Development of reduced-activation and radiation-resistant high-entropy alloys for fusion reactor

Abstract

With the development of advanced nuclear reactors such as fusion reactors and Generation IV reactors, structural materials for nuclear applications will face increasingly extreme service environments, including higher temperatures and stronger neutron irradiation. Existing structural materials may not be capable of meeting the performance requirements, emphasizing the necessity for developing new materials with enhanced high-temperature mechanical properties and irradiation resistance. High-entropy alloys (HEAs) have garnered significant attention in the field of nuclear materials due to their exceptional overall performance, particularly in the irradiation resistance. However, the composition of commonly HEAs based on face-centered cubic (FCC), body-centered cubic (BCC), and FCC + BCC phases, as defined by metallic systems containing four, five or more components in equimolar or near-equimolar ratios, does not meet the requirement of reduced activation. Thus, there is an urgent need to develop reduced-activation high entropy alloys (RAHEAs) for using in nuclear reactors. This article presents a review of the current research on RAHEAs, focusing on composition design, phase composition, mechanical properties, and irradiation properties. Among the various RAHEAs, two specific types deserve particular attention: nanoprecipitation-reinforced RAHEAs and oxide dispersion-strengthened (ODS) RAHEAs. These novel alloys may exhibit high mechanical properties and robust irradiation resistance, while also mitigating the brittleness issue often encountered with current RAHEAs. With a vast compositional space available for adjustments, RAHEAs hold significant potential for designing superior structural materials for use in advanced nuclear reactors.