Tensile strength and fracture toughness of C/C and metal infiltrated composites Si–C/C and Cu–C/C

In this paper, tensile strength and mode I fracture toughness of a low cost carbon–carbon composite (C/C) and liquid metal infiltrated composites Si–C/C and Cu–C/C are investigated based on tensile testing and compact tension testing. Si–C/C and Cu–C/C are manufactured by infiltrating liquid silicon and copper into the low cost C/C, respectively, to make the densification of porous C/C, and to improve the oxidation resistance and the frictional and wearing properties of C/C for various potential applications under high temperature and frictional environments. Experimental results and analysis of microstructures of three composites reveal that the infiltration of liquid metal into C/C significantly influences the tensile strength and fracture toughness of the composite. The tensile strength and fracture toughness of Si–C/C are much lower than original C/C. On the other hand, infiltration of copper into C/C significantly improves the stiffness and strength of Cu–C/C.