| Due to its high thermal conductivity,electrical conductivity and strength,CuCrZr alloy has been widely used in the fields of resistance welding electrodes and integrated circuit lead frame materials.However,its low wear resistance and ablative resistance seriously restrict the application in sliding guide materials.The purpose of this study is to improve the conductivity and strength of Cu-0.7Cr-0.12Zr alloy by adding Ag and Nb elements step by step.Then the graphite,W and SiC micro/nano functional phase particles were compounded with the copper alloy with high conductivity and high strength to obtain the copper matrix composites with high conductivity,high strength,high wear resistance and low ablation.The results show that:（1）After solid solution aging treatment,the conductivity and hardness of Cu-0.7Cr-0.12Zr-xAg（x=0,0.1,0.2,0.3）and Cu-0.7Cr-0.12Zr-0.1Ag-xNb（x=0.06,0.12,0.18）alloys were significantly improved.Under the heat treatment process of 960 ℃×120 min+500℃ ×120 min,the conductivity and hardness of Cu-0.7Cr-0.12Zr-0.lAg alloy reached the highest,which were 86.17%IACS and 97.4 HB,respectively.Cu-0.7Cr-0.12Zr-0.1Ag-0.12Nb alloy conductivity and hardness reached the highest,respectively 92.7%IACS and 98.2 HB.（2）The samples microstructure analysis of Cu-0.7Cr-0.12Zr-0.1Ag-0.12Nb-xgraphite（x=0,0.25,0.5,0.75）,Cu-0.7Cr-0.12Zr-0.1Ag-0.12Nb-xSiC（x=0,0.5,1,1.5）and Cu-0.7Cr-0.12Zr-0.1Ag-0.12Nb-xW（x=0,2,4,6）prepared by combining powder metallurgy with casting shows that:the graphite,W and SiC functional phase particles were evenly distributed in the copper matrix composite samples,and the microstructure of the samples are free of defects.The addition of graphite significantly reduces the friction coefficient and improves the lubricity of copper matrix composites.The friction coefficient of Cu-0.7Cr-0.12Zr-0.1Ag-0.12Nb-0.5graphite composite material is the lowest value of 0.49 under the condition of 20 N load and 0.8 m/s friction speed.The addition of W in Cu-0.7Cr-0.12Zr-0.1Ag-0.12Nb-W composites significantly improved the ablative resistance of the composites.When the arc ablation times were all 150 times,the arc ablation amounts of the Cu-0.7Cr-0.12Zr-0.1Ag-0.12Nb-6W composites at electric currents of 25A and 100A were 20.5 u g/C and 56.26 μ g/C respectively,which indicated that the W particle reinforced copper matrix composites had better ablative resistance at low electric currents.The addition of SiC improves the wear resistance of copper matrix composites,which makes the composite have a smaller wear rate.Under the condition of load 20 N and frictional velocity 0.8 m/s,wear rate of Cu-0.7Cr-0.12Zr-0.1Ag-0.12Nb-lSiC composites is at least 0.97×10-5 cm3·N-1·m-1.（3）The tensile strength and hardness of Cu-0.7Cr-0.12Zr-0.1Ag-0.12Nb-0.5graphite-2W-1SiC composites were significantly enhanced after deformation strengthening.When the deformation rate is 80%,the tensile strength and hardness are 603 MPa and 110.96 HB,respectively.The highest conductivity of the composites without deformation is 76.9%IACS.Under the conditions of load 20 N and friction velocity 0.8 m/s,the friction coefficient and wear rate of the composite samples are 0.25 and 3.83×10-5 cm3·N-1·m-1 respectively.The ablative resistance is good at current 25 A,and the arc ablative amount for 30 times is 24.56 u g/C. |
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