Study On Surface Quality And Corrosion Resistance Of ZL114A Aluminum Alloy Based On Turning

Cast aluminum alloys are often used in aerospace manufacturing because of its high specific strength,good machinability and low density.ZL114 A aluminum alloy is a common material for aeroengine structural parts.During the cutting process of ZL114 A aluminum alloy structural parts,the surface of the workpiece is prone to defects,which makes the engine structural parts more likely to be corroded during service,and the service life of the aeroengine is seriously affected.Therefore,it is of great significance to study the surface quality and corrosion resistance of ZL114 A aluminum alloy workpieces under dry cutting condition.In this paper,the surface quality and corrosion resistance of ZL114 A aluminum alloy bars were taken as the research object.Based on the turning experiments and electrochemical corrosion experiments,combined with the analysis of cutting heat,cutting force and tool wear state,the effect of turning parameters and tool nose radius on the surface quality and corrosion resistance is explored.The main research contents are as follows:(1)Based on the single factor experiment method and the orthogonal experiment method,the turning processing experiment was carried out on the ZL114 A aluminum alloy workpieces.The cutting force and the cutting temperature were measured by thermocouple and three-way piezoelectric dynamometer,and the effects of turning parameters and tool nose radius on the cutting force and the cutting temperature of ZL114 A aluminum alloy were studied under the dry cutting condition at room temperature.It is found that turning depth and feed rate have great influence on the cutting force and turning depth has great influence on the cutting temperature.(2)Microscope was used to observe chip morphology and tool morphology,and the effects of turning parameters and tool nose radius on tool wear and chip morphology were analyzed from the point of view of thermo-mechanical coupling.The research shows that carbide turning tool cutting ZL114 A aluminum alloy is prone to adhesion wear;the tool flank wear VB is most sensitive to the change of spindle speed;the chip shape obtained by aluminum alloy turning is mainly banded chips.(3)Based on observation instruments such as ultra-depth-of-field microscope and X-ray diffraction,the aluminum alloy workpieces after turning were observed.Combining with tool wear,the effects of turning parameters and tool nose radius on the workpieces were studied from the perspective of thermal-mechanical coupling.The influence law of surface roughness,surface topography,surface residual stress and surface microhardness was established,and the regression equations of surface quality characterization parameters were established.The experimental results show that the surface roughness increases the most with the change of turning depth and feed rate;the surface residual stress is compressive stress,which is sensitive to the change of tool nose radius.The surface microhardness does not show an obvious change rule with the change of machining parameters;There are obvious tool marks on the machined surface,accompanied by the appearance of grooves.(4)The machined surface was electrochemically corroded in 5.0wt.%NaCl electrolyte,and the corrosion resistance of the machined surface of ZL114 A aluminum alloy was studied.It is found that with the increase of spindle speed and the decreas of tool nose radius,the corrosion resistance of the machined surface is better.