Trace element effects on ductility and fracture of Ni-Cr-Ce alloys

The effect of trace additions of Ce, ranging from Oto 180 at. ppm, on the tensile behavior of a Ni-20Cr alloy is presented. For alloys without Ce a transition from ductile transgranular to brittle intergranular fracture mode is observed at high temperatures and for low strain-rate tests. Additions of Ce suppress this transition with a resulting increase in ductility. Maximum effects are observed for temperature and strain rate values where fracture in Ce-free alloys occursvia grain boundary cavitation. The reduced cavitation rate of Ce-containing alloys is suggested to be the result of an increase in both interfacial energy and grain boundary mobility. Formerly Graduate Assistant, Department of Mechanics and Materials Science, Rutgers