Researchers highlight porous Ti6Al4V materials for bioimplants
Researchers from Mexican institutions Universidad Michoacana de San Nicolás de Hidalgo, Tecnológico Nacional de México, and Universidad Autónoma de Coahuila, along with France’s University Grenoble Alps, recently published a study in Materials on the tailoring of porous Ti6AL4V for biomedical purposes.
As metallic bone replacements are in increasingly high demand, implants must have more tailored properties to ensure their long-term use in the human body. ‘Development of Tailored Porous Ti6Al4V Materials by Extrusion 3D Printing’ sought to develop components with the necessary characteristics via Additive Manufacturing.
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Using Metal Injection Molding (MIM) pellet feedstock, the researchers additively manufactured hexagonal channels of three different sizes. The densification kinetics were then evaluated by dilatometry tests before the parts were sintered. After post-processing, the samples were characterised by scanning electron microscopy (SEM) and X-ray computed tomography to analyse their respective microstructures. Compression tests were used to evaluate the parts’ mechanical strength.
The researchers found that the hexagonal shape was better defined as the channel size increased. The results showed similar behaviour for each of the channel sizes during sintering; however, greater densification was obtained as the channel size decreased. Additionally, microporosity was obtained at the particle level, which is completely interconnected, ensuring the passage of fluids through the entire sample. As the channel size increased, however, Young’s modulus and yield strength were considerably reduced. The main conclusion is that parts with two scales of porosity can be achieved by Additive Manufacturing.
Permeability values were shown to be in the range of trabecular bones, which the researchers noted as promising for the osseointegration of such materials. The mechanical properties are a little higher in comparison to those of trabecular bones, but these are properties which can be tuned by increasing the pore volume fraction during the manufacturing stage.
Evaluation of cell attachment and bone ingrowth with this kind of sample is in progress to determine what size will be the most effective. This is expected to lead to the fabrication of bone implants like hip, knees or vertebral implants, with the best size and configuration of channels and tailored porosity according to requirements.
‘Development of Tailored Porous Ti6Al4V Materials by Extrusion 3D Printing’ is available here.
www.mdpi.com/journal/materials
