Abstract
Purpose: The aim of present work was to investigate microstructure and mechanical properties of 3D printed by selective laser melting (SLM) Co-Cr alloys, intended for additive manufacturing in dentistry.
Methods: A scanning electron microscope (SEM), equipped with an integrated Energy-Dispersive X-Ray Spectroscopy (EDS) system was used for investigation of the surface morphology and elemental composition of the 3D-printed Co-Cr sample. The X-ray structural analysis of the 3D-printed Co-Cr sample was made with a Bruker D8 Advance powder X-ray diffractometer. An atomic force microscopy (AFM) was used to investigate the surface topography of the sample. Tensile test, a three-point bending test and nanoindentation experiments were conducted for investigation of mechanical properties of the 3D-printed Co-Cr sample. The influence of two different strain rates (1 mm/min and 60 mm/min) on the flexural strength was investigated as well.
Results: Higher values of indentation hardness (6.76 GPa), tensile strength (1016 MPa), yield strength (636.5 MPa) and flexural strength (1908 and 1891 MPa) of the Co-Cr alloys produced with the use of selective laser melting have been obtained, compared to cast Co-Cr and Cr-Ni alloys. It was found that increasing the strain rate from 1 mm/min to 60 mm/min caused a proportional decrease in recorded flexural strength of ~0.9%.
Conclusions: The obtained results showed that the laser-sintered Co-Cr alloy can fully replace the cast Co-Cr alloy in dentistry, regarding its good mechanics properties as well as the high precision of the final product.