Influence of brick pattern interface structure on mechanical properties of continuous carbon fiber reinforced lithium aluminosilicate glass-ceramics matrix composites

Continuous carbon fiber reinforced lithium aluminosilicate glass-ceramic matrix composites have been fabricated by sol-gel process and hot pressing technique. The results show that the Cf/beta-eucryptite composites hot pressed at 1300 degrees C and Cf/beta-spodumene composites hot pressed at 1400 degrees C form weak interface with brick pattern characteristics, leading to high mechanical performance. The maximum flexural strength and fracture toughness reach 571 +/- 32 MPa and 9.8 +/- 0.6 MPa m(1/2) for Cf/beta-eucryptite composites and 640 +/- 72 MPa and 19.9 +/- 1.8 MPa m(1/2) for Cf/beta-spodumene composites. On increasing the hot pressing temperature, the active chemical diffusion consumes brick pattern interface layer, which leads to the formation of strong bonding between carbon fiber and the matrix. As a result, the composites exhibit brittle fracture behavior and the mechanical properties decrease significantly. (C) 2011 Elsevier Ltd. All rights reserved.