Microstructure of IN738LC fabricated using laser powder bed fusion additive manufacturing

Nandana Menon, Tanjheel Hassan Mahdi, Amrita Basak

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Nickel-base superalloys are extensively used in the production of gas turbine hot-section components as they offer exceptional creep strength and superior fatigue resistance at high temperatures. Such improved properties are due to the presence of precipitate-strengthening phases such as Ni3Ti or Ni3Al (γ' phases) in the normally face-centered cubic (FCC) structure of the solidified nickel. Although this second phase is the main reason for the improvements in properties, the presence of such phases also results in increased processing difficulties as these alloys are prone to crack formation. In this work, specimens of IN738LC are fabricated on a Coherent Creator laser powder bed fusion (L-PBF) additive manufacturing (AM) equipment. Optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and X-Ray diffraction (XRD) are carried out to characterize the deposit region. Metallurgical continuity is achieved in the entire deposit region and the specimens do not show any warpage. However, the specimens show voids (e.g., pores and cracks) in the deposit region. The results show that the percentage void area decreases along the build height direction. The deposited IN738LC shows polycrystalline grains in the entire deposit region as confirmed by XRD and EBSD. The grain size also shows variations along the build direction. In summary, the results open opportunities for academic researchers and small-scale businesses in fabricating high-γ' nickel-base superalloys on a desktop laser powder bed fusion AM equipment.

Original languageEnglish (US)
Title of host publicationIndustrial and Cogeneration; Manufacturing Materials and Metallurgy
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791885000
DOIs
StatePublished - 2021
EventASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition, GT 2021 - Virtual, Online
Duration: Jun 7 2021Jun 11 2021

Publication series

NameProceedings of the ASME Turbo Expo
Volume7

Conference

ConferenceASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition, GT 2021
CityVirtual, Online
Period6/7/216/11/21

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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