Mechanical behaviour of an Al-matrix composite reinforced with nanocrystalline Al-coated B4C particulates

In metal - matrix composites (MMCs), interfacial bonding between the metal matrix and the ceramic reinforcement plays a crucial role in their mechanical performance. In the present study, B4C particles were cryomilled with an Al alloy to produce a composite powder, in which the B4C was uniformly distributed in nanocrystalline Al. The cryomilling developed a strong bond between the B4C and the Al, allowing the nanocrystalline Al to act as a coating with a strong ceramic - metal interface. This cryomilled composite powder was then introduced, as a reinforcement, into a conventional Al alloy to strengthen the material. After consolidation, the result was a bulk Al - matrix composite reinforced with B4C particles encapsulated in nanocrystalline Al. This composite exhibits greatly improved strength and stiffness.