Effect Of Heat Treatment On Surface Integrity And Corrosion Resistance Of 7075 Aluminum Alloy Micromachined

The corrosion resistance,specific strength,and thermal deformation of the ultra-high strength 7xxx series aluminum alloy meet the needs of space shuttles,artificial satellites,and medical devices in various aspects.Nowadays,the fields of healthcare,aerospace,and electronics are all moving towards miniaturization,and the demand for manufacturing small and high-precision parts is becoming increasingly urgent.When processing or surface treating parts,the machined surface is affected by cutting forces,thermal effects,and high strains,such as microcracks,debris accumulation,and lattice distortion,which alter the performance of the processed metamorphic layer.Changing the performance of the metamorphic layer can affect the integrity of the processed surface of the part,reduce its corrosion resistance,and shorten its service life.In view of this,this article explores the effects of heat treatment processes and cutting parameters on the micro machinability,surface integrity,and corrosion resistance of the machined surface of 7075 aluminum alloy.Firstly,heat treatment experiments were conducted on 7075 aluminum alloy in T6state,T73 state,and RRA state.Real stress-strain curves were obtained through mechanical properties experiments,and the corresponding Johnson Cook constitutive parameters for the three heat treatment processes were obtained.Establish a finite element simulation model to conduct micro cutting simulation research on three types of heat treated 7075 aluminum alloy,explore the changes in residual stress,cutting force,and cutting heat,analyze the stress distribution law and the minimum cutting thickness of7075 aluminum alloy.The maximum error between the simulated and experimental values of cutting force under different cutting parameters is 15%,which is within the allowable range.The obtained micro cutting simulation model can be used for subsequent simulation research.Secondly,the machined surface integrity of 7075 aluminum alloy was characterized by means of surface roughness tester,microhardness tester and scanning electron microscope.The surface roughness,machined surface morphology and work hardening of7075-T6,7075-T73 and 7075-RRA aluminum alloys with the change of cutting parameters were studied.The experimental results show that the cutting speed is 200mm/s and the cutting depth is 20μm.Feed rate is 1.25μm/z is used,surface defects can be reduced and surface quality can be improved.Finally,the effects of heat treatment process and cutting parameters on the corrosion resistance of micro machined surfaces of 7075 aluminum alloy were studied through electrochemical corrosion experiments.The results showed that the chemical composition of corrosion products was detected using EDS,and the main component of corrosion products on the alloy surface was Al（OH）₃deposits.With the increase of cutting speed,cutting depth,and feed rate,it is not conducive to improving the corrosion resistance of the machined surface of 7075 aluminum alloy.Under the same cutting parameters,the sample treated with 7075-RRA aging has the best corrosion resistance.Cutting speed of200mm/s and cutting depth of 25μm.Feed rate is 3.75μm/z,7075 aluminum alloy has the best corrosion resistance.