Fabrication And Wear Behavior Of TiC_x Nanoparticle Reinforced Copper Matrix Composites

Copper is widely used in automotive, electronics, electrical, mechanical manufacturingand other fields because of its high electrical and thermal conductivities, good corrosionresistance and ease of fabrication. However, due to low hardness, low tensile yield strengthand poor wear resistance of copper, etc., limited its widespread application. In recent years,it is more appropriate to incorporate dispersoid ceramic particles such as oxides, carbides,borides with high melting point, high hardness, superior wear resistance and thermalstability into copper, leading to the formation of with good electrical conductivity, thermalconductivity, and excellent resistance and wear resistance. However, because of poorwetting between molten copper and most ceramics particles, the success of introductionceramic particles into Cu matrix become an important factor to resolve Cu matrixcomposites widely production and application.In this paper, Cu-Ti-C system was selected as the research objectives. The in situsynthesis of nanoTiCx-Cu master alloys with high hardness and well abrasion resistancesuccessfully prepared by using the method of TE+HP. It was studied the Cu content,reactant C/Ti molar ratio and carbon source have important effects on the growthmorphology and size of the TiCxparticles formed in the Cu-Ti-C system. The growthmechanism and morphology evolution of TiCxwith different Cu contents was studied. Themicrostructure morphology of TiCxreinforced Cu-Cr-Zr composites prepared by the methodof stir casting using TiCx-Cu intermediate alloy was investigated. It revealed the effects andmechanism of the TiCxcontents on the abrasive wear properties, the electricalconductivity(%IACS) and thermal conductivity(W·m-1·K-1) of the Cu-TiCxmaster alloysand TiCxreinforced Cu-Cr-Zr composites. The main work of this paper is given as follows: 1) In Cu-Ti-C system, found that Cu content and the size of different carbon sources havesignificant impact on the size and morphology of TiCxsynthesized by TE+HP: Asrevealed TiCxmorphology gradual transformation to nearly spherical from cubic (cubeâ†'truncated octahedralâ†'close to sphereâ†'sphere) and the size progressively largerwith the contents of Cu decrease; With the decrease of size of carbon source, the size ofTiCxis reduced, morphology of TiCxgradually close to sphere and sphere by the cube;Reveals the rule of different carbon sources on the TiCxparticle surface morphology,compared to carbon nanotubes and carbon black, the pretreatment carbon nanotubessmaller in size and more active, TiCxparticles synthesized by TE+HP are smaller.2) Reveals the different molar ratio of C/Ti on the TiCxmorphology pattern preparedthrough TE+HP: As the Cu content is70vol%, molar ratio of C/Ti≤0.6, TiCxparticles grow as octahedron; molar ratio of C/Ti≥1.2, TiCxparticles grow as cubic;however molar ratio of C/Ti is0.8and1.0, TiCxparticles grow as truncated octahedral,close to sphere and sphere.3) TiCx/Cu-Cr-Zr composites were successfully prepared by adding TiCx-Cu intermediatealloy into Cu-Cr-Zr melt, the grains of8vol.%TiCx/Cu-Cr-Zr composite grains has beensignificantly refined compared to remelting Cu-Cr-Zr alloy, the hardness of increasedfrom97.1HV to118.5HV, Brinell hardness from the75.1HB raised to86.8HB.4) The volume losses of the composites TiCx/Cu are reduced with the increase of TiCxceramic content increases. the continuously rubbing between SiC and the TiCxparticlesof matrix surface, SiC weaken the effectiveness of surface passivation abrasive cutting,thereby reduced the wear volume loss of the composites. At the same time compared toCu-Cr-Zr alloy the wear resistance of the8vol.%TiCx/Cu-Cr-Zr composite increased14.2%.5) The contents of TiCxceramic particles increases leads to the conductivity of thecomposite material decreases for the free electrons movement blocked. The electricalconductivity of8vol%TiCx/Cu-Cr-Zr composites was reduced from64.71%IACS to52.93%IACS compared to Cu-Cr-Zr alloy, it is also a point to note that the the thermalconductivity reduced by202W·m-1·K-1to179W·m-1·K-1in25℃.