High-entropy alloys for nuclear applications

High-entropy alloys (HEAs) because of their attractive properties, provide a unique opportunity to develop materials suitable for structural applications in the harsh environment (high-temperature and intense irradiation) prevailing in Gen IV nuclear power reactors. HEAs based on refractory elements (RHEAs) can display excellent stability at high temperatures and superior irradiation resistance due to the BCC-based structures obtained in most alloys. In this regard, the design and development of RHEAs based on the ZrNbVTiAl system have been actively pursued at BARC. Detailed characterization of microstructure and mechanical properties of these alloys having equiatomic and non-equiatomic compositions have been carried out. The study revealed the possibility of attaining significantly higher strengths up to 1.25 GPa and excellent fabricability as a result of dynamic recrystallization at high temperatures. In addition, the dissolution of AlZr-type intermetallics was observed after proton irradiation which helped in bringing the system towards a single-phase BCC structure.