Trace elements in superalloys–an overview

Abstract

This paper commences with a brief description of superalloys and their applications. Trace elements which may be present are classified, and their effects, adverse or beneficial, are briefly summarized. More detailed discussion of effects and mechanisms will be provided in the other papers in this issue. Some elements may be beneficial in small concentrations, but harmful in larger ones. In many cases, the effects of individual elements have been sufficiently quantified to allow specification limits to be set, but further work is required on the effects of different elemental combinations, on analysis at low concentrations, and on the mechanisms by which some trace element effects operate. With respect to the control of trace elements, it is necessary to specify not only the purity of the metallic raw materials, but also the purity of consumable manufacturing-process materials.