Study on the Deformation Mechanism of a Nonequiatomic AlCrMnFeNi High-Entropy Alloy at Cold and Warm Temperatures

Abstract

High-entropy alloys (HEAs) have led to breakthroughs in materials science due to their superior properties and the challenge of achieving the high strength and high ductility trade-off. Microstructural evolution during cold and warm compression tests of the single-phase Al8Cr12Mn25Fe35Ni20 high entropy alloy (Fe-HEA) is investigated in the present work. The current study assesses the effect of temperature on the mechanical properties and deformation mechanism of the face-centered cubic structure Fe-HEA. The arc-melted ingot is homogenized at 1473 K and then directly hot-rolled to break the cast structure of the alloy prior to testing procedures. Fe-HEA is tested through uniaxial compressive testing at three different selected temperatures: 293, 473, and 673 K utilizing a Gleeble thermo-mechanical simulator at a strain rate of 0.001 s-1. The compressive behavior at 673 K showed a higher strain hardening exponent when compared to 293 and 473 K. The deformed microstructural features of the compressed and quenched specimens, deformation mechanism, and phase revolution are investigated with X-ray diffraction (XRD) and electron backscattered diffraction (EBSD). Dislocation densities for the deformed conditions were estimated to be 4.11 × 1014 and 5.39 × 1014 m-2 for the 473 and 673 K deformed conditions, respectively. At a deformation temperature of 673 K, B2 precipitation is observed at the high-angle grain boundaries.