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

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autor(en): Zhang J, Singer R
Zeitschrift: Zeitschrift für Metallkunde
Jahr der Veröffentlichung: 2002
Band: 93
Seitenbereich: 806-811
ISSN: 0044-3093
Sprache: Englisch


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.



FAU-Autoren / FAU-Herausgeber

Singer, Robert Prof. Dr.-Ing.
Lehrstuhl für Werkstoffwissenschaften (Werkstoffkunde und Technologie der Metalle)


Zitierweisen

APA:
Zhang, J., & Singer, R. (2002). Effect of hafnium on castability of directionally solidified nickel-base superalloys. Zeitschrift für Metallkunde, 93, 806-811.

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

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Zuletzt aktualisiert 2018-08-09 um 07:10