Effects of trace elements on mechanical properties of superalloys

Abstract

AbstractA review is given of the range of properties of superalloys that can be affected by trace elements and their dependence on various solutes showing the different response of a given alloy to different solutes, the different sensitivities of different alloys to the same solute, and the importance of both microstructural form and mechanical-test conditions. The main emphasis is on understanding and modelling the mechanisms by which trace elements can influence mechanical properties significantly. Trace elements at ppm concentrations are only likely to be effective with respect to mechanical behaviour if there is a mechanism leading to local enrichment. The various means of achieving this are considered including different types of segregation and the formation of precipitate particles. The factors leading to segregation of solute to, and the embrittlement of, grain boundaries are considered. Guidelines evolved to identify embrittling species in ferrous alloys are modified to predict those most likely...