Study of Wear in a Novel Cu-Based Sintered Alloy for Train Brakes (Influence of Sintered Temperature)

作     者：Glenn Kwabena Gyimah 

作者单位：华南理工大学 

学位级别：硕士

导师姓名：黄平

授予年度：2010年

学科分类：082304[工学-载运工具运用工程] 08[工学] 080204[工学-车辆工程] 0802[工学-机械工程] 0823[工学-交通运输工程] 

摘      要：A novel Cu-based composite frictional train brake material composed of several elements such as Al, SiO2, Fe, graphite, Sn, Mn and MoS2 re-enforced with other elements was treated under Powder Metallurgy （P/M） route. Well prepared powders were hydraulically compacted at 650MPa. The materials were sintered at three different temperatures （850oC, 900oC and 950oC） at a constant pressure. The dry sliding friction and wear characteristics of three different sintering treatment temperatures were investigated and the results were remarkable. The tribological behavior of these materials was analyzed by pad-on-disk tests without lubrication and the coefficient of friction, wear rate and wear number were studied in order to identify the effects of the sintering temperature on the base materials composition. The porosities were found to be very high but were adequate to give the right self lubrication properties and to reduce seizure. It was found that the porosity varies inversely proportional to the increase in sintering temperature. The pores in the sintered material were mainly solid lubricants such as graphite and other low melting elements. This also resulted in poor hardness and mechanical properties, which were compensated by its ability to reduce seizure. Much lower wear frictional coefficient, k and the highest coefficient friction,μwith a high wear number, Wn were obtained, indicating a good wear resistance property of the friction material. Three forms of wear mechanisms were observed during the dry sliding process, namely;delamination wear, plowing wear and abrasive wear. The abrasive wear results in flake or break-away debris. These wear mechanisms were found to be responsible for high wear rates on samples sintered at 850oC and 900oC. Generally, the materials demonstrated excellent brake performance and wear resistance. The average values of friction coefficient under excessive pressure （3.13MPa） dry conditions were 0.336, 0.343, and 0.404, at 850oC, 9