Characterization of TiCrMoZr (Nb/Mn) Complex Concentrated Alloys Synthesized by Vacuum Arc Melting

Abstract Complex concentrated alloys (CCAs) have attracted significant attention due to their unique microstructures and outstanding mechanical and thermal properties. In this study, TiCrMoZrNb (Nb20-CCA) and TiCrMoZrMn (Mn20-CCA) were prepared using a vacuum arc melting technique to ensure uniform composition and minimize contamination. The phase composition and microstructure were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Mechanical properties, including hardness, fracture toughness, and wear resistance, were evaluated. Young’s modulus was also measured using the pulse-echo ultrasonic technique. Corrosion behavior was assessed using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in saline solution with hydroxyapatite (HA) additions (up to 3.0 g). Thermodynamic calculations indicated that both Nb20-CCAs and Mn20-CCAs are high-entropy CCAs. Young's modulus of the two alloys ranged between 87 and 93 GPa, which is suitable for reducing stress shielding in orthopedic implants. Mechanical investigation showed that both alloys exhibit comparable hardness, despite their different elemental compositions. Wear tests confirmed the superior tribological performance for Nb20-CCAs, which exhibited significantly lower weight loss and specific wear rate than Mn20-CCAs. Electrochemical evaluations showed that both alloys have good corrosion resistance. However, Nb20-CCAs outperformed Mn20-CCAs, particularly when modified with HA, with PDP showing the lowest corrosion rate at a 3 g HA, while EIS indicated that the 0 g HA provided the highest resistance. The overall results demonstrated that compositional design plays a crucial role in enhancing the functional performance of Ti-based CCAs for potential biomedical applications. Graphical Abstract