EFFECT OF PROCESSING ROUTES ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF NOVEL HIGH ENTROPY ALLOYS

Abstract

High entropy alloys have garnered a lot of attention due to their impressive mechanical properties even at high temperature conditions compared to conventional alloys. In this study the High entropy alloys have been developed through two processing routes to understand the effect different processing conditions have on the resulting properties of the high entropy alloy. Electromagnetic levitation was used to process a NiCoCrNb high entropy alloy at low undercooling to form a high entropy alloy at equilibrium having FCC and Laves phase giving microhardness values of 800HV while Powder metallurgy route was used to make two NiCoCrNb samples at 18 hours of milling with 1050C sintering temperature and 28 hours of milling with 1100C sintering temperature. The 18hr-1050C sample showed improper sintering with high porosity and low densification; this resulted in low hardness values of 120HV. While the 28hr-1100C sample showed higher densification and higher hardness values of around 430HV which showed the formation of an HEA and proper sintering. The significant improvement in properties of the powder metallurgy samples in this study help us conclude that the powder metallurgy route offers promising results in improving the mechanical properties of the high entropy alloy with slight changes in processing parameter.