The -phase precipitated at ferrite/ferrite grain boundaries prior to the -phase precipitation, which occurred preferentially at ferrite/austenite interfaces and at ferrite/ferrite grain boundaries. The -phase precipitation is a eutectoid type reaction of ferrite, leading to -phase and austenite (γ). The -phase precipitated at lower temperatures and in smaller amounts than sigma. The -phase is metastable in the studied steels and was consumed during the -phase precipitation.
Luís Guerra ROSA and Fernanda MARGARIDO
D.M. Escriba et al., "Intermetallic Phase Precipitation in Duplex Stainless Steels during High Temperature Exposition", Materials Science Forum, Vols. 636-637, pp. 478-484, 2010