Tailoring Phase Stability and Mechanical Properties in TiZrNb-Based HEAs through Elemental Substitution

This study investigates the microstructural and mechanical properties of three high-entropy alloys—TiZrNbCrV, TiZrNbFeCr, and TiZrNbFeV synthesized via mechanical alloying. The alloy powders were subsequently compacted under a pressure of 2000 MPa and sintered at 1150 °C for 1 h in an argon–hydrogen atmosphere.The produced alloys were characterized using X-ray diffraction (XRD), differential thermal analysis (DTA), field-emission scanning electron microscopy (FE-SEM), Vickers microhardness testing, and compressive strength measurements. Among the investigated compositions, TiZrNbCrV exhibited the highest compressive strength (1055 MPa), whereas TiZrNbFeCr showed the lowest fraction of hexagonal close-packed (HCP) and intermetallic phases. In contrast, TiZrNbFeV contained the highest proportion of minor phases and demonstrated the lowest mechanical efficiency. These results highlight the significant role of alloying elements and processing conditions in governing phase evolution and mechanical performance in high-entropy alloys (HEAs). These alloys are investigated as TiZrNb-based HEAs with compositional modifications aimed at tuning phase stability and mechanical behavior. Although Ti, Zr, and Nb are well-known biocompatible elements, this study does not evaluate biomedical performance. • Three novel TiZrNb-based Bio-HEAs (TiZrNbCrV, TiZrNbFeCr, TiZrNbFeV) successfully fabricated via mechanical alloying and powder metallurgy route. • TiZrNbCrV exhibits predominant BCC phase with the highest compressive strength of 1055 MPa, hardness of 361 HV and lowest porosity of 3.11%. • Elemental substitution of Fe/V for Cr significantly affects phase stability: TiZrNbFeCr shows minimal HCP + intermetallic phases among the three alloys. • All alloys achieve remarkably low Young’s modulus (23.7–24.8 GPa) and porosity-controlled microstructure suitable for load-bearing biomedical implants. • Fractography reveals cleavage-dominated brittle fracture with strong grain boundary cohesion achieved by mechanical alloying and pressure-assisted sintering.