Non-equilibrium grain boundary segregation of phosphorus under a high applied tensile stress in a 2.25Cr1Mo steel

Grain boundary segregation of phosphorus under a 350 MPa tensile stress at 520 °C in a 0.025 wt.% P-doped 2.25Cr1Mo steel, which has already been thermally equilibrated, is examined using Auger electron spectroscopy. The segregation of phosphorus during stress ageing has a non-equilibrium characteristic, which has two phosphorus segregation peaks over its equilibrium segregation level, one of which is mainly due to the vacancy-phosphorus complex effect and the other due to the diffusional creep effect.