Effect of hafnium on the castability of directionally solidified nickel-base superalloys

Zhang J, Singer R (2002)


Publication Language: English

Publication Type: Journal article

Publication year: 2002

Journal

Book Volume: 93

Pages Range: 806-811

DOI: 10.3139/146.020806

Abstract

The effect of Hf additions on the solidification characteristics and castability of the Ni-base superalloy IN792 has been studied. A quenching technique was employed to freeze-in the microstructure during solidification. The crack length in tube-shaped demonstration castings was evaluated. Hf additions were found to reduce the hot-tearing susceptibility significantly. Hf also caused a more gradual decrease of the liquid fraction with temperature in the last stages of solidification, which was observed to improve castability in other alloys previously and which can be correlated with lower strains and strain rates in the vulnerable period where hot tears form. It was also found that the γ/γ′ rosette structure, often referred to as γ/γ′ eutectic in the literature, actually forms by a discontinuous precipitation mechanism from the solid. The amount of γ/γ′ observed in the interdendritic area, therefore, does not reflect the amount of remaining liquid in the last stages of solidification.

Authors with CRIS profile

How to cite

APA:

Zhang, J., & Singer, R. (2002). Effect of hafnium on the castability of directionally solidified nickel-base superalloys. Zeitschrift für Metallkunde, 93, 806-811. https://dx.doi.org/10.3139/146.020806

MLA:

Zhang, Jian, and Robert Singer. "Effect of hafnium on the castability of directionally solidified nickel-base superalloys." Zeitschrift für Metallkunde 93 (2002): 806-811.

BibTeX: Download