Ti6Al4V scaffolds were printed by Direct Ink Writing of a water-based polymeric ink. Different geometries were fabricated in terms of filament size (250 μm, 400 μm and 800 μm) and filament distance (half, same and double the filament size). The designed and actual porosity (total, open and closed), the linear and volumetric shrinkage as well as the microstructure of the scaffolds after sintering were analyzed. The good fitting between designed and actual values of porosity were confirmed both by He-Pycnometry and X-ray micro computed tomography measurements. Results showed that shrinkage decreased with increasing the filament distance over filament size ratio. The microstructure of the scaffolds depended on filament size, showing multiple phases formation for the smallest filament size. The compressive strength behavior was studied experimentally and by computational simulations: the discrepancy between experimental and predicted values of stress-strain compression curves were reflecting the lamellar and acicular phase formation in scaffolds with strut size smaller than 400 μm, whilst they showed a good fitting for scaffolds possessing an equiaxic microstructure.
The effect of strut size on microstructure and compressive strength of porous Ti6Al4V lattices printed via Direct Ink Writing
Elsayed H.;Zanini F.;Carmignato S.;Biasetto L.
2020
Abstract
Ti6Al4V scaffolds were printed by Direct Ink Writing of a water-based polymeric ink. Different geometries were fabricated in terms of filament size (250 μm, 400 μm and 800 μm) and filament distance (half, same and double the filament size). The designed and actual porosity (total, open and closed), the linear and volumetric shrinkage as well as the microstructure of the scaffolds after sintering were analyzed. The good fitting between designed and actual values of porosity were confirmed both by He-Pycnometry and X-ray micro computed tomography measurements. Results showed that shrinkage decreased with increasing the filament distance over filament size ratio. The microstructure of the scaffolds depended on filament size, showing multiple phases formation for the smallest filament size. The compressive strength behavior was studied experimentally and by computational simulations: the discrepancy between experimental and predicted values of stress-strain compression curves were reflecting the lamellar and acicular phase formation in scaffolds with strut size smaller than 400 μm, whilst they showed a good fitting for scaffolds possessing an equiaxic microstructure.
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