Effect of post processing on the creep performance of laser powder bed fused Inconel 718

Xu, Z.; Murray, J.W.; Hyde, C.J.; Clare, A.T.

Abstract

In this study, the creep performance of laser powder bed fusion manufactured Inconel 718 specimens is studied in detail and compared with conventional hot-rolled specimens alongside as-built then heat-treated and as-built then hot-isostatic pressed specimens. Hot-rolled specimens showed the best creep resistance, while the hot-isostatic pressed specimens yielded the worst performance, inferior to the as-built condition. Creep testing of all samples showed increased secondary creep rate was consistently correlated with a reduced life. Fractography revealed intergranular fracture was the primary failure mode for all as-built samples. Preferential intergranular precipitation in the case of the hot-isostatic pressed specimens during hot-isostatic pressing extensive intergranular cracking as the primary failure mechanism. Heat-treated specimens possessed only sparse intergranular precipitates, thereby explaining an improved creep lifetime. The hot-rolled specimens, having smallest grain size, showed the least extensive cracking, particularly in locations of finest grains, explaining avoidance of intergranular fracture as a key creep mechanism, thereby explaining the ductile creep fracture surfaces in the case of the hot-rolled samples.

Citation

Xu, Z., Murray, J., Hyde, C., & Clare, A. (2018). Effect of post processing on the creep performance of laser powder bed fused Inconel 718. Additive Manufacturing, 24, 486-497. https://doi.org/10.1016/j.addma.2018.10.027

• Journal Article Type: Article
• Acceptance Date: Oct 18, 2018
• Online Publication Date: Oct 22, 2018
• Publication Date: Dec 1, 2018
• Deposit Date: Oct 29, 2018
• Publicly Available Date: Oct 23, 2019
• Journal: Additive Manufacturing
• Print ISSN: 2214-7810
• Electronic ISSN: 2214-8604
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 24
• Pages: 486-497
• DOI: https://doi.org/10.1016/j.addma.2018.10.027
• Keywords: Creep; Laser powder bed fusion; Inconel 718; Heat treatment; Hot-isostatic pressing
• Public URL: https://nottingham-repository.worktribe.com/output/1206221
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S2214860418305578?dgcid=author
• Additional Information: This article is maintained by: Elsevier; Article Title: Effect of post processing on the creep performance of laser powder bed fused Inconel 718; Journal Title: Additive Manufacturing; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.addma.2018.10.027; Content Type: article; Copyright: © 2018 Elsevier B.V. All rights reserved.; ; A.T. Clare also based at Department of Mechanical, Materials and Manufacturing Engineering, Faculty of Science and Engineering, University of Nottingham China, Ningbo