Segregation, ordering, and precipitation in WTaV-based concentrated refractory alloys
Tungsten-based low-activation high-entropy alloys are possible candidates for next-generation fusion reactors
due to their exceptional tolerance to irradiation, thermal loads, and stress. We develop an accurate and
efficient machine-learned interatomic potential for the W–Ta–Cr–V system and use it in hybrid Monte Carlo
molecular dynamics simulations of ordering and segregation to all common types of defects in WTaCrV. The
predictions are compared to atom probe tomography analysis of segregation and precipitation in WTaCrV
thin films. By also considering two other alloys, WTaV and MoNbTaVW, we are able to draw general
conclusions about preferred segregation in refractory alloys and the reasons behind it, guiding future alloy
design and elucidating experimental observations. We show that the experimentally observed CrV precipitates
in WTaCrV form semicoherent bcc-to-bcc interfaces with the surrounding matrix, as coherent precipitates are
not thermodynamically stable due to excessive lattice mismatch. The predictions from simulations align well
with our atom probe tomography analysis as well as previous experimental observations.