Cluster formation in in-service thermally aged pressurizer welds
Journal article, 2018

Thermal aging of reactor pressure vessel steel welds at elevated temperatures may affect the ductile-to-brittle transition temperature. In this study, unique weld material from a pressurizer, with a composition similar to that of the reactor pressure vessel, that has been in operation for 28 years at 345 °C is examined. Despite the relatively low temperature, the weld becomes hardened during operation. This is attributed to nanometre sized Cu-rich clusters, mainly located at Mo- and C-enriched dislocation lines and on boundaries. The welds have been characterized using atom probe tomography, and the characteristics of the precipitates/clusters is related to the hardness increase, giving the best agreement for the Russell-Brown model.

RPV steel

Thermal aging

Atom probe tomography



Kristina Lindgren

Chalmers, Physics, Materials Microstructure

M. Boasen

Royal Institute of Technology (KTH)

Krystyna Marta Stiller

Chalmers, Physics, Materials Microstructure

P. Efsing

Royal Institute of Technology (KTH)

Ringhals AB

Mattias Thuvander

Chalmers, Physics, Materials Microstructure

Journal of Nuclear Materials

0022-3115 (ISSN)

Vol. 504 23-28

Subject Categories


Manufacturing, Surface and Joining Technology

Metallurgy and Metallic Materials



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