The mechanical behaviour of glass and glass-ceramic matrix composites

The mechanical behaviour of several glass and glass-ceramic composites was studied, with particular interest in axial and off-axis properties. The emb rittlement of a cross-ply composite of carbon fibre reinforced borosilicate glass was attributed to the formation of a fibre/matrix interfacial reacti on layer during processing. The tensile properties for cross-ply BMAS (BaO, MgO, Al2O3, SiO2) glass-ceramic composites reinforced with silicon carbide fibres exhibited higher matrix cracking stresses in the 90 and 0 degrees p lies than the carbon fibre reinforced borosilicate glass composite. These w ere attributed to the presence of residual stresses that caused the glass-c eramic matrix in compression. Failure strengths in excess of 300 MPa were f ound for these glass-ceramic composites. Off-axis properties for cross-ply laminates were found to strongly depend on the volume fraction of fibres. C omposites with lower fibre volume fractions exhibited higher interlaminar s trengths than those with higher fibre volume fractions. There also, appeare d to be a link between inhomogeneous microstructures and a larger variation in mechanical properties. (C) 2000 Elsevier Science S.A. All rights reserv ed.