Nanostructure evolution and mechanical property changes during aging of a super duplex stainless steel at 300°C
Journal article, 2015

The nanostructure evolution and the corresponding changes in mechanical properties of a super duplex stainless steel 2507 (UNS S32750) during aging at 300. °C up to 12,000. h have been investigated. Microstructural studies using transmission electron microscopy and atom probe tomography show that subtle Cr concentration fluctuations develop during aging. The amplitude of the concentration fluctuations is proportional to the hardness of the ferrite phase, and it is also proportional to the decrease in room temperature impact toughness during aging. The fracture behaviour of the alloy changes gradually from ductile to cleavage fracture, upon aging. The cracks were found to propagate through the ferrite phase, partly along deformation twin interfaces, and delamination between the austenite and ferrite phases was observed.

Duplex stainless steel

Phase separation

Atom probe tomography (APT)

Mechanical properties

Spinodal decomposition

Transmission electron microscopy (TEM)


N. Pettersson

Swerea KIMAB

S. Wessman

Swerea KIMAB

Mattias Thuvander

Chalmers, Applied Physics, Materials Microstructure

P. Hedström

Royal Institute of Technology (KTH)

J. Odqvist

Royal Institute of Technology (KTH)

R.F.A. Pettersson

Jernkontoret - The Swedish Steel Producers’ Association

S. Hertzman

Outokumpu Stainless Research Foundation

Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

0921-5093 (ISSN)

Vol. 647 241-248

Subject Categories

Metallurgy and Metallic Materials



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