Phase transformation and strengthening of the gas-atomized FeCoCrNiMoAl high-entropy alloy powder during annealing.

Phase evolution and strengthening of the FeNiCoCrMoAl powder alloy produced via inert gas atomization and annealed in the temperature interval of 300-800 °C have been studied by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and microhardness testing. It was found that annealing at 300-600 °C leads to an increase of the element segregations between the several solid solutions with a rise of the lattice misfit to 1.5 % and microhardness growth to 1070 HV.

Oxidation Behavior of FeNiCoCrMoAl High-Entropy Alloy Powder.

One of the most promising applications of FeNiCoCrMoAl-based high-entropy alloy is the fabrication of protective coatings. In this work, gas-atomized powder of FeNiCoCrMoAl composition was deposited via high-velocity oxygen fuel spraying. It was shown that in-flight oxidation of the powder influences the coating's phase composition and properties.

Microstructure Evolution of FeNiCoCrAlMo High Entropy Alloy during Powder Preparation, Laser Powder Bed Fusion, and Microplasma Spraying.

In the present study, powder of FeCoCrNiMoAl HEA was manufactured by gas atomization process, and then used for laser powder bed fusion (L-PBF) and microplasma spraying (MPS) technologies. The processes of phase composition and microstructure transformation during above mentioned processes and subsequent heat treatment were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and differential thermal analysis (DTA) methods. It was found that gas atomization leads to a formation of dendrites of body centered cubic (BCC) supersaturated solid solution with insignificant Mo-rich segregations on the peripheries of the dendrites.