Microstructural characterisation and development of cast Ni-based alloys for high temperature power plant

Ni-based alloys must be considered for specific components in advanced ultra supercritical (A-USC) plants in order to cope with the conditions required for high efficiency energy conversion plants at temperatures of ~760°C and pressures of 35 MPa. For large, complex components such as valves and casings, casting is the main route for their commercial production. Haynes(H) 282 and Inconel (IN) 740H are two possible candidate alloys, however, both of these alloys were originally developed for wrought applications rather than cast applications, and consequently there are limited data about the cast microstructure and its associated challenges for these alloys. This project has focused on large castings manufactured from H282 and IN740H and aims to produce comprehensive data for their cast versions, including their microstructure and associated issues, and this has then led to consideration of the development of a new composition Ni-based alloy suitable for the manufacture of large castings.  [Continues.]