Forming of Long Fibre and Particulate Metal Matrix Composite Components
In this paper the evolution of damage and residual stress during the forming of metal matrix composites is considered. The incorporation of a second phase makes the introduction of damage more likely than when forming monolithic materials. Furthermore, internal stresses can develop during forming, either from plastic deformation, or because of the thermal expansion mismatch between the phases. The evolution of stress and damage during forming are illustrated with reference to the forging of a brake disc component made from Al-SiC particulate and the machining of a hoop wound structure made from Ti reinforced with continuous SiC fibres. Unsurprisingly, the reinforcement geometries impose very different constraints on the available process routes and lead to quite different concerns in the final finished products. In the former case, the concern is to refine the process to minimise the introduction of damage, while in the latter an understanding of the evolution of thermal misfit stresses is important especially with respect to non-conformance distortion and life prediction.
Philippe J. WITHERS
forging, damage evolution, neural networks, machining, thermal residual stresses.