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Theoretical critical metastability temperature to interpret phase formation in a lamellar-like- structured high entropy alloy

Nordin, Norhuda Hidayah and Leong, Zhaoyuan and Goodall, Russel and Todd, Iain (2022) Theoretical critical metastability temperature to interpret phase formation in a lamellar-like- structured high entropy alloy. Journal of Materials Research and Technology, 18. pp. 2519-2530. ISSN 2238-7854 E-ISSN 2214-0697

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Control over a lamellar-like-structured high entropy alloy (HEA) system is found to be possible by replacement of aluminium with boron into the FeCoNi(Bx Al1-x)0.1Si0.1 composition in the range of x = 0 to 1.0. The BCC/B2 microstructure of FeCoNi(Al0.1Si0.1) HEA is changed into a multiple phase system comprising of BCC/B2, FCC and Fe2B-type intermetallic phases. The microstructures of as-cast alloys were seen to be a lamellar-like structure comprised of nanostructured lamellae with alternating FCC and Fe2B phases. The concept of critical metastability temperature from nucleation theory is employed phenomenologically, and found to correlate with the presence of Fe2B in this alloy at different boron additions. With the substitution of boron, the stability of the disordered BCC solid solution is reduced, promoting the formation of secondary phases. We show a link between the interfacial energy of the phases present, the interlamellar spacing, and alloy metastability as a function of boron addition, the key relationship being that Fe2B phase formation correlates with a drastic reduction in the interfacial energy. These correlations bear further investigation and may be useful in the design of lamellar-like-structured multi-component systems.

Item Type: Article (Journal)
Uncontrolled Keywords: High entropy alloys Microstructure Interfacial energy Phase transformation
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA401 Materials of engineering and construction
T Technology > TN Mining engineering. Metallurgy
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button): Kulliyyah of Engineering > Department of Manufacturing and Materials Engineering
Date Deposited: 11 Apr 2022 08:08
Last Modified: 11 Apr 2022 08:08
URI: http://irep.iium.edu.my/id/eprint/97560

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