In situ investigation of fracture behavior in monocrystalline WCp-reinforced Ti-6Al-4V metal matrix composites produced by laser melt injection

In situ tensile testing in a scanning electron microscope was performed to investigate the fracture behaviour of metal matrix composites reinforced with monocrystalline WC particles. The fracture properties are clearly enhanced when monocrystalline WC particles are used as reinforcement. Two crack nucleation mechanisms can be distinguished: the WC particle cracking and decohesion of the WC/W2C interface. The weakest microstructure in the particle/matrix reaction zone is the WC/W2C interface rather than the expected TiC layer. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.