Tao, X., Matthews, A. and Leyland, A. orcid.org/0000-0002-5569-7293 (2020) On the nitrogen-induced lattice expansion of a non-stainless austenitic steel, Invar 36®, under triode plasma nitriding. Metallurgical and Materials Transactions A, 51 (1). pp. 436-447. ISSN 1073-5623
Abstract
Chromium, as a strong nitride-forming element, is widely regarded to be an “essential” ingredient for the formation of a nitrogen-expanded lattice in thermochemical nitrogen diffusion treatments of austenitic (stainless) steels. In this article, a proprietary “chrome-free” austenitic iron-nickel alloy, Invar® 36 (Fe-36Ni, in wt pct), is characterized after triode plasma nitriding (TPN) treatments at 400 °C to 450 °C and compared with a “stainless” austenitic counterpart RA 330® (Fe-19Cr-35Ni, in wt pct) treated under equivalent nitriding conditions. Cr does indeed appear to play a pivotal role in colossal nitrogen supersaturation (and hence anisotropic lattice expansion and superior surface hardening) of austenitic steel under low-temperature (≤ 450 °C) nitrogen diffusion. Nevertheless, this work reveals that nitrogen-induced lattice expansion occurs below the nitride-containing surface layer in Invar 36 alloy after TPN treatment, implying that Cr is not a necessity for the nitrogen-interstitial induced lattice expansion phenomenon to occur, also suggesting another type of γN.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 The Minerals, Metals & Materials Society and ASM International. This is an author-produced version of a paper subsequently published in Metallurgical and Materials Transactions A. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 11 Dec 2019 13:55 |
Last Modified: | 15 Oct 2021 07:59 |
Status: | Published |
Publisher: | Springer Nature |
Refereed: | Yes |
Identification Number: | 10.1007/s11661-019-05526-0 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:154515 |