Strengthening and toughening of 2D C/SiC z-pinned joint via fiber bridging mechanism

Shear properties of 2D C/SiC z-pinned joint were aimed to improve through z-pin microstructural features optimization. Results demonstrated that joint shear properties could be effectively improved through z-pin density, diameter and ply orientation adjustment. As 2D C/SiC z-pin density increased by approximately 0.1 g/cm³, joint strength increased linearly approximately 18%. As z-pin diameter increased from 3.8 mm to 4.0 mm, joint strength increased approximately 10.1% and 6.9% from 4.0 mm to 4.3 mm. When z-pin ply orientation changed from 0/90 to +45/−45, corresponding joint strength increased approximately 10.9%. Shear rupture of 2D C/SiC z-pin was the only failure mode of corresponding joint, whereas the failure was competing result of shear and bending damages in the z-pin. Corresponding strengthening and toughening mechanisms were related to SiC matrix cracking and carbon fiber bridging.