Mechanical properties and fracture behaviors of C/C composites with PyC/TaC/PyC, PyC/SiC/TaC/PyC multi-interlayers

摘要

Carbon/carbon (C/C) composites with PyC/TaC/PyC or PyC/SiC/TaC/PyC multi-interlayers were prepare by isothermal chemical vapor infiltration, followed by Furan resin impregnation and carbonizatio Microstructures, mechanical properties including flexural strength, ductile displacement, and fractal behaviors of composites were studied. Furthermore, composites were heat treated at 2000 deg C to stud the effects of heat treatment on mechanical properties and fracture behaviors. PyC/TaC/PyC and PyC/Sil TaC/PyC multi-interlayers have been deposited uniformly in C/C composites. With the iatroduction PyC/TaC/PyC multi-interlayers in C/C composites, the flexural strength decreases; however, the ducti displacement increases. The fracture behavior changes from brittleness (0 percent TaC) to pseudo-ductili (5 percent TaC) and high toughness (10 percent TaC). When PyC/SiC/TaC/PyC multi-interlayers are introduced in C composites, the flexural strength is improved remarkably from 270 MPa to 522 MPa, but the ducti displacement decreases obviously from 0.49 mm to 0.24 mm, and the fracture behavior becomes britt again. After heat treatment at 2000 deg C, the flexural strength decreases, but the ductile displaceme increases and pseudo-ductility or high toughness can be obtained.