Study on The Dental Castings of Ti-Zr-Mo Alloy

Objectives: The dental castings of Ti-Zr-Mo alloy were investigated in the casting machine specially designed for titanium in order to reveal the application for dental prosthodontic materials. Methods: The influence of the mold temperature on castability and mechanical properties of the Ti-Zr-Mo alloy castings was studied. The microhardness from the surface to the inner part was measured with a Knoop hardness tester. The Micro-structures of the castings at three mold temperatures were observed. Results: The castability was found to be good at various mold temperatures, but the higher the mold temperature during casting, the greater the reaction between Ti-Zr-Mo alloy casting surface and the investment. In the tensile strength test of Ti-Zr-Mo alloy castings, the tensile strength and yield strength values increased and the elongation values decreased with the raising in mold temperature. From the optical micrographs observation of the surface reaction layer on Ti-Zr-Mo alloy castings, a reactive layer whose thickness increases with higher mold temperature was observed. The Knoop hardness in the surface reacted layer was greater than that in the inner part. At a higher mold temperature the thickness of the reactive layer was increased. The castings microstructure showed mainly ¦Á phase and finer crystal grains than pure titanium castings. Conclusion: All the results above suggest that Ti-Zr-Mo alloy as a dental material can satisfy the requirement of castability and mechanical properties. The optimal mold temperature for Ti-Zr-Mo alloy casting is about 300 Centigrade.This work was supported by National Science Foundation of China, Grant30171022.