Temperature dependent small-scale deformation of a refractory high entropy alloy

Temperature-dependent deformation behavior of [110] oriented micropillars of HfTaTiVZr refractory high entropy alloy (RHEA) was studied. Engineering stress-strain curves, strain rate sensitivity measurements, and insitu observations revealed distinct deformation mechanisms at different temperatures: homogeneous at room temperature (RT), intermittent plasticity at 200 degrees C, chaotic stress drops at 400 degrees C, brittle failure at 600 degrees C, and creep-like behavior at 800 degrees C. Deformation morphology of the micropillars showed activation of few slip systems at RT and 200 degrees C, multiple slip systems at 400 degrees C, catastrophic failure at 600 degrees C, and minimal slip activity at 800 degrees C. These findings offer unique insights into the deformation of RHEAs.