Synthesis and application of epoxy resins: A review

Review on titanium and titanium based alloys as biomaterials for orthopaedic applications.

Ti-based alloys are finding ever-increasing applications in biomaterials due to their excellent mechanical, physical and biological performance. Nowdays, low modulus β-type Ti-based alloys are still being developed. Meanwhile, porous Ti-based alloys are being developed as an alternative orthopedic implant material, as they can provide good biological fixation through bone tissue ingrowth into the porous network. This paper focuses on recent developments of biomedical Ti-based alloys. It can be divided into four main sections. The first section focuses on the fundamental requirements titanium biomaterial should fulfill and its market and application prospects. This section is followed by discussing basic phases, alloying elements and mechanical properties of low modulus β-type Ti-based alloys. Thermal treatment, grain size, texture and properties in Ti-based alloys and their limitations are dicussed in the third section. Finally, the fourth section reviews the influence of microstructural configurations on mechanical properties of porous Ti-based alloys and all known methods for fabricating porous Ti-based alloys. This section also reviews prospects and challenges of porous Ti-based alloys, emphasizing their current status, future opportunities and obstacles for expanded applications. Overall, efforts have been made to reveal the latest scenario of bulk and porous Ti-based materials for biomedical applications.

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New Developments of Ti-Based Alloys for Biomedical Applications

The design of new low-cost Ti-alloys with high biocompatibility for implant applications, using ubiquitous alloying elements in order to establish the strategic method for suppressing utilization of rare metals, is a challenge To meet the demands of longer human life and implantation in younger patients, the development of novel metallic alloys for biomedical applications is aiming at providing structural materials with excellent chemical, mechanical and biological biocompatibility It is, therefore, likely that the next generation of structural materials for replacing hard human tissue would be of those Ti-alloys that do not contain any of the cytotoxic elements, elements suspected of causing neurological disorders or elements that have allergic effect Among the other mechanical properties, the low Young's modulus alloys have been given a special attention recently, in order to avoid the occurrence of stress shielding after implantation Therefore, many Ti-alloys were developed consisting of biocompatible elements such as Ti, Zr, Nb, Mo, and Ta, and showed excellent mechanical properties including low Young's modulus However, a recent attention was directed towards the development of low cost-alloys that have a minimum amount of the high melting point and high cost rare-earth elements such as Ta, Nb, Mo, and W This comes with substituting these metals with the common low cost, low melting point and biocompatible metals such as Fe, Mn, Sn, and Si, while keeping excellent mechanical properties without deterioration Therefore, the investigation of mechanical and biological biocompatibility of those low-cost Ti-alloys is highly recommended now lead towards commercial alloys with excellent biocompatibility for long-term implantation

Biocompatibility of Ti-alloys for long-term implantation.

Selective electron beam melting (SEBM) belongs to the additive manufacturing technologies which are believed to revolutionise future industrial production. Starting from computer-aided designed data, components are built layer by layer within a powder bed by selectively melting the powder with a high power electron beam. In contrast to selective laser melting (SLM), which can be used for metals, polymers and ceramics, the application field of the electron beam is restricted to metallic components since electric conductivity is required. On the other hand, the electron beam works under vacuum conditions, can be moved at extremely high velocities and a high beam power is available. These features make SEBM especially interesting for the processing of high-performance alloys. The present review describes SEBM with special focus on the relationship between process characteristics, material consolidation and the resulting materials and component properties.

Additive manufacturing of metallic components by selective electron beam melting — a review

Elastic deformation behaviour of Ti-24Nb-4Zr-7.9Sn for biomedical applications

Solid-state reactive diffusion between Ti and Al was investigated in the temperature range of 520-650 degrees C by employing multi-laminated Ti/Al diffusion couples. In samples annealed up to 150 h intermetallic TiAl3 is the only phase observed in the diffusion zone and the preferential formation of this compound in Ti/Al diffusion couples was predicted using an effective heat of formation model. The present work indicated that both Ti and Al diffused into each other and the growth of the TiAl3 layers occurred mainly towards the Al side. The TiAl3 growth changes from parabolic to linear kinetics between 575 and 600 degrees C, characterized by activation energy of 33.2 and 295.8 kJ mol(-1), respectively. It is suggested that the low-temperature kinetics is dominated by the diffusion of Ti atoms along the grain boundaries of the TiAl3 layers, while the reaction at the TiAl3/Al interfaces in the high-temperature regime is limited by the diffusion of Ti atoms in the Al foils as a result of increased solubility of Ti in Al with increasing temperature. (c) 2006 Elsevier B.V. All rights reserved.

Y.L. Hao

Papers

Elastic deformation behaviour of Ti-24Nb-4Zr-7.9Sn for biomedical applications

Growth of intermetallic layer in multi-laminated Ti/Al diffusion couples

Influence of cell shape on mechanical properties of Ti-6Al-4V meshes fabricated by electron beam melting method.

Fatigue properties of a metastable beta-type titanium alloy with reversible phase transformation.

The mechanism of inhibition by zinc phosphate in an epoxy coating