Nanostructured Al–Ti–Fe–Mn–Ni High-Entropy Alloy by Mechanical Alloying: Synthesis and Characterization

A multicomponent bulk nanostructured Al₂₀Ti₂₀Fe₂₀Mn₂₀Ni₂₀ high-entropy alloy (HEA) was prepared by the powder metallurgy method. The process involved mechanical alloying of the elemental powders of equal wt% followed by cold compaction and conventional sintering in an inert atmosphere at different temperatures. The structural evaluation and morphological studies of the milled powders were carried out by HRTEM and XRD analysis. The crystal size and d-spacing of the milled powder significantly reduced with the milling duration. The effects of sintering temperatures on the microstructure, wear resistance, and the hardness of Al₂₀Ti₂₀Fe₂₀Mn₂₀Ni₂₀ were investigated. The microstructural analysis showed that the prepared HEAs had a multiphase microstructure consisting of BCC and intermetallic compounds. As the sintering temperature grew, the microhardness and wear resistance increased, demonstrating that the properties of the current HEA were improved by using high sintering temperatures. The increase in density with sintering temperatures and the intermetallic phase contents acted as reinforcement might have enhanced the hardness of the HEA. The best hardness value and the least amount of wear were found in the sample sintered at 900 °C.