An investigation of grain-boundary embrittlement in Fe−P,Fe−P−S,and Fe−Sb−S alloys

Grain-boundary embrittlement of pure iron due to phosphorous, antimony and sulfur is studied using fracture appearance transition temperature measurements and Auger electron emission spectroscopy chemical analysis of fractured surfaces. Phosphorus and sulfur are found to segregate to grain boundaries in the entire ferrite range. Segregation to grain boundaries of these elements in the austenite appears to be negligible. It is shown that the segregation of these elements to grain boundaries in iron does not conform to the Gibb's equilibrium segregation model. Sulfur appears to be a more severe embrittler of iron than does phosphorous. P. V. RAMASUBRAMANIAN formerly was Graduate Research Assistant, University of Minnesota. D. F. STEIN, formerly Professor, Department of Mechanical and Chemical Engineering, University of Minnesota