Fracture Toughness and Work of Fracture of SiC-Fibre Reinforced Glass Matrix Composite

The applicability of the chevron-notch technique for changes monitoring in fracture behaviour of fibre/glass matrix composites has been investigated. A commercial SiC-fibre reinforced glass matrix composite was aged in argon at temperatures in the range 500–700 °C for duration of up to 1000 hrs. The mechanical properties of aged samples were evaluated at room temperature by using four-point flexure strength and three-point flexure chevron notch techniques. For identification of the unstable fracture onset an acoustic emission technique was applied. The fracture toughness values in the range 19–26 MPam1/2 were little affected by the ageing conditions except for the most severe ageing conditions. The procedure for the work of fracture determination and its dependence on ageing condition is presented.