Hooyar Attar

Composition optimization of low modulus and high-strength TiNb-based alloys for biomedical applications

The effect of chemical composition on microstructure and tensile properties of a series of low modulus Ti-Nb-Cu-Ni-Al alloys was studied. These alloys consist of primary micrometer-sized β-Ti dendrites surrounded by intermetallic phases. The morphology of the intermetallic phases is strongly affected by composition. Due to the composite microstructure, the alloys exhibit a low Youngs modulus (77-84GPa) together with a high yield strength of about 1000MPa as well as moderate tensile ductility. The results demonstrate that complete substitution of Al by Ti reduces the Youngs modulus by 5%. Increasing Nb content at the expense of Ti causes a significant improvement of tensile ductility.

Review on manufacture by selective laser melting and properties of titanium based materials for biomedical applications

Titanium (Ti) based materials are deemed one type of the best metallic materials for biomedical application due to their good mechanical properties, high biocompatibility and corrosion resistance. Design and manufacture of complex shape Ti parts with good quality are highly demanded in biomedical areas. Selective laser melting (SLM), an additive manufacturing technology, is able to produce bulk structural parts almost without geometric constraints. This review paper briefly evaluates the work carried out on the significance of Ti materials, SLM technology and SLM manufacturing of Ti materials commonly used for biomedical applications including the microstructures and mechanical properties of resulting bulk dense parts (Ti, Ti–24Nb–4Zr–8Sn, Ti–6Al–4V, Ti–6Al–7Nb, Ti–TiC and Ti–TiB) as well as the porous structures successfully produced by SLM. This review indicates that SLM produced Ti materials are able to fulfill the biomechanical and biocompatibility requirements and can be considered as potential candidate for biomedical applications.

Mechanical properties and biocompatibility of porous titanium scaffolds for bone tissue engineering

Synthetic scaffolds are a highly promising new approach to replace both autografts and allografts to repair and remodel damaged bone tissue. Biocompatible porous titanium scaffold was manufactured through a powder metallurgy approach. Magnesium powder was used as space holder material which was compacted with titanium powder and removed during sintering. Evaluation of the porosity and mechanical properties showed a high level of compatibility with human cortical bone. Interconnectivity between pores is higher than 95% for porosity as low as 30%. The elastic moduli are 44.2GPa, 24.7GPa and 15.4GPa for 30%, 40% and 50% porosity samples which match well to that of natural bone (4-30GPa). The yield strengths for 30% and 40% porosity samples of 221.7MPa and 117MPa are superior to that of human cortical bone (130-180MPa). In-vitro cell culture tests on the scaffold samples using Human Mesenchymal Stem Cells (hMSCs) demonstrated their biocompatibility and indicated osseointegration potential. The scaffolds allowed cells to adhere and spread both on the surface and inside the pore structures. With increasing levels of porosity/interconnectivity, improved cell proliferation is obtained within the pores. It is concluded that samples with 30% porosity exhibit the best biocompatibility. The results suggest that porous titanium scaffolds generated using this manufacturing route have excellent potential for hard tissue engineering applications.

Insights into Machining of a β Titanium Biomedical Alloy from Chip Microstructures

1 School of Science and Engineering, University of the Sunshine Coast, Maroochydore DC, QLD 4558, Australia; dkent@usc.edu.au 2 Queensland Centre for Advanced Materials Processing and Manufacturing (AMPAM), The University of Queensland, St. Lucia, 4072, Australia; d.kent@uq.edu.au (D.K.); m.bermingham@uq.edu.au (M.B.); h.attar@uq.edu.au (H.A.); m.dargusch@uq.edu.au (M.B.) 3 ARC Research Hub for Advanced Manufacturing of Medical Devices, St. Lucia, 4072, Australia 4 School of Engineering, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Victoria 3122, Australia; rrahmanrashid@swin.edu.au (R.R.); ssun@swin.edu.au (S.S.) 5 Defence Materials Technology Centre, Victoria 3122, Australia * Correspondence: dkent@usc.edu.au; Tel.: +61-5456-5267