Microstructural Development and Mechanical Properties of Selective Laser Melted Co–Cr–W Dental Alloy

Dental restorations are a predestined area for additive manufacturing, due to the required fast fabrication, the low quantities, and the freedom in geometrical designs. Past studies revealed that there is a significant difference in the microstructure compared to traditional investment cast restorations, with drastic implications on the material properties. In many instances, these changes are beneficial, i.e. higher mechanical strength and increased ductility, but at a reduced elastic stiffness. The latter is crucial for the type 5 classification and, based on the studies on a selective laser melted Co–Cr–W dental alloy, a post-heat treatment is inevitable to safely exceed the 150 GPa minimum requirement. Heat treatment at 1150 °C caused a recrystallization and a formation of tungsten rich precipitates, surrounded by a tungsten depleted cobalt–chromium matrix. In the heat-treated state, the alloy exhibited semi-isotropic tensile properties with an average Young’s modulus of about 200 GPa, safely meeting the dental type 2 to 5 classifications.