Microstructural and Mechanical Characterization of Laser Powder Bed Fusion of IN718 Overhangs

Access full-text files

Date

2021

Authors

Hanumantha, M.
Farhang, B.
Ravichander, B.B.
Ganesh-Ram, A.
Ramachandra, S.
Finley, B.E.
Swails, N.
Amerinatanzi, A.

Journal Title

Journal ISSN

Volume Title

Publisher

University of Texas at Austin

Abstract

Inconel 178 (IN718), a nickel-chromium-based superalloy known for its superior properties is used in aerospace, oil, and gas industries. Due to its high hardness, IN718 is difficult to be machined. Therefore, fabrication of IN718 components with complex geometries is a big challenge when conventional manufacturing techniques are used. Laser powder bed fusion (LPBF) technique can be used to fabricate IN718 parts with high precision. During fabrication of overhang structures, supports are typically employed, which significantly increases the use of resources such as material consumption and postprocessing. The focus of this study is to determine the angle at which an overhang structure can be fabricated without employing supports. To this aim, the angled-overhang samples with varied angles (30°-90°) were manufactured with no support. The effect of overhang state on the microstructural and mechanical properties of the LPBF-processed IN718 samples was analyzed. According to the microstructural analysis, the deepest melt pools in the overhang sample seemed to be at a hanging angle of 45°. Moreover, the overhang sample fabricated at 45° had the greatest Vickers hardness value of 382.90 HV. This study urges a reconsideration of the common approach of selecting supports for overhang samples in the LPBF process when a higher quality of the as-fabricated parts is desired.

Description

LCSH Subject Headings

Citation