不同球磨时间下制备的铜基自润滑复合材料力学与摩擦磨损性能研究

Study on Mechanical and Tribological Behavior of Copper-based Self-lubricating Composites Prepared at Different Ball Mill Time

目的研究球磨时间对Cu-WS_(2)自润滑复合材料界面状态的影响,同时提高自润滑材料的力学性能和摩擦磨损性能,提出比较优化的Cu和WS_(2)复合材料制备工艺。方法采用高能球磨与放电等离子体烧结技术,制备铜基自润滑复合材料。采用WDW-100电子万能试验机进行力学实验。采用美国Rtec多功能摩擦磨损试验机进行摩擦学实验。采用XRD和SEM表征不同球磨时间的Cu/WS_(2)复合粉末和烧结后块状复合材料的物相组成和微观结构,并结合EDS表征弯折断口的形貌和磨损形貌,分析球磨时间与复合材料界面状态-力学性能-摩擦磨损性能的内在关系。结果当球磨时间为30 h时,WS_(2)在铜基体中有较好的结合与分布,材料的综合性能最佳,WS_(2)/Cu复合材料的力学性能良好,平均摩擦系数为0.186,维持在较低水平,且磨损率最低,为7.11×10^(-5)mm^(3)/(N·m)。球磨时间超过30 h时,磨损率不再与力学性能保持一致,而是随着球磨时间的延长而逐渐提高。球磨时间达到50 h时,基体耐磨性下降,磨损率显著提高,达最大值,为10.39×10^(-5)mm^(3)/(N·m)。结论球磨时间的延长会使WS_(2)在基体中的弥散程度增强,且WS_(2)与Cu基体由于机械互锁式的物理结合增强,使得力学性能随之增强。此外,摩擦磨损性能也能维持在较好水平。但当球磨时间超过30 h时,界面反应加剧,WS_(2)分解为Cu_(2)S,大大减弱了WS_(2)的润滑减摩性能,使得复合材料的摩擦磨损性能降低。

The work aims to study the effect of ball milling time on the interface state of Cu-WS_(2)self-lubricating composites,and at the same time improving the mechanical properties and friction and wear properties of self-lubricating materials,and proposes a more optimized preparation process of Cu and WS_(2)composites.The copper-based self-lubricating composite material was prepared by high-energy ball milling and spark plasma sintering technology.The mechanical experiment was carried out by the WDW-100 electronic universal testing machine.The tribological experiment was carried out by the American Rtec multifunction friction and wear tester.The phase composition and microstructure of WS_(2)/Cu composite powders with different milling time and sintered bulk composites were characterized by XRD and SEM.And combined with EDS,the morphology and wear morphology of the bending fracture were characterized,and the internal relationship between the ball milling time and the interfacial state-mechanical properties-friction and wear properties of the composite material was analyzed.The results indicate that as the ball milling time is 30 h,WS_(2)particles have a better combination and distribution in the copper matrix,and the overall performance of the materials is the best.The mechanical properties of the WS_(2)/Cu composite are good,and the average friction coefficient is 0.186,which is maintained at a low level.The wear rate is the lowest at 7.11×10^(-5)mm^(3)/(N·m).Moreover,as the milling time exceeds 30 h,the wear rate is no longer consistent with the mechanical properties,and increases with the prolonging of the milling time.When the ball milling time reaches 50h,the wear resistance of the matrix decreases and the wear rate increases significantly,reaching the maximum value of 10.39×10^(-5)mm^(3)/(N·m).The extension of the milling time will increase the dispersion of WS_(2)in the matrix,and the mechanical interlocking physical combination of WS_(2)and Cu matrix will enhance the mechanical properties.In addition,the friction and wear performance can also be maintained at a good level.But when the milling time exceeds 30 h,the interfacial reaction intensifies and WS_(2)decomposes into Cu_(2)S,which greatly weakens the lubrication and antifriction properties of WS_(2),and reduces the friction and wear properties of the composite material.