ABSTRACT
In this work, two different cellular solid structures, obtained by EBM using grade 2 Titanium powders, were investigated. Relative density was evaluated comparing different methods, the mean diameter of the singular open porosity was calculated by SEM image post-processing; the chemical composition was evaluated using Energy Dispersive X-Ray Spectroscopy (EDXS); the microstructure and grain dimension were investigated using chemical etching and, the mechanical properties were investigated using UMTS 810 Materials Test System. The mean porosity values resulted to be similar to spongy bone (around 77% for sample A and 89% for sample B). The mean diameter of the single porosity resulted to be 640 µm for A and 1250 µm for B. The Vickers microhardness results were homogeneous among the structure and the chemical etching showed a complex microstructure characterized by irregular shaped grains. Sample A, as expected, is more resistant than sample B, while sample B shows a lower elastic modulus.
Subject(s)
Titanium/chemistry , Biocompatible Materials , Microscopy, Electron, Scanning , PowdersABSTRACT
EBM (Electron Beam Melting) technology can be used successfully to obtain cellular solids in metallic biomaterials that can greatly increase osseointegration in arthroprothesis and at the same time maintain good mechanical properties. The investigated structures, called Trabecular Titanium, usually cannot be obtained by traditional machining. Two samples: (A) with a smaller single cell area and, (B) with a bigger single cell area, were produced and studied in this project. They have been completely characterized and compared with the results in similar literature pertinent to Ti6Al4V EBM structures. Relative density was evaluated using different methods, the mean diameter of the open porosities was calculated by Scanning Electron Microscope images; the composition was evaluated using Energy-Dispersive X-Ray Spectroscopy; the microstructure (alpha-beta) was investigated using chemical etching and, the mechanical proprieties were investigated using UMTS. The mean porosity values resulted comparable with spongy bone (63% for A and 72% for B). The mean diameter of the single porosity (650 mum for A and 1400 mum for B) resulted compatible with the osseointegration data from the literature, in particular for sample A. The Vickers micro-hardness tests and the chemical etching demonstrated that the structure is fine, uniform and well distributed. The mechanical test proved that sample (A) was more resistant than sample (B), but sample (B) showed an elastic modulus almost equal to the value of spongy bone. The results of this study suggest that the two Ti6Al4V cellular solids can be used in biomedical applications to promote osseointegration demonstrating that they maybe successfully used in prosthetic implants. Additional implant results will be published in the near future.
