The influence of internal stresses on the mechanical behaviour of glass-ceramic composites

Abstract

Discontinuous, randomly oriented nickel fibre/glass-ceramic composites have been prepared by a hot-pressing technique and the effect of expansion mismatch on the resultant mechanical properties has been investigated. Composite strength is reduced by fibre additions, the effect being greatest at low volume fractions of fibre. However, in contrast to the unreinforced materials which are extremely notch-sensitive, the strength of the composites is not adversely affected by the presence of a notch. Work of fracture is significantly increased but the effect is greatest for matched-expansion materials. A 40 vol % matched-expansion composite exhibits a value for work of fracture of 15.7±0.5 J m⁻²×10³, and a flexural strength of 182±8 MN m⁻², and is tougher and stronger than similar systems reported in the literature.