Study On Effect Laws Of Surface Integrity For 7075 Aluminum Alloy By Wire Electrical Discharge Machining

7075 aluminum alloy is widely used in aerospace,automotive and shipbuilding industries for its high specific strength,excellent thermal conductivity,easy processing,corrosion resistance and many other advantages.It is difficult for traditional processing to achieve special parts with 7075 aluminum such as complicated surface,thin wall,micro hole and deep groove and so on.There is no cutting force produced in the process of electric discharge machining,so this paper uses WEDM to process 7075 aluminum alloy.And the surface integrity of processed parts will directly affect the service life of parts,therefore,the study of surface integrity of parts is particularly important.In this paper,in order to study the effect laws of surface integrity for 7075 aluminum alloy that is processed by WEDM,Mild-speed Wire Electrical Discharge Machining(MS-WEDM)is used to carry out studies on processing technology index(area removal rate,roughness and machining accuracy),recast layer(geometric parameters,elements,micro-structure and residual stresses),friction and wear properties under different conditions(dry friction and salt solution)and corrosion resistance through orthogonal experiment,single factor test,friction and wear test and electrochemical experiment.Experimental results show that:(1)When the electric parameters are optimal,which pulse width is 8 mu s,pulse time is 64 s and power tube is number 3,the surface integrity of workpiece is the most balanced;(2)The wear resistance of the workpiece under different conditions is all significantly better than the substrate itself;(3)The corrosion resistance of the processed workpiece is also better than that of the substrate itself.