Current-activated pressure-assisted sintering (CAPAS) and nanoindentation mapping of dual matrix composites

Titanium boride (TiBw) whiskers are currently recognized as one of the most compatible reinforcements for titanium (Ti) that have positively affected its wear resistance and stiffness. The fracture toughness and ductility have, however, been reported to deteriorate at increased TiBw volume fractions, mainly due to the interlocking of these brittle TiB whiskers. This article investigates the processing of dual matrix Ti–TiBw composites, where microstructures are generated consisting of TiBw–Ti composite regions separated by a ductile, predominantly Ti, outer matrix. This microstructural design has the potential to prevent the continuous TiBw interlocking over the scale of the composite (at high TiB w volume fractions), and promote improved toughness of the material. The processing of these unique composites using current-activated pressure-assisted sintering (CAPAS) is discussed in this article. The effect of processing temperature on the microstructure and hardness of Ti–TiBw dual matrix composites is also discussed, together with a simultaneous imaging and modulus-mapping nanoindentation technique used to characterize the composites