Fabrication And Tribological Properties Of Ti₃AlC₂/Cu Co-Continuous Composites

The ternary compound Ti3AlC2 has an excellent comprehensive property of metals and ceramics, It is expected to obtained an excellent properties, if compound it with Cu in some way. This paper analyzes the technology of fabricating co-continuous structure Ti3AlC2/Cu matrix composites based on Ti3AlC2 through pressureless infiltration of porous ceramics as precursor. By X-ray diffraction (XRD), scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS) observation, the sintering parameters of the high purity Ti3AlC2, the phase and the microstructure changes of Ti3AlC2/Cu co-continuous composites via different sintering processes were explored, and some of its properties were characterized.The results showed that:(1) A high purity Ti3AlC2 precast body was fabricated by sintering the mixture of Ti, TiC, Al and Sn powder at 1380℃ and 1450℃ for 10 min. The open porosity is respectively 54%±3.2% and 42%±2.1%.(2) Using the method of pressureless infiltration to impregnate the Ti3AlC2 porous preform with Cu at 1170 "C in different holding times and the Ti3AlC2/Cu co-continuous composites with high density were prepared. During the course of the pressureless infiltration, Cu and Ti3 AIC2 will occur partial reaction at a high temperature, Ti3AlC2 particles break up into TiCx particles, and Al is formed into the matrix of Cu, which will form into Cu (Al) solid solution. Ceramic matrix and metal skeleton intertwined in the composites, they present a three-dimensional continuous distribution network respectively with a strong interface combination.(3) The Ti3AlC2/Cu co-continuous composites has good mechanical properties. The average compressive fracture strength of 46Ti3AIC2/CU co-continuous composites sample with a holding time of 2.5h reaches 1033MPa and the average fracture strain still keep 25.3%;the bending strength reaches 810.48MPa and the fracture toughness Kic is 15.02 MPa·m1/2.(4) The holding time and the open porosity of precast body have significant effect on the composites. The melted liquid of Cu cannot be fully immersed in the pore of the Ti3AlC2 precursor when the holding time is too short. When the holding time is prolonged, the density and the comprehensive performance improved. As the porosity increases, the composites showed outstanding metallic properties. The composites can show notable ceramic properties when the porosity decreased.(5) The Ti3AlC2/Cu co-continuous composites has excellent friction and wear properties. Especially in high sliding speed of 30 m/s, its friction coefficient is 0.35, and the wear rate is less than 2.5×10-6mm3/N·m.