The Research Of Microstructure And Mechanical Properties On Cu/WC Functionally Graded Materials

Cu/WC composite material is one of the most studied materials in reinforced metallic matrix composite materials. Cu has good electrical conductivity, thermal conductivity and corrosion resistance, but it has low strength; WC has high hardness, strength and good wear resistance, thermal stability, adding second-phase WC reinforcement in the Cu-based material can combine the advantages of both materials, it is mainly used for resistance welding electrodes and high current sliding contact as wear-resistant materials.However, when such a homogeneous composite material is in use, especially in high-temperature environments, the problem of thermal stress relaxation has no good solution, thus affecting the heat-resistance, durability,cyclic resistance and service life of materials.The concept of functionally graded materials (FGMs) is based on the question of the thermal stress relaxation, compared with traditional homogeneous composite materials, the difference is that its organization and structure in the thickness direction has a clear gradient variation.This article starts with the research status and trend of development of FGM, three-laminated structure of Cu/WC FGM is prepared by powder metallurgy solid-state sintering method, the effect of its preparation under different process conditions and microstructure changes on its macroscopic mechanical properties are specially studied, thermal stress distribution of FGM under the action of temperature load, mechanical load and thermal-mechanical coupling load are discussed respectively, and are compared with Cu/WC Bi-material in detail.The buried powder sintering technology is applied in the material sintering process, three-layer Cu/WC FGM is obtained with denser microstructure, this method has advantages of simple equipment and low-cost.The effect of the process conditions on its microstructure is confirmed through the Cu/WC FGM secondary processing, combined with experimental test, the relationship between the microstructure changes and its macroscopic mechanical properties is analyzed emphatically. By using sequential coupling method, ANSYS finite element simulation on FGM and Bi-material is carried out, their differences in stress distribution and changes under the action of thermal-mechanical coupling load are discussed.Through the study of this paper, following technologies for preparation and performance testing of FGM can be useful:(1) Buried powder sintering technology for preparation of metal/ceramic FGM class is feasible;(2) Secondary processing techniques can significantly improve the macroscopic mechanical properties of FGM, it can be used in the preparation process of FGM;(3) The use of sequential coupling method in ANSYS finite element simulation on FGM.