Morphology and Grain Texture in As-Deposited and Heat Treated Inconel 718 Structures Produced using Laser-Based Powder Bed Fusion

David B. Saint John, Sanjay B. Joshi, Timothy W. Simpson, Meng Qu, John David Rowatt, Yucun Lou

Research output: Contribution to conferencePaper

1 Scopus citations

Abstract

With increasing interest in the use of powder bed fusion (PBF) processes for additive manufacturing, understanding the relationship between as-deposited and heat treated states and the intrinsic anisotropy of fabricated parts has become critical for its successful application. This phenomenon has been studied and reported extensively for Inconel 718 parts fabricated using PBF for aerospace applications, but few reports exist on the morphology and grain texture of Inconel 718 parts fabricated for oil and gas applications, which have different demands. This work demonstrates that the anisotropy in Inconel 718 parts produced using laser-based PBF is not entirely removed by subsequent heat treatments, and it may be an artifact of the as-deposited grain structure, whose elongated grains may stretch through several melt pools. The as-built material is observed to exhibit some texturing, with (001) being the preferential growth direction. Despite some residual anisotropy, heat treatments are sufficient to provide material qualities that meet specification, even without the use of a HIP (hot isostatic pressing) step. It is hypothesized that similarly elongated grain structures may explain the anisotropy observed in other materials systems employed in PBF additive manufacturing processes.

Original languageEnglish (US)
Pages530-541
Number of pages12
StatePublished - 2016
Event27th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2016 - Austin, United States
Duration: Aug 8 2016Aug 10 2016

Conference

Conference27th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2016
CountryUnited States
CityAustin
Period8/8/168/10/16

All Science Journal Classification (ASJC) codes

  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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    Saint John, D. B., Joshi, S. B., Simpson, T. W., Qu, M., Rowatt, J. D., & Lou, Y. (2016). Morphology and Grain Texture in As-Deposited and Heat Treated Inconel 718 Structures Produced using Laser-Based Powder Bed Fusion. 530-541. Paper presented at 27th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2016, Austin, United States.