Theoretical model for solid-state consolidation of long-fibre reinforced metal-matrix composites

A quantitative theoretical model has been established for the solid-state consolidation process of long-fiber reinforced metal-matrix composites, involving the bonding of aligned fiber mats and matrix foils. The analysis is based on a rectangular fiber array and takes into account the plastic flow and power-law creep of the matrix, which are taken as the dominant mechanisms of consolidation. Theoretical predictions are examined and compared with experiments on the consolidation of monofilament SiC fibers and a Ti-6Al-4V matrix. These generally show a good agreement, particularly for the samples with relatively closely spaced fibers processed using comparatively high pressures. The model overestimates the bonding time to some extent when wide fiber spacing and low pressures are involved, due to non-rectangular fiber arrangements encountered in the present experiments and the possible effect of diffusion that is not considered in the creep-based analysis. Contact pressures at fiber/matrix interfaces at the initial stages of consolidation are also quantitatively determined and can be used to tailor the process for minimum fiber damage