Unusual plate-type iron-carbonitrides development in nitrocarburized Fe-4 at. V alloy

Kashyap, A and Vishwanadh, B and Chauhan, A and Meka, SR (2024) Unusual plate-type iron-carbonitrides development in nitrocarburized Fe-4 at. V alloy. In: Acta Materialia, 263 .

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Abstract

The influence of substitutionally dissolved V in ferritic Fe-4 at. V alloy, on the structure and morphology of iron-carbonitrides ε-Fe3(N, C)1+x and γ'-Fe4(N, C)1-y was investigated upon salt bath nitrocarburizing. An unusual plate-type morphology of γʹ and ε carbonitrides development was evidenced during nitrocarburizing of Fe-V alloy as against to the usual layer-type growth of γʹ and ε nitrides reported for nitrided Fe-V alloys. The ε phase developed first along ferrite matrix grain boundaries, followed by its formation as plates on the plates of γʹ within the grains of ferrite matrix and finally as a layer at the surface. In contrast to ε, γʹ has developed only as plates within the ferrite matrix grains either with Kurdjumov-Sachs or Pitsch orientation relationship. Initially the inwardly diffusing N gets consumed for the development of VN precipitates in the ferrite matrix while C gets enriched at the ferrite-matrix grain boundaries leading to the development of ε carbonitride. Once all the V precipitates as VN, the development of γʹ occurs as plates within the grains and upon further increase in the N content lead to the development of ε within grains. This demonstrates that as a consequence of drastically different solubility and diffusivity of C and N in ferrite, ε and γʹ phases can lead complex microstructural evolution upon nitrocarburizing of Iron-based alloys. © 2023 Acta Materialia Inc.

Item Type:	Journal Article
Publication:	Acta Materialia
Publisher:	Acta Materialia Inc
Additional Information:	The copyright for this article belongs to elsevier publishers.
Keywords:	Binary alloys; Ferrite; Grain boundaries; Iron alloys; Iron compounds; Lead compounds; Morphology; Plates (structural components); Vanadium compounds, Ferrite matrix; Ferritic; Grain-boundaries; Iron carbonitride; Matrix grains; Nitrides morphology; Nitrocarburized; Plate-Type; Salt bath; Structure and morphology, Carbon nitride
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	28 Feb 2024 11:01
Last Modified:	28 Feb 2024 11:01
URI:	https://eprints.iisc.ac.in/id/eprint/83708

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