Interface effects during consolidation in titanium alloy components locally reinforced with matrix-coated fibre composite Original Research Article

An investigation has been made of diffusion bonding at the interface between a local reinforcing metal matrix composite and a monolithic engineering material. Diffusion bonding occurs during the consolidation of the composite during component manufacture. In this study, the composite is made up from Ti–6Al–4V titanium alloy coated SiC fibres, and the monolithic engineering material is also Ti–6Al–4V, but with a different microstructure. An interface model is presented which takes account of diffusion bonding and which is able to describe the deformation behaviour at the interface between composite and monolithic material during composite consolidation. The model is developed from an existing diffusion bonding theory, and is implemented into finite element software. The finite element simulations, and results of experiments, show that diffusion bonding can lead to localised deformation, the inhibition of consolidation, and a resulting inhomogeneous distribution of consolidated and unconsolidated regions during component manufacture. A further effect of the diffusion bonding is to increase the level of component distortion which results from the constraint imposed on the consolidating composite. The interface model presented enables the simulation of practical forming processes so that process variables such as temperature and pressure can be chosen to ensure appropriate finished component properties.