Interfacial segregation and cosegregation behaviour in a nickel-base alloy 718

The Auger analyses provided clear evidence of sulfur and phosphorus segregation to grain boundaries and carbide/matrix interfaces. The degree of segregation was different for the two elements. Sulfur was preferentially segregated at the carbide/matrix interface while phosphorus was mainly distributed on grain boundaries. It was also found that metal elements, such as Mo and Nb also segregated to grain boundaries, these grain boundary segregation results show the existence of the attractive interactions of phosphorus with metal elements of Mo and Nb at grain boundaries, especially the co-segregation of Mo–P. It did not find any interaction of sulphur with metal elements at grain boundaries.