Processing and characterization of Ti–B-based functionally graded materials produced by microwave-activated combustion synthesis

Abstract

Single as well as graded compositions were fabricated in the Ti–B system using a microwave-activated combustion synthesis (MACS) process. When synergistically combined with microwave processing, combustion synthesis offers great potential for the fabrication of ceramic structures and composites. Combustion waves were triggered using a SiC susceptor to initially absorb microwaves. The effects of processing variables, such as thermal insulation, and atmosphere on the process were investigated. Examination of reacted samples by means of x-ray diffraction indicated the presence of titanium monoboride and diboride along with unreacted titanium. Compared with conventional combustion synthesized products, MACS resulted in smaller pores. However, the total amount of porosity remained almost the same. The microstructure of the graded layers and interfaces were examined using optical and scanning electron microscopy. Over the entire cross section, the interfaces were continuous and crack free.