Experimental Investigation of the Impact of Niobium Additions on the Structural Characteristics and Properties of Ti–5Cr–xNb Alloys for Biomedical Applications

Abstract

In this study, a series of Ti–5Cr–xNb alloys with varying Nb content (ranging from 1 to 40 wt.%) were investigated to assess their suitability as implant materials. Comprehensive analyses were conducted, including phase analysis, microscopy examination, mechanical testing, and corrosion resistance evaluation. The results revealed significant structural alterations attributed to Nb addition, notably suppressing the formation of the ω phase and transitioning from α’ + β + ω to single β phase structures. Moreover, the incorporation of Nb markedly improved the alloys’ plastic deformation ability and reduced their elastic modulus. In particular, the Ti–5Cr–25Nb alloy demonstrated high values in corrosion potential and polarization resistance, signifying exceptional corrosion resistance. This alloy also displayed high bending strength (approximately 1500 MPa), a low elastic modulus (approximately 80 GPa), and outstanding elastic recovery and plastic deformation capabilities. These aggregate outcomes indicate the promising potential of the β-phase Ti–5Cr–25Nb alloy for applications in orthopedic and dental implants.

Structure and Properties of Metastable β Ti–25Nb–8Sn Alloy following Cold Rolling and Aging Treatments

“…Three-point bending tests were performed by using a desktop universal testing machine (HT-2102AP; Hung Ta Instrument, Taichung, Taiwan) at a crosshead speed of 0.5 mm/min, with a span length of 30 mm and a maximum deflection distance of 8 mm. The bending strength (σ) was determined by using the formula σ = 3PL 2bh 2 [14], where P denotes the applied load (N), L is the span length (mm), b is the width of the specimen (mm), and h is the thickness of the specimen (mm). Furthermore, the elastic modulus (E) was calculated with the equation E = PL 3 4bh 3 ∆δ [14], where ∆δ indicates the load displacement.…”

“…The bending strength (σ) was determined by using the formula σ = 3PL 2bh 2 [14], where P denotes the applied load (N), L is the span length (mm), b is the width of the specimen (mm), and h is the thickness of the specimen (mm). Furthermore, the elastic modulus (E) was calculated with the equation E = PL 3 4bh 3 ∆δ [14], where ∆δ indicates the load displacement. The elastic admissible strain (EAS) was calculated by using the equation EAS = σ y E [15], where σ y represents the yield strength (MPa) and E denotes the elastic modulus (GPa).…”

“…Subsequently, upon removal of the load, the sample underwent elastic deformation, resulting in a deflection angle denoted by θ 2 . The elastic recovery angle of the alloy was determined by subtracting θ 2 from θ 1 , with details reported in a previous study [14]. Fracture surfaces of broken samples were examined by using a scanning electron microscope (SEM; S-4800; Hitachi, Tokyo, Japan).…”