Fibre debonding and breakage in a whisker-reinforced metal

A numerical cell-model analysis of the development of damage in aluminium reinforced by aligned, short SiC fibres, is given for materials with arrays of transversely aligned fibres, to be compared with the results obtained previously for transversely staggered fibres. The stress distributions in the matrix and fibres are quite different for the different fibre arrangements, and this has a significant effect on failure by fibre breakage or decohesion. Fibre fracture is represented by a critical value of the average tensile stress on a cross-section, while interfacial failure is modelled in terms of a cohesive zone formulation that accounts for decohesion by normal separation as well as by tangential separation. It is shown that highly constrained plastic flow associated with transversely aligned fibres gives rise to early transverse void growth towards coalescence, but the onset of failure requires higher stress levels.