Tribological Performance Research Of Micro-dimple Texture Under Lubrication

Surface texture is widely concerned because of its properties of improving tribological performance.Water and seawater,as "green" lubrication mediums,have great significance and development prospect.In this paper,laser processing was used to build micro-dimple texture of cone frustum on Ti6A14V alloy surface.The tribological performance of micro-dimple texture of cone frustum was investigated by the experiments under water,seawater and oil lubrications.Based on Reynolds equation,mathematical model of micro-dimple texture of cone frustum was built,which is used to simulate and calculate the effect of geometric parameters of micro-dimple and working condition parameters on the carrying capacity of lubricating film.Finally,the optimal geometric parameters of micro-dimple texture of cone frustum were obtained.The main research contents and results are shown as follows:The experiment results show that the friction coefficient under water lubrication is the biggest one on the smooth surface,the second is seawater lubrication,and the third is oil lubrication.However,the wear loss under seawater lubrication is the largest,the second is water lubrication,and the third is oil lubrication.The tribological performance of micro-dimple of cone frustum with spacing of 200?m is better than that with spacing of 300?m.Compared with the smooth surface,the friction coefficient of cone frustum whose spacing is 200 ?m reduces by 8.6%,5.7%and 60.0%,and the wear loss reduces by 44.0%,35.9%and 25.0%under water,seawater and oil lubrications,respectively.The tribological performance of micro-dimple of cone fruustum with depth of 40 ?m is better than that with depth of 20?m.Compared with the smooth surface,the friction coefficient of cone frustum whose depth is 40 ?m reduces by 19.5%,18.8%and 73.3%,and the wear loss reduces by 59.4%,53.0%and 47.0%under water,seawater and oil lubrications,respectively.The simulation results show that the asyrnmetric pressure is distributed in the lubricating film which is located on a micro-dimple calculation region of cone frustum.Therefore,the extra carrying capacity is provided between the relative sliding surfaces.The bigger the carrying capacity of lubricating film is,the smaller the friction coefficient will be.With the decrease of the spacing of micro-dimple,the carrying capacity of lubricating film increases.With the increase of the depth of micro-dimple,the carrying capacity of lubricating film increases first and then decreases.There is an optimal depth of 60 ?m which correspond to the maximum carrying capacity of lubricating film.Moreover,with the increase of the small radius of micro-dimple of cone frustum,the carrying capacity of lubricating film increases first and then decreases.And there is also an optimal small radius of 70 ?m which correspond to the maximum carrying capacity of lubricating film.The carrying capacity of lubricating film increases linearly as the increase of the relative speed between the friction pair,and the increasing rate is proportional to the viscosity of lubrication medium.In addition,the carrying capacity of lubricating film increases linearly as the increase of the viscosity of lubrication medium.In a word,the simulation results provide strong theoretical basis for the results of experiment.