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.