Diffusion bonding and interfacial microstructure analysis of AlMgB14-TiB2 to Nb

Simultaneous synthesis, consolidation and bonding of AlMgB14-TiB2 to Nb were achieved by field activated and pressure assisted synthesis (FAPAS). The samples produced by FAPAS were characterized for microstructure and hardness. Observation via the scanning electron microscopy (SEM) showed that TiB2 particles distributed in the AlMgB14 matrix uniformly, with some MgAl2O4 impurities formed along the TiB2 boundary. A micro-hardness of 3780HV1.0 for AlMgB14 reinforced with 30 wt% TiB2 was achieved. Cross section investigation showed a transition region about 180 μm wide between the Nb substrate and the sintered AlMgB14-TiB2 that could be divided into two parts: one part was formed through B diffusion into the Nb substrate; another part was mainly composed of TiB2 particles. Due to the small atomic diameter, the diffusion of boron into the Nb substrate was substantial which led to a successful bonding process.