Thermodynamics of phosphorus grain boundary segregation in polycrystalline low-alloy steels

18Phosphorus grain boundary segregation in three polycrystalline Cr-Mo-V low-alloy steels was investigated using Auger electron spectroscopy and thermodynamic calculations. Obtained data on polycrystals fit very well with the recently reported linear relationship between enthalpy and entropy of phosphorus segregation at individual grain boundaries of alpha -iron found in bicrystals of an Fe-Si alloy. Different crystallography seems to be responsible for the scatter of the values of segregation enthalpy for individual low-alloy steels.