Mechanical properties of glass silicate based composites – effects of varying fibre volume fractions

Abstract

The general mechanical characteristics of fibre reinforced ceramic silicate composites were investigated in this paper as a function of the volume fraction of reinforcing fibres. It is found that the fibre volume fraction, the fibre/matrix interfacial properties and the microstructures of the composites are all important in determining the strength of the material and their fracture mechanism. This investigation revealed the existence of microcracks and interfacial debonding caused by stress concentration and differential contraction between fibre and matrix during the moulding process, which in turn affected the mechanical properties. This evaluation used chopped fibres (alkali resistant glass fibre) as the reinforcement with fibre volume fraction varied under optimised moulding conditions (temperature and pressure). In addition, a selected matrix formulation was used for the analysis of the microstructural behaviour of the moulded composite while its fracture surface was analysed. The results showed that the composite stress–strain behaviour and the residual stresses associated with moulding could be controlled by the moulding process and volume fractions. This is supported by the results of residual stress simulation and analysis between the fibre/matrix interfaces.

Keywords:

• Silicates
• Ceramics
• Composites
• Glass fibre
• Moulding temperature