The Effect of Scandium Ternary Intergrain Precipitates in Al-Containing High-Entropy Alloys
AbstractWe investigate the effect of alloying with scandium on microstructure, high-temperature phase stability, electron transport, and mechanical properties of the Al2CoCrFeNi, Al0.5CoCrCuFeNi, and AlCoCrCu0.5FeNi high-entropy alloys. Out of the three model alloys, Al2CoCrFeNi adopts a disordered CsCl structure type. Both of the six-component alloys contain a mixture of body-centered cubic (bcc) and face centered cubic (fcc) phases. The comparison between in situ high-temperature powder diffraction data and ex situ data from heat-treated samples highlights the presence of a reversible bcc to fcc transition. The precipitation of a MgZn2-type intermetallic phase along grain boundaries following scandium addition affects all systems differently, but especially enhances the properties of Al2CoCrFeNi. It causes grain refinement; hardness and electrical conductivity increases (up to 20% and 14% respectively) and affects the CsCl-type → fcc equilibrium by moving the transformation to sensibly higher temperatures. The maximum dimensionless thermoelectric figure of merit (ZT) of 0.014 is reached for Al2CoCrFeNi alloyed with 0.3 wt.% Sc at 650 °C. View Full-Text
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Riva, S.; Mehraban, S.; Lavery, N.P.; Schwarzmüller, S.; Oeckler, O.; Brown, S.G.R.; Yusenko, K.V. The Effect of Scandium Ternary Intergrain Precipitates in Al-Containing High-Entropy Alloys. Entropy 2018, 20, 488.
Riva S, Mehraban S, Lavery NP, Schwarzmüller S, Oeckler O, Brown SGR, Yusenko KV. The Effect of Scandium Ternary Intergrain Precipitates in Al-Containing High-Entropy Alloys. Entropy. 2018; 20(7):488.Chicago/Turabian Style
Riva, Sephira; Mehraban, Shahin; Lavery, Nicholas P.; Schwarzmüller, Stefan; Oeckler, Oliver; Brown, Stephen G.R.; Yusenko, Kirill V. 2018. "The Effect of Scandium Ternary Intergrain Precipitates in Al-Containing High-Entropy Alloys." Entropy 20, no. 7: 488.
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