Microstructure, mechanical properties, and corrosion behavior of TiVNbZrHf high entropy alloys fabricated by multi-step spark plasma sintering

Abstract

The primary objective of this study was to produce a TiVNbZrHf high-entropy alloy through powder metallurgy process and characterize its properties. The effect of sintering temperature on the microstructure and mechanical properties of bulk TiVNbZrHf samples was investigated. The resulting microstructure of the bulk samples included two different phase structures: a body-centered cubic (BCC) phase with a composition rich in (Ti-V-Nb)-Hf and a hexagonal close-packed (HCP) phase with a composition rich in (Hf-Zr)-Ti. The particle size and relative density of the bulk sample increased with the rising sintering temperature. The bulk TiVNbZrHf sample exhibited the highest hardness and the lowest wear rate when sintered at 1400 °C. The corrosion resistance of the bulk samples submerged in a 3.5 wt% NaCl solution steadily improved with increasing sintering temperatures. This improvement is attributed to the increased relative density and diminished grain boundaries. Our research highlights the crucial role of precise temperature control during the sintering process to achieve the desired material properties of high-entropy alloys.