Multiscale modeling of titanium investment cast dental prostheses

Titanium alloys are attractive materials for biomedical applications due to their superior biocompatibility. However, the use of titanium alloys for dental and maxillofacial prostheses is particularly challenging because each prosthesis has a unique, complex shape. A multiscale model for the processing of Ti prostheses was developed that combines a commercial macrocode for process simulation with an in-house code to explicitly track the development of the microstructure including surface reactions. The model was applied to simulate the dental titanium investment casting process. The macroscopic heat transfer model is coupled with a microscale simulation incorporating the release and diffusion of impurity elements at the mold-metal interface. The penetration depth of impurity species was simulated to determine the amount of alpha-case formed. The microstructural modeling results indicate that the critical factor is the time for which liquid Ti is in contact with the mold and that the incorporation of silicon from the mold increases this time by depressing the solidus temperature.