Tensile and creep-rupture response of additively manufactured nickel-based superalloy CM247LC

Tensile and creep rupture properties of crack-free CM247LC alloy, processed via laser powder bed fusion, have been characterised in this work at temperatures up to 1000 & DEG;C. The subject alloy matches or even exceeds the tensile performance of its directionally solidified counterpart up to 700 & DEG;C, beyond which both the strength and ductility drop off relatively rapidly with increasing temperature. It was found that the agglomeration of discrete carbides - that essentially pin the grain boundaries - facilitate the nucleation, linking and propagation of micro-cracks along the adjacent grain boundaries at elevated temperatures. Relatively short-term creep-rupture tests conducted at 800 & DEG;C show the need for greatly improving the microstructure of this alloy to compete with its di-rectionally solidified or conventionally cast counterparts, especially considering that this material finds extensive application up to & SIM;950 & DEG;C in turbomachinery components. Increasing the grain size, incorporating grain boundary engineering concepts and a better understanding of carbide/ ������' precipitate evolutionary characteristics can greatly help to improve the material's suboptimal creep response.