Research On Preparation,microstructure And Properties Of ZrC/ZrB₂ Reinforced Cu-matrix Composites

Because of its good conductivity,thermal conductivity and high strength,Cu-matrix composites are widely used in electronic communication conductive materials,electrode contact contacts,aerospace and other aspects.In this kind of composites,ceramic particles with high strength,high modulus and good thermal stability are usually used as reinforcements to strengthen the materials through various processes to obtain composites that meet the needed requirements.In this paper,Zr C and Zr B₂ particles were selected as reinforcements to prepare Zr C/Zr B₂reinforced Cu-matrix composites by the way of synthesizing Zr C and Zr B₂ in-situ reaction in the melt,and their structures and properties were studied.The research on Zr C particle reinforced Cu-matrix composite shows that using graphite as carbon source,the mixture of zirconium and graphite can be effectively introduced into copper melt and Zr C can be synthesized by wetting with Zr-C reaction.However,the method requires sufficient contact between zirconium and graphite to enter the graphite,and the graphite that does not contact with zirconium will be burned,which limits the absorption rate of graphite.It is an e ffective method to increase the Zr/C ratio of mixed raw materials.With the same amount of graphite,more Zr C can be synthesized by increasing Zr/C ratio,and the size and distribution uniformity of Zr C are improved obviously.The research on Zr B₂ particle reinforced Cu-matrix composite shows that using Cu-B master alloy as boron source,Zr B₂particle reinforced Cu-matrix composite can be prepared by melt in-situ reaction method combined with traditional casting process,and the composite shows high hardness,good wear resistance and high conductivity at the same time.But the structure of the synthesized Zr B ₂particles is not uniform,and its particle size range is wide and tends to aggregate.In the process of synthesizing Zr B₂,the existence of Al element in copper melt can effectively improve the homogeneity of Zr B₂.By adding Al,the size of Zr B₂ can be reduced,and the morphology of Zr B₂ can also be changed from flake to polyhedral or spherical,and the distribution of Zr B₂ particles in the composite can be more uniform.The results show that the effect of Al on Zr B₂ is related to its selective adsorption on the surface of Zr B₂.In the process of synthesis and growth of Zr B ₂,Al is easy to adsorb on its surface,thus inhibiting its growth.