Abstract: 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.

Key words: Copper-based powder, Dynamic performance, Friction material, Friction plate, Laser surface modification, Microstructure, Powder metallurgy