CO_2激光表面改性处理对重载荷铜基粉末冶金摩擦片组织及性能的影响

Effect of CO_2 Laser Surface Modification on the Microstructure and Property of Heavy Load Copper-based Powder Metallurgy Friction Plates

针对重载荷铜基粉末冶金摩擦片对动态性能的更高要求,采用宽带激光束对摩擦片铜基粉末冶金摩擦材料层进行激光表面改性处理研究。采用扫描电镜、透射电镜、X射线衍射仪及硬度计等分析、测试仪器对粉末冶金摩擦材料层微观组织及性能进行表征,采用离合器摩擦元件动态性能试验台对摩擦片动态性能进行测试。结果表明,宽带激光表面改性处理后,铜基粉末冶金摩擦材料层的微观结构发生明显的变化,摩擦片的动态性能得到显著改善。聚合生长状态的α-Cu产生边缘溶解,大体积聚合态α-Cu细小化;在α-Cu相内部生成了大量的纳米晶体;铜基粉末冶金摩擦材料层密度提高了6%,表观硬度提高了12.7%,α-Cu相显微硬度提高了14%;摩擦片静摩擦因数提高了7.4%,动摩擦因数提高了9.2%,磨损量降低了33%,磨损率降低了49.6%,许用热负荷值提高了40%。

The copper-based powder metallurgy friction plates are treated by broad-beam laser. The microstructure and hardness of the powder metallurgy friction material layer are characterized by using scanning electron microscope, transmission electron microscopy, energy dispersive spectrometer, X-ray diffraction and hardness tester. The performances of the copper-based powder metallurgy friction plate are tested by using the clutch friction element dynamic performance tester. The results show that after the laser surface modification the α-Cu aggregate occurs edge dissolved and the large aggregates of α-Cu are dismembered to small mass, in the α-Cu aggregate the nanocrystals are discovered. And the layer density of friction material increases by 6%, the apparent hardness increases by 12.7%, the microhardness of the α-Cu increases by 14%. And for the friction plate treated by laser surface modification, the static friction coefficient increases by 7.4%, the kinetic friction coefficient increases by 9.2%, the wear loss reduces by 33%, the wear rate reduces by 49.6%, the allowable heat-load value increases by 40%. The performances of the copper-based powder metallurgy friction plate are improved obviously by laser surface modification.