Influences of Distribution of Fiber Strength and Residual Stresses on Tensile Strength of SiC Fiber-reinforced TiAl Matrix Composites

Tensile behavior of SiC/TiAl composite was investigated. Main results are:(1) The interface of the composite was weak. The fracture of the composite was accompanied by the fracture of matrix, fracture and pull-out of fibers, and interfacial debonding along the whole length between grips.(2) Under the condition that strength of individual fiber is determined by the largest defect, the extreme value distribution function was applied for description of the distribution of the size of the maximum defect of fibers, and the strength of the composite at room temperature based on the fiber bundle strength was calculated. The experimentally measured strength could be accounted for by this calcuation.(3) From the results of a Monte Carlo simulation, it was suggested that the improvement of frature strain of the matrix and minimization of the residual stresses are needed to achieve high strength.