Strength distribution of Ti/SiC metal-matrix composites under monotonic loading

摘要

The strength of metal matrix composites shows wide scatter on account of variability in the strengths of individual fibres. The relationship between the strength distribution of the fibres, and that of the composite is also affected by the non-linear matrix and fibre/matrix interfacial responses. The present study aims to describe the strength distribution of 2D and 3D commercial Ti/SiC composites. This is accomplished by performing Monte Carlo failure simulations of these composites, comprised of up to 128 fibres. A detailed deformation theory based model, developed and validated against experimental data in previous work, is used to calculate load redistribution in the course of each simulation. The empirical composite strength distribution obtained from the simulations follows weakest-link scaling. A stochastic model for the clustered propagation of fibre breaks, akin to a model proposed for polymer matrix composites in the literature, captures the empirical weakest-link strength distribution. A scaling relationship is derived between the composite strength and composite size for a number of reliability levels.