Structural design of laminated B4C/TiC composite fabricated by reactive melt infiltration

Abstract Laminated boron carbide/titanium carbide (B4C/TiC) ceramic with multilayer structural unit was fabricated by reactive melt infiltration (RMI) process with silicon (Si) and aluminum silicon (Al40Si60) alloy. Laminated B4C/TiC ceramics infiltrated at a low temperature of 1300 °C with Al40Si60 alloy acquired structural unit including two layers of Al3B48C2–SiC, one layer of TiC–Ti3Si(Al)C2, and two layers of in-situ synthesized TiB2 at the interface between Al3B48C2 and TiC layers. The thickness of Al3B48C2–SiC layer, TiB2–SiC layer, and TiC–Ti3Si(Al)C2–SiC layer was found to be about 450, 30, and 90 μm, respectively. Reaction products of Al and B4C consisted of two types of Al–B–C ternary phases including Al3B48C2 and AlB24C4 attributed to the solution of Al in B4C and diffusion of Al into B4C. The diffusion of elements caused by concentration gradient and different diffusion rate of Si led to the formation of TiSi2 layer at 1550 °C and TiB2 layer at 1300 °C between B4C and TiC layers.