Research On The Machining Mechanism Of The Surface Abrasive Air Jet Polishing Of Aviation Aluminum Alloy

The use of 7075 aluminum alloy in aircraft is increasing.The materials of aircraft frame and thin-walled parts are mainly 7075 aluminum alloy.Currently,milling is often used to process such materials.The milling lines produced by the milling process will reduce the service life of aviation aluminum alloy parts.The various drawbacks of traditional aluminum alloy surface polishing methods limit its application in the field of aviation aluminum alloy surface polishing.As a new type of material surface polishing technology,abrasive air jet polishing has significant advantages in surface polishing of aircraft frames and thin-walled parts with complex structures.In this paper,medium-hardness amino thermoset plastic particles are used as abrasives for polishing,and the surface of 7075 aluminum alloy is polished by abrasive gas jet polishing technology,and a new type of aviation aluminum alloy surface polishing process is explored.It is the abrasive gas jet polishing technology in aviation aluminum alloy.Provide technical support for the application of surface polishing.The main research work and results completed in this paper are as follows:1.The abrasive gas jet polishing theory and experiment are introduced,and the velocity model and impact depth model of abrasive particles are established.At the same time,the orthogonal test was also designed.The surface roughness of the aluminum alloy was used to measure the quality of the test results.It was found that the spray pressure has a relatively large influence on the surface roughness of the aluminum alloy.When the spray pressure is 0.3 MPa and the spray angle is When 70°and the spraying distance is 8 cm,the surface roughness obtained is relatively small.2.This article explored the single abrasive particle cutting mechanism,surface material removal mechanism and abrasive wear microscopic mechanism,and found that its removal mode is a mode of coexistence of cutting and extrusion.3.The effect of abrasive gas jet treatment on the surface integrity of aluminum alloy is studied.The study found that when the spray pressure is 0.3 MPa,the surface roughness of aluminum alloy is relatively low,Ra=1.547 ?m,and the surface roughness of aluminum alloy is reduced by about 60%.When the spray pressure is 0.5 MPa,the surface hardness of the aluminum alloy is 288.65 HV,an increase of about 30%.When the injection pressure is 0.3 MPa,the residual compressive stress is introduced on the surface of the aluminum alloy,and its value is 437.44 MPa.When the spray pressure is 0.5 MPa,a residual compressive stress of-1073.9 MPa is introduced on the surface of the aluminum alloy,which is about 10.39%higher than that of the aluminum alloy without spray treatment.4.The relationship between the surface wear resistance of aluminum alloy and spray pressure was studied,and it was found that when the spray pressure is 0.4 MPa,the surface wear resistance of aluminum alloy is relatively better,and the friction coefficient is 0.665,which is comparable to that of unsprayed aluminum alloy surface.Compared with the wear resistance,its wear resistance increased by approximately 12.15%.When the spray pressure is 0.2 MPa,the aluminum alloy surface wear resistance is relatively poor,and the friction coefficient is 0.8.Compared with the surface wear resistance of the aluminum alloy without spray treatment,its wear resistance is about 5.7%lower.