Effect of NiCoFeAlTi high entropy intermetallic reinforcement particle size on the microstructure and mechanical properties of CoCrFeMnNi high-entropy alloy composites fabricated by selective laser melting

Abstract

The particle size of the reinforcement affects the microstructure and mechanical properties of the composites fabricated by selective laser melting. The powder bed characteristics were greatly influenced by the size of the powder particles. In this research, CoCrFeMnNi high entropy alloys (HEAs) were reinforced with NiCoFeAlTi high entropy intermetallics (HEI) where two different reinforcement sizes were utilized. The microstructure and mechanical properties of CoCrFeMnNi HEA matrix with NiCoFeAlTi HEI reinforcement with varying particle sizes were investigated systematically. The composites reinforced with fine particle size exhibit stress-induced intergranular cracking, element segregation, and poor mechanical properties. On the other hand, composites reinforced with coarser particle size display crack and pore-free microstructure with uniform compositional distribution and relatively outstanding mechanical properties. This work contributes to a further understanding of the influence of reinforcement particle size on the crack-sensitive composites fabricated by selective laser melting.