Microstructure and mechanical properties of novel tungsten heavy alloys prepared using FeNiCoCrCu HEA as binder

Panigrahi, A and Acharya, TS and Sengupta, P and Kumar, D and Sarangi, L and Kumar, N and Debasish, D and Suwas, S and Basu, S and Debata, M (2022) Microstructure and mechanical properties of novel tungsten heavy alloys prepared using FeNiCoCrCu HEA as binder. In: Materials Science and Engineering A, 832 .

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Abstract

In the present work, novel tungsten heavy alloys (WHAs) have been developed using FeNiCoCrCu high entropy alloy (HEA) as binder through conventional sintering process. The composition of the alloy is 90 wt W-10 wt HEA. FeNiCoCrCu HEA was prepared by mechanical milling of elemental Fe, Ni, Co, Cr, and Cu powders in an equiatomic ratio for 60 h. XRD analyses revealed that HEA contains predominant FCC phase along with BCC minor phase. In order to evaluate the effectiveness of FeNiCoCrCu HEA as a binder of WHA, in this study, W and HEA were mixed in the ratio of 9:1, pressed and sintered at temperatures of 1470 and 1500 °C for dwell time of 1 h 30 min under hydrogen atmosphere. These sintered samples are mentioned as WHEAs (W-High Entropy Alloys). The evolution of phases, microstructures, and mechanical properties was investigated as a function of sintering temperature vis-á-vis those prepared by mixing of W and Fe, Ni, Co, Cr, Cu in the same proportion as in HEA (W-EleMental: WEM). The effect of hydrogen treatment (HyT) prior to the sintering of WHEAs on above mentioned characteristics was studied. Structural investigation of WEMs and WHEAs showed high intense W-peaks. Micrographs of these sintered samples showed typical liquid phase sintered microstructures having three distinct phases: bright W-phase, gray matrix phase, and black Cr-oxide phase. With the increase of sintering temperature and introduction of HyT step, the volume fraction of solid W-grain has been increased and W-content in the matrix of WHEAs is reduced. Upon sintering, WHEAs yield better densification, higher compressive strength, and higher bulk hardness. This increase of strength from WEMs to WHEAs was attributed to better densification of WHEAs compared to the former. The maximum values of compressive strength (1912 ± 14 MPa) and bulk hardness (479 ± 16 VHN) were achieved in the case of hydrogen treated W-HEA powder sintered at 1500 °C. © 2021 Elsevier B.V.

Item Type:	Journal Article
Publication:	Materials Science and Engineering A
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to Elsevier Ltd.
Keywords:	Atmospheric temperature; Chromium alloys; Cobalt alloys; Compressive strength; Copper; Entropy; Hardness; High-entropy alloys; Hydrogen; Iron alloys; Mechanical alloying; Milling (machining); Sintering; Tungsten alloys, Conventional sintering; Densifications; High entropy alloys; Hydrogen treatments; Microstructures and mechanical properties; Sintered samples; Sintering temperatures; Tungsten heavy alloys; Tungsten-high entropy alloy, Microstructure
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	06 Jan 2022 11:38
Last Modified:	06 Jan 2022 11:38
URI:	http://eprints.iisc.ac.in/id/eprint/70802

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