Search

Excellent castability, significantly refined microstructure, and good mechanical properties make eutectic high‐entropy alloys (EHEAs) a natural fit for rapid solidification processes, e.g., additive manufacturing. Previous investigations have focused on developing EHEAs through trial and error and mixing known binary eutectic materials. However, eutectic compositions obtained from near‐equilibrium conditions do not guarantee a fully eutectic microstructure under rapid solidifications. In this work, a thermodynamically guided high‐throughput framework is proposed to design EHEAs for rapid solidification. Empirical formulas derived from past experimental observations and thermodynamic computations are applied and considered phase growth kinetics under rapid solidification (skewed phase diagram). The designed alloy candidate, Co25.6Fe17.9Ni22.4Cr19.1Ta8.9Al6.1 (wt.%), contains nanostructured eutectic lamellar and shows a high Vickers hardness of 675 Hv. In addition to this specific composition, the alloy design toolbox enables the development of new EHEAs for rapid solidification without the limitation of previous knowledge. [ABSTRACT FROM AUTHOR]

Nuclear fusion energy holds great promise for being the ultimate solution to the ever-expanding energy needs of modern civilization. Based on the ideal operating temperature ranges of the plasma-facing armour materials and molten salt coolant in tokamak fusion reactors, there is a significant unutilized temperature gradient of ∼973–1273 K that can be potentially harvested by thermoelectric (TE) devices, without affecting the efficiency of the existing molten salt's heat cycle. In this review, we assess the potential suitability of various high temperature TE materials, such as Si1−xGex, n-type La3−xTe4, p-type Yb14(Mg,Mn)Sb11 zintl compounds, p-type B4C and other borides, for applications on plasma-facing surfaces of nuclear fusion reactors. The practical considerations of plasma-facing TE devices in fusion reactors were also discussed in detail, where potential overlaps between material modifications for enhancing TE properties and neutron irradiation resistance in materials were identified, together with compromises in TE device design parameters. Lastly, transverse TE materials, especially high temperature goniopolar Re4Si7 were also discussed in relation to their potential for Ettingshausen refrigeration for liquid He-free cooling of magnetic field coils. With the continued development of improved fusion reactor designs and structural materials, more opportunities for TE material applications are bound to open up, catalysing the advancement of TE material development for applications under extreme conditions. [ABSTRACT FROM AUTHOR]