Alloy Design and Fabrication of Duplex Titanium-Based Alloys by Spark Plasma Sintering for Biomedical Implant Applications

Abstract

Very often, pure Ti and (α + β) Ti-6Al-4V alloys have been used commercially for implant applications, but ensuring their chemical, mechanical, and biological biocompatibility is always a serious concern for sustaining the long-term efficacy of implants. Therefore, there has always been a great quest to explore new biomedical alloying systems that can offer substantial beneficial effects in tailoring a balance between the mechanical properties and biocompatibility of implantable medical devices. With a view to the mechanical performance, this study focused on designing a Ti-15Zr-2Ta-xSn (where x = 4, 6, 8) alloying system with high strength and low Young’s modulus prepared by a powder metallurgy method. The experimental results showed that mechanical alloying, followed by spark plasma sintering, produced a fully consolidated (α + β) Ti-Zr-Ta-Sn-based alloy with a fine grain size and a relative density greater than 99%. Nevertheless, the shape, size, and distribution of α-phase precipitations were found to be sensitive to Sn contents. The addition of Sn also increased the α/β transus temperature of the alloy. For example, as the Sn content was increased from 4 wt.% to 8 wt.%, the β grains transformed into diverse morphological characteristics, namely, a thin-grain-boundary α phase (αGB), lamellar α colonies, and acicular αs precipitates and very low residual porosity during subsequent cooling after the spark plasma sintering procedure, which is consistent with the relative density results. Among the prepared alloys, Ti-15Zr-2Ta-8Sn exhibited the highest hardness (s340 HV), compressive yield strength (~1056 MPa), and maximum compressive strength (~1470). The formation of intriguing precipitate–matrix interfaces (α/β) acting as dislocation barriers is proposed to be the main reason for the high strength of the Ti-15Zr-2Ta-8Sn alloy. Finally, based on mechanical and structural properties, it is envisaged that our developed alloys will be promising for indwelling implant applications.

Finite Element Modelling of a Synthetic Paediatric Spine for Biomechanical Investigation

“…Accordingly, these findings suggested that the synthetic paediatric disc fabricated in the synthetic paediatric spine was acceptable. Here, we also envisage that the beta titanium alloys having advantageous mechanical properties that could serve promising potential for the fabrication of paediatric spines and other biomedical devices [ 27 , 28 , 29 , 30 ].…”

Antimicrobial Properties of TiNbSn Alloys Anodized in a Sulfuric Acid Electrolyte

“…There are other reports on biocompatible titanium alloys with a low Young’s modulus besides TiNbSn alloys [ 7 , 8 , 9 , 10 , 11 ]. TiNbSn alloys have been clinically applied in hip replacement stems.…”

“…In clinical practice, the difference in the Young’s moduli of implants and the human cortical bone leads to a disproportionate stress distribution, resulting in pain and bone atrophy after surgery [ 6 ]. To resolve this problem, new titanium alloys, such as TiMoZrTa, TiMoZrSi, and TiZrTaSn alloys, have been developed that possess a low Young’s modulus in combination with biocompatibility and strength, and they have shown excellent material properties and favorable results in preclinical studies have been reported [ 7 , 8 , 9 , 10 , 11 ]. In our institute, the development of a near-β-type TiNbSn alloy with a low Young’s modulus of <50 GPa was speculated to reduce stress shielding and thigh pain [ 12 ].…”

Corrosion Passivation in Simulated Body Fluid of Ti-Zr-Ta-xSn Alloys as Biomedical Materials

“…Ti-based alloys are significant for many different applications in addition to biomedicine, for example, in the automotive and aerospace industries. Their outstanding biocompatibility, extraordinary corrosion resistance, and high mechanical strength allow these alloys to be successfully used in biomedical applications [ 5 , 6 , 7 , 8 , 9 , 10 ].…”

“…Although the titanium–aluminum–vanadium (Ti-6Al-4V) alloy has long been employed in such applications, the V and Al released from the alloy could have harmful effects [ 7 , 8 , 9 , 10 , 11 , 12 ]. Al +3 and V +5 are released as free radicals, interact with the bloodstream, and possibly trigger harmful responses in humans, which increases the risk of developing Alzheimer’s disease [ 13 , 14 , 15 , 16 , 17 ].…”