Effect of delta phase on the hot deformation behaviour and microstructural evolution of inconel 718

Himanshu M. Lalvani, Martin A. Rist, Jeffery W. Brooks

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In order to investigate the influence of δ-phase precipitation during high temperature forging of Inconel 718, hot axi-symmetric compression tests have been performed on specimens with two distinct initial microstructures: i) as-received material containing a dense population of δ precipates at grain boundaries and along intragranular slip planes, and ii) material solution-treated to dissolve the δ phase. Results indicate that the presence of δ leads to a slight increase in peak stress and a proportionately greater post-peak reduction in flow stress, as compared to solutiontreated material. For both types of microstructure flow softening is associated with grain refinement, but in different ways: in δ-free material conventional dynamic recrystallisation leads to the formation of new grains, whereas the presence of plate-like δ appears to cause the mechanical break-up and segmentation of prior grains.
Original languageEnglish
Pages (from-to)89-91
Number of pages3
JournalAdvanced Materials Research
Issue numberTHERMEC 2009 Supplement
Publication statusPublished - 5 Jan 2010
Event6th International Conference on Processing and Manufacturing of Advanced Materials - THERMEC'2009 - Berlin, Germany
Duration: 25 Aug 200929 Aug 2009


  • hot deformation
  • delta phase
  • IN718 alloy
  • Nickel-base superalloys

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