Calculation of activity of molten titanium alloys and interface reaction with mold materials

On the basis of the Miedema model on the formation heat of alloys and the thermodynamics of chemical reactions and solutions, the activity of molten titanium alloys was calculated. As a comparison, the interface reactivity of some refractory oxides with Ti6Al4V and Ti15V3Cr3Sn3Al alloys has been also studied experimentally. The results show that the chemical reactivity of molten titanium has not been changed due to the addition of alloying elements. The selected molding materials have contaminated the candidate alloys seriously, and the experiment results fit in well with the calculated results. Furthermore, considering the high chemical reactivity of molten titanium alloy, the above evaluations can provide some instructions for choosing mold materials for titanium castings.