The Research On Control Of Interface Performance And Tribological Properties Of Copper-based Graphite Self-lubricating Composites

Copper-based graphite self-lubricating composites possess wide range of application prospects and values as a manufacture due to its excellent wear resistance,corrosion resistance,and high temperature resistance.However,as the result of the large difference and mismatching of the two-phase atomic bonding type and the thermal expansion coefficient,poor interface reliability of the copper-based graphite composite prepared by the traditional powder metallurgy method was present,which severely restricts its application as the manufacture.This research was based on the design principles of the three-dimensional continuous network structure and probing the influence of structural parameters on the properties,thereby improving the performance and reliability of copper-based graphite self-lubricating composites by the control of interface wetting performance.And the law and mechanism of the influence of the composites were systematically studied.The main research conclusions obtained are as follows:1.The copper-based graphite self-lubricating composite materials with different structural parameters were prepared by powder metallurgy.The influence of particle size of graphite and structure of matrix on the material properties were investigated,and the key controlling factors of the mechanical properties and tribological properties of the materials were determined.The anti-wear mechanism and optimization design criteria of copper-based graphite self-lubricating composites are proposed.2.Based on the design principle of the three-dimensional continuous network structure,the copper alloy three-dimensional continuous network framework effectively maintains the strength and toughness of the matrix.Meanwhile,the weak interface between the graphite particles and the copper alloy matrix induces crack deflection and branching and other dissipation mechanisms to further improve the mechanical properties.The flexural strength,fracture toughness and compressive strength of the homogeneous copper-based graphite composites preparing through optimized the graphite particle size,which were 2.0,4.3 and4.8 times,respectively,higher than that of the copper-graphite composites with unoptimized same graphite content(40 vol%).3.The chromium carbide reaction layer on the surface of graphite particles was prepared by the heat treatment method.The influence of process parameters on the thickness of the interfacial wetting layer and the interfacial bonding properties was investigated.Through the optimization of process parameters,the flexural strength,fracture toughness and compressive strength of the composites with the surface metallization modification of the graphite particles which were 1.5,1.1 and 1.4 times,respectively,of that of the composites without surface modification.