Abstract:An investigation was carried out on the reaction process and mechanism between K2TiF6, graphite powder and aluminum melt with the common Ti concentration of 5%~7% in the grain-refiner Al-Ti-C master alloys and the reaction temperature of 750~950℃, aiming at understanding their reaction mechanism and putting forward the aluminothermal reduction reaction method to practical use. During experimental investigation, K2TiF6and graphite wrapped
in aluminum foils were introduced into the aluminum melt at 850℃. Samples of alloy and slag were investigated by chemical analysis, XRD examination, SEM observation, and EDS analysis as well. It was found that the reaction was very vigorous at the beginning of the process and then reached a dynamic equilibrium. There were 3 particular reactions during the  aluminothermal reaction process. At the beginning stage of the reaction, there emerged the phases of TiC and one type of metastable intermetallic phase TiAl9as well as TiAl3in aluminum melt. At the late stage of the reaction, the metastable phase TiAl9disappeared and another phase of Al4C3emerged.

Key words: Al-Ti-C master alloys; aluminothermal reaction; reaction mech-nism; K2TiF6