| In this article, the wrap of cupper on ferric(Fe-20Cu) matrix were prepared as friction material by hot pressing sintering method with addition of Al powder, graphite and MoS2. Effect on microstructure and properties was investigated under dry friction. Wear mechanisms of the friction material in different rotate speeds were analyzed. Braking process of automobile clutch and brake made by the friction materials was simulated using numerical simulation method.The results obtained indicate that:The matrix is the wrap of cupper on ferric (Fe-20Cu) that has some impacts on the microstructure of the friction material for inhibiting interaction between Fe and the additive. With addition of Al into Fe-20Cu, new phase of AICu4, solid solution of CuFe and AlCu, and there is no intermetallic compound of Fe-Al form. And with addition of graphite in the material, sintered microstructure composes of ferrite, pearlite, secondary cementite, graphite and cementite formed. Hinder of diffusion of carbon by wrapped cupper leads to increase of residual graphite and decrease of cementite. With addition of graphite and MoS2, the material composes of Fe, Cu and precipitates secondary cementite, CuS and small amounts of Fe-Mo solid solution. However wrap of cupper on ferric inhibits formation of phase of FeS.Wear mechanism of the Fe-20Cu based friction material changes with the additives and rotational speed. In low rotational speed, wear mechanism of adhesive wear of Fe-20Cu friction material containing graphite and MoS2weakens, and the wear mechanism mainly manifests as fatigue wear. While In high rotational speed, wear mechanism of materials manifest as abrasive wear, oxidation wear and fatigue wear, but the broke of friction controlled by fatigue wear.Temperature and thermal stress during the braking process of the brake made by the Fe-20Cu-3%Al-3%graphite-3%MoS2friction material were simulated by numerical simulation. The results show interaction effect between temperature field and thermal stress field. |
PDF Full Text Request