Wetting and interfacial behavior of Al–Ti/4H–SiC system:A combined study of experiment and DFT simulation

Abstract Wetting and interfacial behavior of molten Al-(10, 20, 30, 40) at.%Ti alloys on C-terminated 4H–SiC at 1500 and 1550 °C were investigated experimentally, and theoretical bonding strength, structure stability and electronic structure of interfacial reaction products/C-terminated 4H–SiC interfaces were evaluated by first-principle calculations. The wetting experiments show that the Al–Ti/SiC systems present excellent wettability with contact angle of less than 15° except the Al–40Ti/SiC system performed at 1500 °C × 30 min. The SEM-EDS and TEM analyses demonstrate that the reaction products are mainly composed of Al4C3, TiC, Ti3SiC2, Ti5Si3CX and τ phase, and their formation and evolution can be mainly affected by the Ti concentration in the Al–Ti alloys and wetting temperature. Moreover, the calculated results show that the SiC/C-terminated TiC interface presents the highest work of separation and its electronic property reveals that the localization of electrons and formation of covalent bond between interfacial C atoms lead to the excellent bonding strength of SiC/TiC interface.