Research On The Improvement Of Surface Tribological Properties Of Aluminum-tin Bearing Alloy By Laser Shock Micro-modeling

Aluminum-tin alloy bearing has the advantages of good thermal conductivity,corrosion resistance,high bearing capacity.It is the preferred material for the bearing bush.And due to frequent conversion during the procedure to start and stop of the bearing,it leads to a serious consequence-wear and tear damage,causing a shutdown accident.This paper tries to find the solution to use the laser impact technology in order to improve the friction performance of the material surface and reduce the negative impact of friction and wear.The main work is as below:(1)Based on the Comsol numerical simulation,it studied the influence of texture distribution area,initial rotation speed,crater size and other parameters on oil film pressure,oil film bearing capacity and axis trajectory at startup and stabilization stages.The result showed the oil film convergence area had better lubrication performance and stability at the startup stage.Meanwhile,the oil film pressure and bearing capacity was gradually decreased with the increase of rotating speed,and the roundness of the axis trajectory was also increased.In the stabilization stage,when the pit spacing was 1.4mm,the dislocation was 0.5 mm and the depth/diameter ratio was 0.0683,the oil film had the best dynamic pressure lubrication performance.(2)Based on the laser impact experiment,it also studied the influence of laser process parameters on the size of texture.The relationship between the improvement of mechanical properties and wear resistance was explored.The study also found the change rule of the diameter and the depth of the pit.During the procedure of increase of the laser energy,most of the diameter and the depth of the pit will be increased firstly and then decreased.When the laser energy was 1.8 J for 5 shocks,the pit diameter reached a maximum of 1141.307?m.When the laser energy was 1.6 J for 7 shocks,and the maximum pit depth reached a maximum of 80.307 ?m.If the laser energy was enhanced and added the impacts,the surface roughness of the material will be increased.The maximum size was 2.1137 ?m.The surface vickers hardness of Al-Sn alloy was significantly improved.Compared with the matrix hardness the maximum in the direction of radius and depth was 106.7% and 90.0%respectively.After laser shock,a grain refining layer of a certain depth appeared in the Al-Sn alloy in the direction of depth,and the maximum influence layer depth was 28.14 ?m.(3)Based on the experiment of friction and wear,it studied the influence law of speed and texture parameters on surface lubrication and friction performance.It was found whenthe lubrication state of the texture sample was critical at 360 r/min.Compared the friction morphologies of the texture and smooth samples,the friction and wear mechanisms of different lubrication states were analyzed.It took the single factor method to explore the micro modelling spacing,dislocation,deep diameter ratio on the aluminum tin alloy friction and wear performance.The study found when under the situation of the boundary lubrication and the perfect lubrication,the average friction coefficient and wear quantity lubrication condition with indentation spacing,dislocation,the increase of depth to diameter ratio,increases with the decrease of the first priority,the corresponding optimal characteristic value is dislocation pits of spacing of 1.4 mm and 0.5 mm,depth to diameter ratio of 0.0683 respectively.The experimental results matched the numerical results,and the correctness of the numerical results is verified.