Abstract
Grain boundary segregation of phosphorus and silicon was investigated in an Fe-2.65Si-0.028P alloy. Polycrystalline samples of various grain sizes and grain boundary compositions were fractured by impact in vacuum. Chemical compositions of grain boundaries were analysed by Auger electron spectroscopy. Scanning electron microscopy was used to observe fracture surfaces and to determine portions of intergranular fracture. The aim was to characterise the influence of the grain size and the grain boundary concentrations of phosphorus and silicon on the character of fracture surface. The portion of intergranular fracture was found to correlate positively with the grain size and the amount of grain boundary segregation.

Key words
iron alloys, interface segregation, intergranular brittleness, Auger electron spectroscopy, scanning electron microscopy

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