STRESS ENHANCED GRAIN-BOUNDARY SEGREGATION OF IMPURITY ELEMENTS IN A LOW-ALLOY STEEL

Grain boundary segregation isotherms determined by Auger electron spectroscopy (AES) have been employed to elucidate the effect of applied stress on grain boundary chemistry of a low alloy 2.6 NiCrMoV steel. A comparison of grain boundary segregation isotherms of low alloy steel isothermally heat treated at 773 K under constant load and unstressed conditions strongly indicates that stress accelerates grain boundary segregation of impurity elements N, P and S. This enhancement of grain boundary coverage of elements N, P and S is explained in terms of structure of grain boundary, described commonly as an array of linked deltahedra containing holes of varying size and shape. © 1990.