Tensile and compression properties of CMC laminates reinforced with Z direction pins

A preform consisting of plain woven fabric and Z-pins through thickness reinforcements was prepared. The process of chemical vapor infiltration was used to fabricate the ceramic matrix composite laminates reinforced with Z-pins. Using uniaxial tensile tests and compression tests, tensile and compression mechanical properties were investigated, and fractographies were used to analyze the fracture mechanism. The results show that the damage of plain-weave ceramic matrix composite with Z-pins reinforcement is propagated at lower tensile stress, and that the tensile stress-strain curve for this laminates is nonlinear. The damage of the fibre in-plain during pins insertion and stress concentration near pins become the reasons of fracture near Z-pins. The tensile fracture mechanisms of plain-weave ceramic matrix composite with Z-pins reinforcement are matrix crack and the fibre in-plain pulling out. The compressive stress-strain curve for plain-weave ceramic matrix composite with Z-pins reinforcement laminates is also nonlinear. Compression fracture is an inclining section, which inclination angle equals to waviness of the fibre in plain woven fabric. The compression fracture mechanism of plain-weave ceramic matrix composite with Z-pins reinforcement is delamination crack, matrix crack in transverse yam and shear fracture of Z-pins.