Microstructural Characterization of Mechanically Alloyed FeCoNiMnV High Entropy Alloy Consolidated by Spark Plasma Sintering.

The microstructure and phase evolution of the mechanically alloyed FeCoNiMnV high entropy alloy during spark plasma sintering are examined. The milled powders are sintered at different temperatures ranging between 500 °C and 1000 °C. A multiphase structure is produced during the sintering process. The produced alloy experiences different types of decompositions and phase formations as the sintering temperature is raised. During sintering at different temperatures, the body centered cubic and face centered cubic (FCC) phases are transformed to new FCC and tetragonal phases. According to the results, V does not show the tendency to dissolve into the structure and the tetragonal phases, mainly composed of V and Mn, tending to be formed in addition to the FCC solid solution. Sintering at 900 °C results in the grain size of about 220 nm, attaining the highest hardness of about 450 HV. The sintered alloy at 1000 °C shows the highest relative density (about 98%) with an average grain size of about 580 nm. The phase formation is predicted and evaluated by different criteria, and the consistency between the theoretical and experimental results is explained. [ABSTRACT FROM AUTHOR]