Effect Of Heat Treatment Process On Machinability Of 7075 Aluminum Alloy

Aluminum alloy is a common high-strength alloy material,which is widely used in aerospace and automotive industrial sectors,with high strength and good corrosion resistance.However,in an environment with high temperature,large pressure,fast speed,any defects of the surface layer have a significant impact on the work of workpieces.This article is based on 7075 aluminum alloy,based on orthogonal and single factor cutting experiment and abaqus finite element simulation.Exploring the influence of different heat treatment status on its cutting process and surface integrity,the cutting amount of 7075 aluminum alloy surface roughness,processing hardening,residual stress,tool wear and chip forms in different heat treatment are explored.And based on the scanning electron microscope(SEM)and X-ray diffraction XRD,the evolution of the microstructure after cutting was discussed.First,through the Hopkinson dynamic impact test,draw a stress strain curve based on different temperature and strain rates.And established a 7075 aluminum alloy based on the stress strain curve.The two-dimensional cutting of 7075 aluminum alloy is then constructed based on the sufficient equation,and the cutting simulation analysis is performed based on the orthogonal experimental scheme.Second,the heat treatment of 7075 aluminum alloy is carried out.The influence of cutting parameters on its machinability is explored,the effect of cutting parameters on the cutting force and cutting temperature of 7075 aluminum alloy in different heat treatment states during the cutting process,and the law of influence on the surface roughness,work hardening degree and residual stress of the workpiece after the cutting is completed.The results show that the machinability of 7075-T6I4 aluminum alloy is better than that of 7075-T6 and 7075-T6I6.And the factor that has a greater impact on cutting force and cutting temperature isa_p,and its optimal cutting parameters arev_c=750 m/min,a_p=1 mm,f_z=0.06 mm/z.At the same time,the surface roughness decreases with the increase of the cutting speed,but the feed rate is positively related to the surface roughness,and the cutting depth has no significant effect on the surface roughness;The work hardening and residual stress of the cutting surface of 7075 aluminum alloy were also studied.Under the same cutting parameters,the order of the maximum residual compressive stress is:7075-T6>7075-T6I4>7075-T6I6,and the order of the maximum residual tensile stress is reversed.The cutting speed is negatively related to the degree of hardened layer of the workpiece material and the depth of the hardened layer of work.The depth of cut is positively correlated with the depth of the work hardening layer of 7075 aluminum alloy.However,the degree of work hardening decreases with the increase of the depth of cut.At the same time,the depth of the work hardening layer and the degree of work hardening have no obvious correlation with the feed rate,and the influence law is more complicated.In the cutting process,the residual stress is mainly manifested as residual compressive stress,and the maximum residual compressive stress of 7075aluminum alloy with different heat treatments has a positive correlation with cutting parameters,and the maximum residual stress has a negative correlation with cutting parameters.Thirdly,using the S-3400N scanning electron microscope,we explored the influence of different cutting parameters on tool wear and chip morphology during the cutting process.The results show that in the cutting process of 7075 aluminum alloy,the main forms of tool wear are rake face wear and flank wear,and the manifestation is chipping.At the same time,the chips in the cutting process mainly appear as band-shaped chips,and the chip deformation is most affected by the cutting speed and feed rate.With the increase of cutting speed and feed rate,the chip deformation and the degree of bending increase.Finally,the microscopic surface morphology of 7075 aluminum alloy under different heat treatment conditions was studied.As the cutting speed increased and the feed rate decreased,the surface finish of the workpiece was improved.However,the depth of cut has no significant effect on the surface finish of 7075 aluminum alloy.Through X-ray diffraction and other microscopic inspection methods,the processed surface deterioration layer and microstructure of 7075 aluminum alloy were analyzed.The results show that the stability of 7075 aluminum alloy after T6I4 heat treatment is better,and its Al peak height is significantly higher than that of the other two states of aluminum alloy.