Campus Units

Materials Science and Engineering

Document Type

Article

Publication Version

Published Version

Publication Date

10-15-2019

Journal or Book Title

Materials & Design

Volume

180

First Page

107915

DOI

10.1016/j.matdes.2019.107915

Abstract

When Inconel 718 alloy is fabricated by selective laser melting and treated by traditional homogenization plus double aging heat treatment (HA), its strength improves greatly, but ductility decreases. A novel heat treatment (NHT) including higher temperature homogenization at 1150 °C for 2 h and one-time lower temperature aging treatment at 700 °C for 12 h is developed, which can overcome the strength-plasticity trade-off of Inconel 718 alloy. The results show that recrystallized grains with annealing twins and ultrafine strengthening phases form in the specimen subjected to the NHT. These microstructures differ from those in as-built and conventional heat-treated samples. Especially the morphology of strengthening phase γ″-Ni3Nb precipitated in the NHT specimen has changed a lot, it seems to be spherical rather than disc-like shape occurred in the traditional heat-treated samples. Consequently, the NHT process increases plasticity by 41%, while maintaining ultimate strength at the same level achieved by the traditional heat treatment. The enhanced ductility is attributed to the annealing twins and recrystallized grains without local strains, while the strength is provided by the smaller precipitates formed in the NHT one-time aging treatment.

Comments

This article is published as Li, X., J. J. Shi, G. H. Cao, A. M. Russell, Z. J. Zhou, C. P. Li, and G. F. Chen. "Improved plasticity of Inconel 718 superalloy fabricated by selective laser melting through a novel heat treatment process." Materials & Design (2019): 107915. DOI: 10.1016/j.matdes.2019.107915. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

The Authors

Language

en

File Format

application/pdf

Included in

Metallurgy Commons

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