High Radiation Resistance in the Binary W-Ta System Through Small V Additions: A New Paradigm for Nuclear Fusion Materials
Refractory High-Entropy Alloys (RHEAs) are promising candidates for
structural materials in nuclear fusion reactors, where W-based alloys are
currently leading. Fusion materials must withstand extreme conditions,
including i) severe radiation damage from energetic neutrons, ii)
embrittlement due to H and He ion implantation, and iii) exposure to high
temperatures and thermal gradients. Recent RHEAs, such as WTaCrV and
WTaCrVHf, have shown superior radiation tolerance and microstructural
stability compared to pure W, but their multi-element compositions
complicate bulk fabrication and limit practical use. In this study, it is
demonstrated that reducing alloying elements in RHEAs is feasible without
compromising radiation tolerance. Herein, two Highly Concentrated
Refractory Alloys (HCRAs) − W53Ta44V3 and W53Ta42V5 (at.%) − were
synthesized and investigated. We found that small V additions significantly
influence the radiation response of the binary W–Ta system. Experimental
results, supported by ab-initio Monte Carlo simulations and
machine-learning-driven molecular dynamics, reveal that minor variations in
V content enhance Ta–V chemical short-range order (CSRO), improving
radiation resistance in the W53Ta42V5 HCRA. By focusing on reducing
chemical complexity and the number of alloying elements, the conventional
high-entropy alloy paradigm is challenged, suggesting a new approach to
designing simplified multi-component alloys with refractory properties for
thermonuclear fusion applications.