Effects of nanotwins on the mechanical properties of AlxCoCrFeNi high entropy alloy thin films

Abstract In this work, we investigate the plastic deformation characteristics (hardness, strain rate sensitivity and activation volume) of nanotwinned Al x CoCrFeNi (x = 0, 0.1, 0.3) high entropy alloy thin films (HEAFs). The extremely thin nanotwins with thickness of ~ 2 nm soften these HEAFs, but enhance their strain rate sensitivity. We combine the detwinning softening process with conventional strengthening mechanisms to elucidate the mechanical properties of Al x CoCrFeNi HEAFs. These findings provide deep insights into design strategies to explore the promising high entropy alloys, especially the nanotwinned HEAFs at micro- and nano-scale.