Deformation and Fracture Behaviour of Composites with Brittle Zones on Fibre Surfaces

Abstract

Effects of the brittle zones with multiple crackings on deformation and fracture behaviour of ductile fibre-composites were investigated by using composites consisting of two components of aluminium-alumina as well as three components of stainless steel-brittle zone-aluminium. The strength of the fibres was raised as long as the brittle zone with multiple crackings adhered to the fibres and was not fractured in the transverse direction by the compressive stress, as ascertained in our previous work. The effects of grain size of ductile aluminium fibre on deformation behaviour of the binary aluminium-alumina composite were discussed by using the strengthening mechanism of the brittle zone previously proposed by us. The strengthening effect of the brittle zone on the ternary composite arose only from the mechanical interaction between the brittle zone and the fibre. The mechanical interaction between the brittle zone and the matrix was negligible since the interfacial bond between them was very weak. The brittle zone in itself did not affect fracture behaviour due to spalling or fracture by the compressive transverse stress prior to composites fracture. The weak bond between the brittle zone and the matrix caused bridging or splitting.