The possibility of using fibres of varying thermal expansivities to reduce stresses generated from thermal gradients in service has been explored. Laminates of aluminosilicate and alumia-matrix composites were fabricated using a combination of Nextel 610 and Nextel 720 fibres. The composites were tested for mechanical behaviour and thermomechanical behaviour in comparison to control composite specimens which contained a single type of fibre. Mixed-fibre composites show strength and fracture behaviour similar to those of single fibre-type composites. Their thermomechanical behaviour is consistent with 2D laminate models, making it possible to design composites using such models. Inter laminar shear stress is a key, but sole limitation and the use of gradation in fibre mixture is suggested.
