氮化硼纳米片增强铜基复合材料的界面调控与性能

Interface regulation and properties of boron nitride nanosheets reinforced copper matrix composites

铜因其高导电和高延性的优点在电刷及电触头材料有着广泛的应用前景。随着电力输送行业的快速发展,铜本身低强度的劣势已无法满足需求,亟需开发一种高强高韧的铜基复合材料(CMCs)来弥补铜材料的缺陷。氮化硼纳米片(BNNSs)因其优异的力学及高温结构稳定性能,有望作为铜基复合材料良好增强体,为我国航空航天及交通运输等产业开发出极具战略意义的复合材料。本文采用粉末冶金工艺制备了具有高综合性能的BNNSs增强铜基复合材料(BNNSs/Cu)。研究了不同热处理条件下复合材料微观组织及界面演变特征,测试复合材料力学性能、电导率及摩擦磨损性能的变化规律。结果表明:通过铜基体微合金化处理(添加1wt%Ti),在BNNSs界面处生成了致密且均匀的TiN过渡层和TiB晶须,改善了BNNSs与铜基体的界面结合。BNNSs/Cu-(Ti)-900℃复合材料的抗拉强度为408 MPa,延伸率为15.5%,且电导率仍保持91%国际退火铜标准(IACS)的高水平,摩擦系数降低至0.58(纯铜基体:0.80)。本文所得的铜基复合材料在获得优异力学性能和耐磨性能同时,仍保持良好的导电性,为开发高性能电接触材料及摩擦材料提供了技术指导。

Copper has a wide application prospect in brush and contact materials because of its high conductivity and high ductility.With the rapid development of power transmission industry,the disadvantage of low strength of copper itself cannot meet the demand,and it is urgent to develop a high-strength and high-toughness copper matrix composite material(CMCs)to make up for the defects of copper materials.Boron nitride nanosheets(BNNSs)is expected to be used as good reinforcements for copper matrix composites due to its excellent mechani-cal properties and high temperature structural stability.In this study,BNNSs reinforced copper matrix composites(BNNSs/Cu)with high comprehensive properties were prepared by powder metallurgy.Microstructure and inter-face evolution characteristics of composites at different heat treatment temperatures,as well as the changes of mechanical,electrical and tribological properties were studied.The results show that by matrix microalloying(adding 1wt%Ti)and heat treatment,the dense and uniform TiN interfacial transition layer and nano-TiB whisker are formed at the interface of BNNSs,which improve the interfacial bonding between BNNSs and matrix.Ultimate tensile strength(UTS)of BNNSs/Cu-(Ti)-900'C is 408 MPa,the elongation(EL)is 15.5%and the conductivity remains high level of 91%International Annealed Copper Standard(IACS)and the friction coefficient is 0.58(pure Cu is 0.8).BNNSs/Cu-(Ti)prepared in this study display excellent mechanical properties and wear resistance while maintaining good conductivity,which provide the technical guidance for high performance electrical materials.