SYMPOSIA PAPER Published: 01 January 2001

Grain Boundary Phosphorus Segregation Under Irradiation and Thermal Aging and Its Effect on the Ductile-to-Brittle Transition


Embrittlement of low-alloy steel components used in the nuclear power industry is classified into hardening embrittlement and non-hardening embrittlement. Hardening embrittlement stems from precipitation of carbides or copper-rich compounds. Non-hardening embrittlement results mainly from grain boundary segregation of phosphorus. To examine the non-hardening embrittlement in 2.25Cr 1Mo steel, phosphorus intergranular segregation in samples subjected to neutron irradiation and thermal aging at 270°C and 400°C is determined by modelling and transmission electron microscopy. The ductile-to-brittle transition temperature for the steel is determined by means of small punch testing with 3 mm diameter disc specimens. It is indicated that there is a reasonable agreement between the behavior of intergranular phosphorus segregation and shifts in the ductile-to-brittle transition temperature. Measured and predicted phosphorus intergranular segregation in a range of pressure vessel steels is also discussed.

Author Information

Song, S
IPTME, Loughborough University, Loughborough, Leics, UK
Faulkner, RG
IPTME, Loughborough University, Loughborough, Leics, UK
Flewitt, PEJ
BNFL Magnox Generation, Berkeley Center, Berkeley, Glos, UK
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Developed by Committee: E10
Pages: 189–203
DOI: 10.1520/STP10533S
ISBN-EB: 978-0-8031-5454-4
ISBN-13: 978-0-8031-2878-1