Thermal stability, microstructure and texture evolution of thermomechanical processed AlCoCrFeNi2.1 eutectic high entropy alloy

The microstructural and texture evolutions of as-cast AlCoCrFeNi2.1 eutectic high entropy alloy (EHEA) have been investigated in the course of thermomechanical processing at the temperature range of 25-500 degrees C. Inter-estingly, compared with other conventional casting structures, significant strength-ductility ratio has been achieved at room temperature. In addition, the volume fractions of the constituent phases: soft FCC (face centered cubic), and the hard BCC (body-centered cubic) phases, do not significantly change from room to elevated deformation temperatures. In fact, the strength and ductility have not been decreased at higher temperatures which represent the mechanical stability of the alloy in the examined temperature range. From room temperature up to 300 degrees C, the dendrites have been stretched and broken with a slight deviation from the load direction, whereas at higher temperature of 500 degrees C the dendrites have been rotated relative to the direction of load before fracture. Texture examination reveals the formation of a random texture in the initial and deformed states due to simultaneous contribution of different influencing factors such as stretching of dendrites during deformation, the dendrite morphology changes, and the presence of hard and soft phases and their interaction with each other.

Automated summary

The microstructural and textural evolutions of as-cast high entropy alloy were investigated during thermomechanical processing at temperatures ranging from 25 to 500 degrees Celsius. The alloy exhibited significant strength-ductility ratio at room temperature and maintained mechanical stability at elevated temperatures. The volume fractions of constituent phases and the texture of the alloy were found to be consistent across different deformation temperatures.