Production of Al-Ti-B Grain Refining Master Alloys from B_2O_3 and K_2TiF_6 by Microwave Irradiation

摘要

Al-Ti-B master alloys have received much attention in recent years owing to their potential as efficient grain refiners for aluminum foundry alloys. A process involving in-situ reduction of K_2TiF_6 and B_2O_3 with excess aluminum in the presence of cryolite flux has been developed for the preparation of Al-Ti-B master alloys using a melt reaction method by microwave irradiation. The microstructure and synthetic process of the master alloy were investigated by optical microscopy and X-ray diffraction. The results show that themicrowave irradiation method can be used to fabricate Al-Ti-B master alloy in situ from the K_2Ti_F_6-B_2O_3-Na_3AlF_6 and Al system when the aluminum melted. The synthesis mechanisms of the master alloy are as follows: Al_3Ti is formed through the reaction between K_2TiF_6 and Al melt at 850°C.