Research On Microstructure And Performance Of Aviation Aluminum Alloy Cutting Surface

Aviation aluminum alloy is widely used in aviation manufacturing industry, because of its High specific strength, good toughness, fatigue resistance and corrosion resistance properties. Integrated structure is adopted in aviation components to improve the strength and reduce weight. This kind of aluminum alloy component with high machining allowance and material removal rate usually adopt high speed machining, in order to improve the machining efficiency.Compared with the traditional machining technology, the plastic of material is shown because of high cutting speed. The metamorphic layer is formed by the movement towards dislocation and the crystal because of the combination of high strain, strain rates and complex stress state in high speed process. The microstructure of the layer directly affects the service performance. In this paper, for meeting the requirements of corrosion resistance and wear resistance in the process of service, combined with the characteristics of high strain, strain rate, and temperature of material in cutting zone of high speed milling, with the help of numerical simulation and experimental research, the microstructure and service performance in cutting layer of high speed milling aviation aluminum alloy was studied in order to support for the aviation aluminum alloy cutting process optimization.The two-dimensional finite element geometry model was established based on the theory of trochoid, for numerical simulation of high speed machining process. The dynamic and static of temperature, stress and so on has been analyzed. The influence of cutting speed and time for temperature and stress has been found. The formation reasons for temperature and stress have been analyzed in combination with three-dimensional geometry motion theory of high speed machining process, machining theory and dynamic mechanical parameters.The surface quality of high speed machining process has been detected using the test method such as optical microscopes, surface roughness meters, Vickers hardness tester. The influence of cutting speed for the machined surface morphology and strain hardening has been mainly analyzed. The machining surface hardening depth has been analyzed and measured. The influence of cutting speed for the hardening has been ensured. The formation mechanism of the surface morphology and work hardening has been analyzed based on the model of surface roughness and dislocation theory.The microstructure and composition of high speed machining process has been analyzed using the test method such as scanning electron microscopy and X-Ray diffraction. The dislocation density and grain size have been calculated based on the modified Williamson-Hall. The quantitative analysis of the dislocation density has been implemented and the change rule of cutting speed of the dislocation density has been analyzed. The formation mechanism of the dislocation density has been analyzed based on the conclusion the early stage of the cutting process research. The micro formation mechanism of the residual stress and work hardening has been analyzed based on the dislocation theory.The corrosion resistance and wear resistance of high speed machining surface have been analyzed using the corrosion test and the friction test. Combining microscopic and macroscopic evaluation indexes, the change rule with cutting speed of corrosion resistance and wear resistance has been analyzed. The micro formation mechanism of corrosion resistance and wear resistance has been analyzed. The results show that the corrosion resistance and wear resistance are obviously improved because of the high cutting speed.