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High-pressure high-temperature tailoring of High Entropy Alloys for extreme environments / Kirill Yusenko, Sephira Riva, Wilson A. Crichton, Kristina Spektor, Elena Bykova, Anna Pakhomova, Adam Tudball, Ilya Kupenko, Arno Rohrbach, Stephan Klemme, Francesco Mazzali, Serena Margadonna, Nicholas Lavery, Steve Brown

Journal of Alloys and Compounds, Volume: 738, Pages: 491 - 500

Swansea University Authors: Kirill Yusenko, Serena Margadonna, Nicholas Lavery, Steve Brown

Abstract

The exceptional performance of some High Entropy Alloys (HEAs) under extreme conditions holds out the possibility of new and exciting materials for engineers to exploit in future applications. In this work, instead of focusing solely on the effects of high temperature on HEAs, the effects of combine...

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Published in: Journal of Alloys and Compounds
ISSN: 0925-8388
Published: 2018
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa37789
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Abstract: The exceptional performance of some High Entropy Alloys (HEAs) under extreme conditions holds out the possibility of new and exciting materials for engineers to exploit in future applications. In this work, instead of focusing solely on the effects of high temperature on HEAs, the effects of combined high temperature and high pressure were observed. Phase transformations occurring in a pristine HEA, the as-cast bcc–Al2CoCrFeNi, are heavily influenced by temperature, pressure, and by scandium additions. As-cast bcc–Al2CoCrFeNi and fcc–Al0.3CoCrFeNi HEAs are structurally stable below 60 GPa and do not undergo phase transitions. Addition of scandium to bcc–Al2CoCrFeNi results in the precipitation of hexagonal AlScM intermetallic (W-phase), which dissolves in the matrix after high-pressure high-temperature treatment. Addition of scandium and high-pressure sintering improve hardness and thermal stability of well-investigated fcc- and bcc- HEAs. The dissolution of the intermetallic in the main phase at high pressure suggests a new strategy in the design and optimization of HEAs.
Keywords: High-entropy alloys; Scandium; High-pressure high-temperature sintering; Spark plasma sintering; In situ X-ray diffraction
College: College of Engineering
Start Page: 491
End Page: 500