Stable nanocrystalline NbMoTaW high entropy alloy thin films with excellent mechanical and electrical properties

In this work, we systematically investigated the hardness, electrical resistance and thermal stability of nanocrystalline NbMoTaW high entropy alloy films with thickness varying from about 100 to 2000 nm. The nanocrystalline high entropy alloy film exhibited the peak hardness (∼16.0 GPa), strong size-independent electrical resistance (∼170 μΩ·cm) as well as stabilized single phase body-centered cubic (BCC) structure even after exposed to vacuum annealing at 800 °C for 2 h. In the meantime, we provide reasonable insights into understanding behaviors above. With superior mechanical and electrical properties as well as good thermal stability, this kind of refractory nanocrystalline HEAFs will find extensive potential applications.