Fe and Cr phase separation in super and hyper duplex stainless steel plates and welds after very short aging times
Journal article, 2021

Fe and Cr phase separation in ferrite, causing 475 °C-embrittlement, was studied after very short aging times in super duplex stainless steel (SDSS) and hyper duplex stainless steel (HDSS) plates and welds. Atom probe tomography showed that hot-rolled SDSS, experiencing significant metal working, had faster kinetics of phase separations compared to the SDSS and HDSS welds after 5 min aging at 475 °C. The surface of the 33-mm SDSS plate had faster Fe and Cr phase separation and larger toughness drop. A higher density of dislocations next to the austenite phase boundary in ferrite, detected by electron channeling contrast, can promote the phase separation at the surface of the plate with lower austenite spacing. The toughness dropped in HDSS welds after aging, but SDSS welds maintained their toughness. An inverse simulation method considering an initial sinusoidal nanometric Cr and Fe fluctuation showed that Ni increases the interdiffusion of Cr in the system, resulting a higher degree of phase separation in SDSS welds than the HDSS weld. Within the composition range of the studied SDSS and HDSS materials, the processing influences the Fe and Cr phase separation more than the variation in composition during short aging or typical fabrication times.

Welding, hot rolling

Atom probe tomography

Spinodal decomposition


Duplex stainless steels


Vahid A Hosseini

University West

Mattias Thuvander

Chalmers, Physics, Microstructure Physics

Kristina Lindgren

Chalmers, Physics, Microstructure Physics

James Oliver

Outokumpu AB

Nicklas Folkeson


Daniel Gonzalez


Leif Karlsson

University West

Materials and Design

0264-1275 (ISSN) 1873-4197 (eISSN)

Vol. 210 110055

Subject Categories

Physical Chemistry

Manufacturing, Surface and Joining Technology

Metallurgy and Metallic Materials


Chalmers Materials Analysis Laboratory



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Latest update

9/3/2021 2