Superplastic-like flow behavior in Al0.2CoCrFeNiMo0.5 high entropy alloy

Abstract

High temperature tensile experiments were performed on Al0.2CoCrFeNiMo0.5 high entropy alloy in the temperature range of room temperature (RT) to 900 °C. It exhibited good resistance to softening up to 700 °C, and thereafter a rapid decrease in the strength was observed. Superplastic-like tensile elongation of ∼ 275 % was observed at a strain rate of 1x10-3 s−1 and at a temperature of 900° C. Tensile experiments at different strain rates along with strain rate jump experiments at 900 °C showed a strain rate sensitivity of ∼ 0.32. Kernal Average Misorientation (KAM) maps at the gauge and grip portions along with texture pole figure analysis suggesting that dislocation glide might be the active deformation mode responsible for large tensile elongation. Cavitation along the secondary phase-matrix interphase was the dominant failure mode.