Analysis of temperature distribution in shell mould during thin-wall superalloy casting and its effect on the resultant microstructure

Appropriate lost-wax casting parameters lead to the creation of coarse grained structure, desired for high-temperature service applications. As a result of non-equilibrium solidification, substantially large chemical inhomogeneities in the dendrite core and interdendritic spaces are formed. Interdendritic spaces are occupied by constituents formed as a consequence of segregation of alloying elements, namely eutectic islands γ/γ′, borides, carbides, and an intermetallic compound of Ni and Zr. Dendrite cores consist of cubic-shaped γ′ precipitates surrounded by Ni-rich γ channels. Low lattice misfit influences cubic morphology of γ′ precipitates, which is favourable for jet engine application because it can guarantee good creep resistance.