The application of
titanium alloy in dentistry has been a hot topic in recent years. High niobium titanium alloy has attracted much attention because of its low elastic modulus and good mechanical strength. Casting is a common dental processing method. The casting flow rate is a comprehensive reflection of alloy properties, casting equipment and casting conditions, which is one of the important indicators to evaluate the feasibility of the casting system in clinical application. The casting fillability of titanium alloy is related to the type and amount of alloying elements. The high niobium-titanium、niobium-zirconium-tin [Ti-24Nb-4Zr-7.6Sn (wt%})] alloy was studied. The feasibility of high niobium-titanium alloy in casting processing was discussed by evaluating the casting flow rate using mesh sample method. It also provides reasonable casting parameters for dental application.
At the same time of the development of the new titanium alloy, the application of the alloy in the field of oral cavity is also being studied. Investment casting is still the mainstream processing method of dental materials, so casting flow rate is an important index to evaluate the properties of alloys. Filling property is one of the main criteria for selecting alloys for precision casting. The addition of
niobium in high niobium titanium alloy has a significant effect on the filling property of titanium alloy. The thin section of the casting is filled with an exact replica of the sharp edges to a large extent. It depends on capillary action. Therefore, the surface tension of liquid metal and the wettability of casting mold are two important factors that determine the filling property. The surface tension of liquid titanium shows that the higher the content of niobium in titanium alloy, the higher the surface tension. Meanwhile, the wetting Angle of titanium solution deteriorates with the increase of niobium element. This is an important reason for the relatively poor flow rate of high niobium titanium alloy. The casting flow rate of Ti-Nb-Zr-Sn alloy is low due to the addition of niobium.
In addition, the casting temperature has a great influence on the casting flow rate of titanium alloy. The fluidity of titanium solution can be increased by increasing the casting temperature. When the temperature difference between the casting temperature and molten titanium solution is large, the alloy will solidify quickly in the cavity, which will reduce the final casting flow rate of the alloy, and vice versa. The Ti-Nb-Zr-Sn alloy also exhibits such properties. The flow rate of the alloy cast at room temperature and 300C is significantly lower than that of the 600C group, indicating that the increase of casting temperature can increase the flow rate of titanium alloy cast. Therefore, in order to ensure the integrity of clinical denture castings, the casting temperature of Ti-Nb-Zr-Sn alloy should be selected above 600 C.
