挤压态CNTs/Al-Zn-Mg-Cu复合材料摩擦磨损性能的研究

Study on Friction and Wear Properties of As-extruded CNTs/Al-Zn-Mg-Cu Composites

通过熔融铸造工艺制备了12vol%CNTs(碳纳米管)/Al-Zn-Mg-Cu铝基复合材料,随后对复合材料进行了热挤压变形处理。利用MG-200型销盘式摩擦磨损试验机对铸态及挤压态复合材料进行摩擦磨损测试,研究了不同载荷作用下挤压态复合材料的磨损性能演变,并且探究了挤压态材料的微观组织和力学性能。结果表明:CNTs的加入细化了Al-Zn-Mg-Cu合金中的α-Al晶粒并且提高了合金的力学性能。随后对复合材料进行了热挤压变形,材料的晶粒被挤碎,CNTs与第二相沿挤压方向呈流线型分布。随着外加载荷的增加,挤压态复合材料的磨损率逐渐增大,磨损形貌逐渐恶化。在40 N载荷作用时,挤压态复合材料的磨损率为0.011976 g/mm,与铸态复合材料相比磨损率降低了80.11%,此时挤压态材料的磨损机制主要是磨粒磨损和氧化磨损。

12vol%CNTs(carbon nanotubes)/Al-Zn-Mg-Cu aluminum matrix composites were prepared by melt casting process,and then the composites were deformed by hot extrusion.Friction and wear tests of as-cast and as-extruded composites were carried out by MG-200 pin-disc friction and wear testing machine.The evolution of wear properties of as-extruded composites under different loads was studied,and the microstructure and mechanical properties of as-extruded composites were investigated.The results show that the addition of CNTs refines theα-Al grains and improves the mechanical properties of the alloy.Subsequently,the composite is subjected to hot extrusion deformation,the crystal grains of the material are crushes,and the CNTs and the second phase are streamlined along the extrusion direction.As the applied load increased,the wear rate of the as-extruded composite gradually increases,and the wear morphology gradually deteriorate.Under the load of 40 N,the wear rate of the as-extruded composite is 0.011976 g/mm,which is 80.11%lower than that of the as-cast composite.At this time,the wear mechanism of the as-extruded material is mainly abrasive wear and oxidative wear.