Superior mechanical properties of lithium aluminosilicate composites by pyrolytic carbon intercalated carbon fibers/carbon nanotubes multi-scale reinforcements

Abstract

Performance degradation always occurs in carbon fibers/carbon nanotubes (CFs/CNTs) multi-scale reinforced composites prepared by chemical vapor deposition (CVD) method. In this study, pyrolytic carbon (PyC) interlayers are introduced to overcome this problem, and the mechanism is studied in detail. The multi-scale reinforcements are combined with lithium aluminosilicate (LAS) glass-ceramic into ceramic matrix composites by slurry impregnation and hot pressing sintering. The results show that the PyC interlayers can protect the CFs from corrosion of the catalyst at high temperature, improve stress transfers and promote the synergy between various components. The CNTs and LAS matrix form a transition area, which causes deflection and shunting when cracks propagate. These factors have greatly increased the crack extension energy, so the mechanical properties have been greatly improved. The flexural strength, fracture toughness and work of fracture reach 602 ± 55 MPa, 10.7 ± 2 MPa m1/2, 4.6 ± 0.7 kJ m−2, respectively, which are 42.3%, 42.6% and 76.9% higher than CF/LAS. This work expands the study of the CFs/CNTs multi-scale reinforcements and the LAS composites, and provides a useful reference for the related research.