Phase Transformations during Low Temperature Nitrided Inconel 718 Superalloy

Jin, Yan; Wang, Jun; Gu, Tingyue; Xiong, Ji; Fan, Hongsong

doi:10.2355/isijinternational.isijint-2015-697

Cited by 13 publications

(20 citation statements)

References 31 publications

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“…Nitriranje u tečnoj sredini smatra se štetnim po životnu sredinu od strane mnogih istraživača. Jing i grupa autora [49] smatraju istinitim da glavne komponente konvencionalnih sonih kupatila za nitriranje sadrže ureu, karbonat, hlorid i neke netoksične komponente u tragovima. Međutim, oni naglašavaju da ako se NH 3 gas i otpadna šljaka pravilno kontrolišu, nitriranje u tečnoj sredini je tehnologija koja ne šteti životnoj sredini.…”

Section: Problemi Koji Izazivaju Potrebu Za Plazma Nitriranjeunclassified

Directions of development and application of plasma nitriding in industry

Stojanović¹,

Stanisavljev²,

Erić³

2022

Zaštita materijala

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This paper presents a discussion of the results of previous research of the effects of surface modification of structural materials and tool steels using plasma nitriding (PN) in order to improve their mechanical, tribological and corrosion behavior. The paper discusses the current status and future directions in the application of PN on various wearing components that are exposed to high loads, stresses and frequent temperature changes. The paper provides an overview of the relevant literature whose results show the most favorable or optimal parameters of the PN process aimed at achieving the best performance in terms of wear and corrosion resistance and hardness increase for the various materials considered. Systematization of literature data about research of the impact of low-temperature PN on stainless steels has placed emphasis on those process mechanisms that achieve benefits for surface layers without creating negative side effects in the form of loss of corrosion resistance. The strengthening of hot forging dies is considered through the reasons and problems that cause the need for the application of PN, and then paper focuses on the role of PN in achieving the tribological properties required to extend the service life of the die. Publications in which the nitriding of titanium alloys is investigated through the reduction of wear, increase of bearing capacity and microhardness depending on the input parameters of the process, ie the optimal parameters applied in order to obtain the best performance characteristics are cited. The application of PN to aluminum and its alloys is discussed, as well as the conditions of testing and the achieved improvements.

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Section: Problemi Koji Izazivaju Potrebu Za Plazma Nitriranjeunclassified

Directions of development and application of plasma nitriding in industry

Stojanović¹,

Stanisavljev²,

Erić³

2022

Zaštita materijala

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“…Regardless of the type of nitriding, when it is carried out at temperatures ≤ 450 • C, the formation of a γ N phase has been confirmed [1,3,6,7,[14][15][16][17]. However, nitriding at a higher temperature (>450 • C) formed deleterious phases, identified as CrN, without the γ N phase [4,6,7,[14][15][16]18]. As for stainless steel nitriding, the growth in the layer thickness with increasing temperature or time was widely reported [7,14,18,19], following diffusion-controlled parabolic growth [6,19].…”

Section: Introductionmentioning

confidence: 98%

“…Surface modification via the nitriding of IN 718 has been developed through various techniques. Regardless of the type of nitriding, when it is carried out at temperatures ≤ 450 • C, the formation of a γ N phase has been confirmed [1,3,6,7,[14][15][16][17]. However, nitriding at a higher temperature (>450 • C) formed deleterious phases, identified as CrN, without the γ N phase [4,6,7,[14][15][16]18].…”

Section: Introductionmentioning

confidence: 99%

“…It is commonly used in the aeronautic, aero-spatial, petrol, and gas industries [2][3][4]. These Ni-based alloys are widely employed in adverse conditions involving high pressure, temperatures between −250 and 750 • C, and aggressive environments, showing good corrosion resistance [1,2,5,6]. However, it also exhibits poor wearing performance, limiting its use in several applications [7].…”

Section: Introductionmentioning

confidence: 99%

“…It aims to modify metallic alloy surfaces by introducing nitrogen to improve their tribological performance. When treated at low temperatures, a hard supersaturated interstitial solid solution layer (known as nitrogen-expanded austenite γ N or S phase) might form on the surface of stainless steels [8][9][10][11][12][13] and Ni-Cr alloys [1,3,6,7,[14][15][16]. When compared to the number of studies on stainless steel nitriding, as reviewed, for example, in [8], the research on Inconel alloy nitriding is sparse.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of the Pitting, Crevice Corrosion, and Mechanical Properties of Low-Temperature Plasma-Nitrided Inconel Alloy 718

Rosa

Calabokis

Ballesteros-Ballesteros

et al. 2023

Metals

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A comparative study on the mechanical properties, scratch resistance, and localized corrosion (pitting and crevice) of plasma-nitrided Inconel alloy 718 (UNS NO7718: IN 718) was carried out. Thermochemical treatment was performed at low temperatures (400 and 450 °C) for 4 h. The treatment formed layers with thicknesses of 7.17 ± 0.89 µm (400 °C) and 7.96 ± 0.48 µm (450 °C). The XRD and nanohardness analyses indicated the formation of a hard layer composed of the expanded austenite phase (γN), CrN at 400 °C, and CrN + γ at 450 °C, with a maximum indentation hardness of 12 and 12.5 GPa, respectively, when compared to the 5 GPa substrate hardness. The scratching tests (2–8 N) showed that with increasing load, the nitrided surfaces had a transition from 100% microcutting to a combination of microplowing/cutting, with the presence of cracks. The critical load of the nitrided surfaces was 3 N for 400 °C and 4 N for 450 °C. The untreated condition maintained a crack-free combined mechanism regardless of the load. For the same load, the nitrided surfaces held lower coefficient of friction values and higher scratch resistance values, which were more pronounced at 450 °C. The linear polarization tests (3.56 wt.% NaCl) showed pitting corrosion in all samples, with the 450 °C condition being less resistant. Nitriding at 400 °C increased the crevice corrosion resistance of Inconel, while at 450 °C, it severely damaged it. Nitriding at 400 °C brought concomitant gains in hardness and scratch and crevice corrosion resistance when compared to the as-received IN 718.

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