Microstructure And Properties Of ZrB₂ Reinforced Copper Matrix Composites

Copper matrix composites have been widely used in various aspects of industrial production because of their excellent electrical and thermal conductivity,and hardness.However,the particle-reinforced copper matrix composites prepared by the melt reaction method often have agglomeration.In order to prepare composite materials with uniform microstructure,Zr B₂ particles were in-situ synthesized in the Cu melts using Cu-5B master alloy and zirconium sponge particlesas the starting material,and the effects of different preparation conditions on the microstructure and properties of the materials were explored.The materials were analyzed by OM,XRD,SEM,and EDS.The main conclusions are as follows:The distribution of Zr B₂ particles in Cu-Zr B₂ composites prepared by melt reaction method is not uniform,and the aggregate size increases sharply with the increase of particle content.Due to the high activity of Zr,it is prone to ablation when added to the copper melt.The experiment shows that mixing part of the copper powder in the sponge zirconium raw material and adding it into the copper melt can make Zr element fully contact with B element in the copper melt,increase the amount of synthesized Zr B₂,and the hardness of the material has also increased.The results of Cu-2.1Zr-0.5B composites prepared at different temperatures（1150℃,1200℃,1250℃,1300℃）show that:with the increase of preparation temperature,Zr B₂ particles distributed uniformly in the composite form aggregates,the average size of aggregates increase rapidly,and the amount of Zr B₂ particles in the copper matrix decrease.The microstructure and properties of the composites show that with the increase of preparation temperature,the particle size and morphology change significantly and the hardness and conductivity of the composites decrease.In order to further explore the effect of process optimization,the Cu-Zr B₂composites before and after the optimization of preparation conditions are analyzed and characterized.The results show that:by adjusting the reaction raw materials and reaction temperature,it can effectively improve the microstructure uniformity of Zr B₂in composites,increase the synthesis amount of Zr B₂ reaction,and the hardness and conductivity of the material improve significantly.The optimization effect is more obvious when the content of Zr B₂ is high.At the same time,the increased of Zr B₂particle content can also improve the wear resistance of composites.