Study On The Surface Texture Structure Of Aluminum Alloy And Its Mechanical Properties Based On MIMST Process

Due to valuable properties of Aluminum and its alloys such as low density,high specific strength,easy processing and molding,this material is widely used in different applications including aviation,aerospace,shipbuilding,automobile,and other fields.By developing the national defense science and technology,the requirements for improved mechanical properties of aluminum and its alloy is increased.Surface modification technology,specifically controlling the surface texture,can effectively improve the bearing capacity,tribological properties,and increase the service life.Considering several issues of the existing texture preparation technologies such as high cost,being time-consumable and non-sustainable,this study proposed an innovative surface modification technique namely,Micro/nano Incremental Mechanical Surface Treatment(MIMST).It can be an effective method for the preparation of the surface texture and improvement of the tribological behavior of Al and other alloys.Thus,the main objectives and achievements are as follows:(1)For the MIMST process,a mathematical model of surface texture prepared by this process is constructed,and the texture unit is defined.The surface texture unit was numerically simulated based on the MATLAB platform.The analysis of the results shows that the cutter speed and feed speed have a greater impact on the texture base length and the texture angle.The single-layer depression and the tool straightness percentage respectively the main effect of texture depth and texture height.(2)Experimental research on surface texture preparation was carried out using 7075-T6 aluminum alloy as a sample.A four-factor three-level orthogonal test was designed to analyze the texture morphology,surface roughness,and surface hardness.The morphological characterization found that the texture topography basically matched the shape of the model constructed in MATLAB,and the relative error of the texture unit size parameters was basically controlled below 15%;the performance test results showed that the deeper the texture,the higher the surface roughness.And the surface hardness of textured aluminum alloy is improved.(3)Under the conditions of rotating friction low load,medium load and high load,the effects of process parameters on the surface friction coefficient of the tool speed,feed speed,single-layer depression and tool straight percentage during the MIMST preparation were experimentally investigated.The analysis shows that the trapped wear debris effect of the surface texture inhibits the generation of furrow effect,thereby extending the retention time of the surface texture and thus reducing the average friction coefficient.The process parameters were optimized by orthogonal test range analysis and covariance analysis.(4)Under the condition of reciprocating friction,the effects of MIMST process parameters on the surface friction coefficient when the grinding angle is 0 °,45 °,and 90 ° are experimentally studied.The analysis shows that the abrasive wear is obvious when the facing angle is 0°,and more abrasive particles are captured by the surface texture when the facing angle is 45 °.When the facing angle is 90 °,the wear mechanism is caused by Abrasive wear is transformed into adhesive wear.The influence of process parameters on the coefficient of friction was also explored through range analysis and covariance analysis.The overall optimization of the process parameters was also considered by considering the micro hardness and the coefficient of friction,and the coefficient of friction and process parameters were constructed.A mathematical model between multiple nonlinear regression.The research results of this paper provide a new idea for the preparation technology of surface texture.The optimization of MIMST texture process parameters and the discussion of the wear reduction mechanism can provide a certain reference for the subsequent surface texture design.