Intermediate-temperature embrittlement induced by non-equilibrium grain-boundary segregation of sulfur in Ni–Cr–Fe alloy

Abstract

Intermediate-temperature embrittlement (ITE) for a Ni–Cr–Fe alloy has been experimentally studied by Auger electron spectroscopy and elevated-temperature tension tests. Results show both the grain boundary concentration of sulfur and the degree of embrittlement reach maxima at 500°C. The peak of the grain boundary concentration of sulfur during aging at 500°C occurs at about 20 min, which is close to the holding time prior to the start of tension at the test temperature. It can be concluded from these results that ITE of this alloy is induced by non-equilibrium grain-boundary segregation of sulfur.