Microstructure and Wear Behavior of the High-Velocity-Oxygen-Fuel Sprayed and Spark Plasma Sintered High-Entropy Alloy AlCrFeCoNi

Abstract

High-entropy alloy AlCrFeCoNi powder with a metastable body centered cubic (bcc) structure is produced by inert gas atomization. This state is largely preserved after processing the powder by high-velocity-oxygen-fuel (HVOF) thermal spraying. A heat treatment is conducted with the objective to form a duplex structure comprising a ductile face centered cubic (fcc) phase. The formation of an additional fcc phase is accompanied by a decrease in hardness and a significant improvement of wear resistance. The alternative processing route, spark plasma sintering (SPS), causes a duplex bcc and fcc structure. Detailed analyses of phase formation and wear behavior for all production routes contribute to a better understanding of microstructural effects in high-entropy alloys.