Study of the elastoplastic, wear and electrochemical response of cast Ti17NbxHf alloy for potential biomedical applications

In the present work the Ti17Nb x Hf alloys have been studied. Alloys with Hafnium additions (6, 7, 12, and 18 at. %) were obtained by arc melting. The structure of the alloys was identified by XRD tests, while the microstructure was studied by FE-SEM. Instrumented indentation tests were also conducted to determine the elastoplastic properties of the alloys. Dry linear reciprocating wear tests were carried out to establish the tribological response. The corrosion resistance was evaluated by means of electrochemical techniques. The addition of Hf exhibits a phase transformation in the TiNb x Hf alloys from α’’+β-Ti to β-Ti phase derived from the composition and the rapid cooling process, confirmed by XRD and FE-SEM micrographs. The nanoindentation tests indicated maximum hardness values of 3.7 GPa (for the 7 at. % of Hf sample), while a significant reduction in Young's modulus, reaching up to 83 % for the 18 at. % of Hf (52.02 ± 2.41 GPa), was observed when compared to 6 at. % sample (95.14 ± 2.16 GPa). The tribological tests revealed that the Ti17Nb18Hf alloy has the highest wear resistance (4.37 and 29.46 × 10 −13 m 3 /N⋅m, wear rate) and decreases the coefficient of friction (CoF) 0.60 ± 0.04 and 0.58 ± 0.03 for the 7 and 18 at. % of Hf, respectively. The wear mechanisms were mostly identified as adhesion and abrasion. The electrochemical experiments demonstrated that the alloy containing 18 at. % of Hf exhibited the lowest corrosion rate of all the alloys (0.999 ± 0.05 × 10 −4 mm-Y −1 ), resulting in values that fall within the acceptable range for biomedical applications. The results obtained have led to the identification of potentially applicable materials for the biomedical industry. • The elastoplastic properties, wear resistance, and electrochemical corrosion resistance of a Ti17Nb x Hf alloy were investigated. • The incorporation of Hf, in conjunction with the selected processing method, has been demonstrated to facilitate the stabilization of the β-Ti phase within the structure and microstructure. • The elastoplastic properties exhibited a change in response to the stabilization of the β-Ti phase. • The findings indicated that the maximum Hf content exhibited a positive impact on both electrochemical performance and wear resistance. • The Ti17Nb18Hf alloy exhibits a low modulus of elasticity, commendable wear resistance, and exceptional corrosion resistance, thereby augmenting its suitability for biomedical applications.