Precipitation behavior of gamma′ precipitates in the fusion zone of TIG welded ATI 718Plus®
2016 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 87, no 9-12, 2721-2729 p.Article in journal (Refereed) PublishedText
The precipitation behavior of the main strengthening phase, γ′ precipitates, in ATI 718Plus® superalloy after Tungsten Inert Gas (TIG) welding and postweld heat treatments has been studied. In contrast to electron beam welding, where no γ′ precipitates are reported to form in the as-welded condition, analytical transmission electron microscopy study in this work revealed the formation of γ′ precipitates after the TIG welding, albeit in a non-uniform distribution manner. This is attributable to a more extensive elemental microsegregation that occurred into the interdendritic liquid and slower cooling rate during the TIG welding, which also induced the formation of interdendritic Nb-rich Laves phase particles and MC-type carbides. Theoretical calculations were performed to study the influence of Nb microsegregation, on both the kinetics and extent of γ′ precipitation, and the results agree with experimental observations. It is found that the precipitation kinetics, and not the extent of γ′ precipitate formation in the fusion zone, during postweld heat treatments is affected by the micro-segregation of Nb that produced Laves phase particles during the weld solidification.
Place, publisher, year, edition, pages
2016. Vol. 87, no 9-12, 2721-2729 p.
Superalloy, Welding ATI, 718+
Manufacturing, Surface and Joining Technology
Research subject ENGINEERING, Manufacturing and materials engineering
IdentifiersURN: urn:nbn:se:hv:diva-9308DOI: 10.1007/s00170-016-8642-0ISI: 000388988300023ScopusID: 2-s2.0-84962018767OAI: oai:DiVA.org:hv-9308DiVA: diva2:919093
First online: 02 April 20162016-04-132016-04-112017-01-11Bibliographically approved