Fabrication And Stiffness Prediction Of Hybrid Carbon And Silicon Carbide Fiber-reinforced Silicon Carbide Matrix Composites

Continuous fiber reinforced SiC matrix composites exhibit excellent properties such as high specific strength,high specific modulus,low density,high temperature resistance,oxidation resistance.Currently,its widely used in aerospace craft,automobile,nuclear system and so on.Hybrid fiber composite material not only retains the advantages of single fiber reinforced composite but also exhibits high mechanical wear and thermal properties.However,it is scare to find any reports about this field.In this research,the two dimensional carbon fiber and silicon carbide fiber reinforced SiC matrix composite was fabricated and the stiffness of this kind of composite was calculated by using the finite unit analysis The room temperature flexural strength and tensile strength were measured.A novel method was used to prepare the Si C matrix and the properties of this as-prepared SiC matrix was measured.Finally,the predicted results were compared with the experimental results.As for the fabrication of SiC matrix,SiC foam was prepared by using the protein foaming method.Then,the SiC foam was densified by using the PIP route with using LPVCS as the precursor.The density,porosity,pore size distribution and some engineering constants,such as the Young’s modulus,the shear modulus and the poisson ratio,of the SiC matrix were measured.The configuration of the two dimensional hybrid composite was designed.A reasonable unit cell model of the two dimensional hybrid composite was promoted.The space shape of the fiber in the unit cell model was analysized.With the consideration of the influence of the interfacial coating on the mechanical property of the composite,the stiffness of the composite were analysized by using the average stiffness method.It was found that the experimental results fit well with the predicted results when the ratio of carbon fiber layer and silicon carbide fiber layer was 1:5.At this ratio,the flexural strength and tensile strength of this two dimensional hybrid composite was 572.1MPa and 111.1MPa,respectively,which is much higher than those of the SiC/SiC composite(flexural strength was 512.6MPa,tensile strength was 102.9MPa),indicating that the addition of carbon fiber was benefit for the mechanical properties of the composite.The load-displacement curves of the two dimensional hybrid composite exhibit quasi-ductile behavior.