Process for reducing reaction of directional solidification titanium-aluminum alloy castings and casting mold coatings

The invention researches a process for reducing the reaction of directional solidification titanium-aluminum alloy castings and casting mold coatings, and belongs to a directional solidification casting method of a high-temperature structural alloy. The invention aims at providing optimal process parameters during titanium-aluminum alloy preparation achieved through directional solidification, the interface reaction between an alloy melt and casting mold materials is weakened to be minimum when the heat preservation time is 30 minutes and the drawing speed is 60 micrometers per second by means of design of directional solidification parameters of a Ti-48Al-7Nb-2.5V-1.0Cr alloy, the reaction layer thickness is reduced to be less than 10 micrometers, the surfaces of the castings are smooth, and internal contamination is little. The process is characterized in that the time of contact between the melt and casting molds is shortened, and the problems that when the drawing speed is high, the number of crystalline