Multiscale and Multilevel Composite of Solidified TiC-TiB2 with Ti-6Al-4V Achieved by Fusion Bonding in High-Gravity Field

Abstract

By putting Ti-6Al-4V plate at the bottom of the blend of (Ti+B4C) and the high-energy thermit, a novel laminated composite of TiC-TiB2 ceramic to Ti alloy is achieved by combustion synthesis in high-gravity field, and within the joint there presents multiscale and multilevel microstructures characterized by size and distribution of TiB2 and TiB phases, thereby showing microstructure evolution rather than a clear interface from the ceramic to Ti alloy. The reasons for the unique microstructures in the joint came is considered a result of fusion bonding and atomic interdiffusion between liquid TiC-TiB2 and liquid Ti in thermal vacuum circumstances, followed by a series of metallurgical reaction including peritectic reaction of TiB2 solid and Ti liquid, direct growth of TiB from Ti liquid and subsequent eutectic reaction of TiB and Ti, so a continuously-graded microstructure consisting of the multiphases in size from micrometer to nanometer is eatablieshed in the joint.