Review of microstructure-property relationships in cast & wrought Ni-based superalloys with boron, carbon, and zirconium microalloying additions

F. Theska, W. F. Tse, B. Schulz, R. Buerstmayr, S. R. Street, M. Lison-Pick, S. Primig
Advanced Engineering Materials (2022) 2201514. (OPEN ACCESS)

Cast & wrought Ni-based superalloys are engineering materials for high-temperature components resisting the harsh environments in aircraft engines and gas turbines. Improvements to efficiency require the highest alloyed Ni-based superalloy grades with superior high-temperature strength. This makes cast & wrought processing more challenging due to macro-segregation, higher flow stress and cracking. B, C, and Zr are microalloying additions usually added to optimize high-temperature strength and creep properties via grain boundary segregation and precipitation. However, their detailed roles during cast & wrought processing of Ni-based superalloys are complex and a comprehensive review was missing.

We provide a systematic review to advance the current understanding of B, C, and Zr individually and in combination during (re-)melting, wrought processing, and in-service. Addressing the gaps in knowledge that are identified in this review will allow a more complete understanding of processing-microstructure-property relationships in advanced cast & wrought Ni-based superalloys.