Study of the effect of dual-phase transformation on the processing map of Al0.9FeCoNiCr high-entropy alloys under peak stress conditions

Abstract

Single-pass thermal compression simulation experiments were performed on a dual-phase Al0.9FeCoNiCr high-entropy alloy at strain rates of 1–0.001 s−1, temperatures of 850–1050°C (true strain of 0.916). According to a model of the dynamic DMM processing map proposed by Prasad et al, the hot-deformation behaviour of the alloy was analysed. The flow-instability regions were obtained as follows: temperature 850–1040°C with a strain rate 1–0.1 s−1 and 850–900°C with a strain rate of 1–0.001 s−1. The microstructure was obtained by EBSD characterisation. It was found that under certain strain-rate conditions, the FCC phase in the dual-phase Al0.9FeCoNiCr high-entropy alloy did not change significantly at low temperatures but increased significantly when the temperature was over 1000°C. The hot-working properties of the alloy are affected when the FCC phase exceeds 80%.

Keywords

• Al0.9FeCoNiCr HE alloy
• processing map model
• hot-deformation behaviour
• microstructural evolution