Microstructural Characterization of Co-Cr-Mo-W Alloy as Casting for Odontological Application

Abstract

Interest in the analysis and material characterization is rising due to the necessity of the adequate material selection based on system performance in study. The analysis and knowledge of the microstructure and the mechanical properties of any material are of utmost importance since it aims primarily to estimate the performance during the material life span, minimizing the possibility of degradation and undesirable flaws during product utilization. Co-Cr-Mo-W alloys have been well accepted in odontology as prosthesis material, due to its high mechanical resistance, good corrosion resistance and exceptional biocompatibility properties. This study aims to characterize the microstructure of a cobalt based alloy (Co-Cr-Mo-W) obtained through vacuum casting process. Optical microscopy, electronic sweeping microscopy and X-ray were employed and Vickers hardness test with loads of 100 gf, 500 gf and 1000 gf during 10 s. Microstructure casting is characterized by a Co-fcc dendritic matrix with a secondary phase, as well as M 23 C 6 precipitate carbides in the interdendritics zones and grain boundaries. The precipitation of carbides represents the main device of strengthening in the cast state for these types of alloys and is also responsible for its lower mechanical properties. The material attained hardness between 25 and 35 HRC, meeting the ASTM F75 standards.