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Microstructural evolution in the HAZ of Inconel 718 and correlation with the hot ductility testThe nickel-base alloy 718 was evaluated to study the role of preweld heat treatment in reducing or eliminating heat-affected zone hot cracking. Three heat treatments were studied using the Gleeble hot ductility test. A modified hot ductility test was also used to follow the evolution of microstructure during simulated welding thermal cycles. The microstructural evolution was correlated with the hot ductility data in order to evaluate the mechanism of hot cracking in alloy 718. The correlation of hot ductility with microstructure showed that recrystallization, grain growth, and dissolution of precipitates did not in themselves cause any loss of ductility during cooling. Ductility loss during cooling was not initiated until the constitutional liquation of NbC particles was observed in the microstructure. Laves-type phases were found precipitated in the solidified grain boundaries but were not found to correlate with any ductility loss parameter. Mechanisms are reviewed which help to explain how heat treatment controls the hot crack susceptibility of alloy 718 as measured in the hot ductility test.
Document ID
19840032512
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Thompson, R. G.
(Alabama, University Birmingham, AL, United States)
Genculu, S.
(Alabama Univ. Birmingham, AL, United States)
Date Acquired
August 12, 2013
Publication Date
December 1, 1983
Publication Information
Publication: Welding Journal, Research Supplement
Volume: 62
ISSN: 0043-2296
Subject Category
Metallic Materials
Accession Number
84A15299
Funding Number(s)
CONTRACT_GRANT: NAS8-34962
Distribution Limits
Public
Copyright
Other

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