Fabrication, microstructure and mechanical properties of co-continuous TiCx/Cu-Cu4Ti composites prepared by pressureless-infiltration method

The co-continuous TiCx/Cu-Cu4Ti composites were prepared by infiltrating melting Cu into TiC0.5 porous preforms. TiC0.5 porous preforms were firstly synthesized by in-situ solid reaction process using powder Ti and carbon black as the starting materials, PVB as shaping and pore-forming agent. The prepared TiC0.5 preforms showed 3D-connected visible pores characterized with two classes of sizes, i.e. intergranular pores with size of 10-30 mu m and intracrystalline pores with 2-3 mu m. Microstructure and phase compositions of the composites were detected by scanning electron microscopy (SEM) equipped with EDS and X-ray diffraction (XRD). Metal region of the composites contained Cu as well as a new phase Cu4Ti, which was formed by reaction of Cu and TiC0.5. Composites prepared by this method had a compact structure and strong interface. Meanwhile, metal phase and ceramic phase maintained a co-continuous structure in three dimensions. Cu-Cu4Ti entered into the TiCx ceramic particles like root structure during the infiltration process. Flexural strength, fracture toughness and Vickers hardness of the composites reached 948.20 +/- 124.04 MPa, 12.62 +/- 0.37 MN m(-3/2) and 606.4 +/- 36.7 respectively when content of TiCx was 71.22 vol%.