A study on fibre reinforced 7740 glass composite and its interface bonding strength

Graphite yarn or Nicalon Sic yarn reinforced 7740 borosilicate composites were produced by hot–pressing the lay–up infiltrated unitapes at the temperature of 1200°C under the pressure of 6.7 MPa for 1 hr. in the atmosphere of nitrogen. The flexure strength (σ2) and the impact toughness (ακ) of C/7740 composite reached respectively to 792 MPa and 31 KJm−2. The σ2 and fracture toughness (Klc) for SiC/7740 composite were 780 MPa and 16.3 MPa m−1/2 respectively. It was discovered that σ2, κ and Klc all had a maximum value with the volume fraction of fibre (Vf) increasing. The best value of Vf was about 40–45%. It was proved that σ2 was fit well in to the Weibull Distribution as well as the Normal Distribution The interface bonding strength (τ) of SiC/7740 composite was measured successfully by Marshall Indentation Method. The effect of heat–exposing time (t) of fibre in air at 600°C on T and the relationship between τ and Klc were also dealed with. It was also discovered that T increased, but Klc decreased with τ prolonging in the range of present experiment. The mechanism of hot–pressing densification and other problems were also touched with.