Investigation of process factors affecting mechanical properties of INCONEL 718 superalloy in wire + arc additive manufacture process

By Xiangfang Xu, Jialuo Ding, S. Ganguly, Stewart W. Williams. Journal of Materials Processing Technology, 2019

157 citations recorded by the source corpus.

Abstract This paper systematically evaluated the effect of oxide, wire source and heat treatment on the mechanical properties of wire + arc additively manufactured (WAAM) INCONEL 718. Comparison of the as deposited grain structure was made with laser-powder based AM and wrought INCONEL 718. Results showed that oxides formed during deposition had no effect on the mechanical properties since a 0.5μm thick passivation layer consisting of Cr2O3 and Al2O3 formed upon deposition and prevented further oxides from forming inside the bulk. Wires from different suppliers resulted in around 50 MPa difference in UTS possibly due to the slight compositional variation and uncertainties in TiN inclusion. Standard heat treatment improved the strength from 824 MPa to 1110 MPa in the horizontal direction, but the average strength was 105 MPa lower than the wrought alloy. The as deposited WAAM INCONEL718 featured large columnar grains and numerous Laves phase, as compared to the fine grains of laser powder bed fusion and wrought INCONEL 718. This starting microstructure led to less favourable and less numerous precipitates forming during heat treatment, which is the main reason for the strength mismatch. A different heat treatment would not help due to the starting microstructure.

Subfields: Automotive Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/6155eb4fc48e989e834ece8c10812796e1e5b277

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Citations in the corpus

Wire and arc additive manufacturing of a Ni-rich NiTi shape memory alloy: Microstructure and mechanical properties (2020, methodology): “SMAs research work conducted to date has focused on powder-bed systems using a 47 laser [10, 11] or an electron beam [12-14] as the heat source.”
The Current State of Research of Wire Arc Additive Manufacturing (WAAM): A Review (2021, methodology): “Different common nickel base alloys are being used for additive manufacturing like Inconel 625 [327,337,340], Hastelloy C276 [335] or Inconel 718 [328,329,333].”
Current Status and Perspectives on Wire and Arc Additive Manufacturing (WAAM) (2019, background): “[64], evaluated the effect of oxides and different types of wires on the final properties of Inconel 718, since this alloy is known for its oxidation-assisted crack growth mechanism at high temperatures [65].”
An overview of wire arc additive manufacturing (WAAM) in shipbuilding industry (2020, background): “Xu et al. (2019) suggested proper heat treatment and post-processing in order to reduce the cracking that occurs in Inconel 625 and Inconel 718.”
Wire + Arc Additively Manufactured Inconel 718: Effect of post-deposition heat treatments on microstructure and tensile properties (2019, methodology): “Although separate tensile properties for WAAM IN718 loaded in different directions have been reported [10], the extent of their anisotropy has not been quantified, and their relationship with the anisotropic grain structure remains unclear.”