Effect of Cutting Speed on the Microstructure and Performance of Pure Copper Nanocrystalline Chips in Large Strain Machining
Large Strain Machining(LSM)causes the workpiece material to be sheared by the cutting edge and squeezed by the rake face to produce severe plastic deformation to form high-strength ultra-fine-grained chips.The finite element software Deform-3D was used to simulate the large strain cutting of pure copper,and the influence of cutting speed on equivalent strain,equivalent strain rate and temperature was analyzed under the rake angle of 20°and-20°.Through LSM tests,with the help of electron backscatter diffraction(EBSD)technology and Vickers hardness testing,the microstructure and mechanical properties of pure cop-per chips at different cutting speeds were studied.The experimental results show that with positive and negative rake angles,as the cutting speed increases,the equivalent strain decreases,and the equivalent strain rate and cutting temperature rise,and the equivalent strain rate and cutting temperature are more affected by the cutting speed;The grain size obtained under the-20°tool is mainly distributed below 0.35μm,the dislocation density has a significant downward trend,and the hardness value is reduced from 162.8HV to 114.8HV.The grain size obtained under the 20°tool is mainly distributed between(0.2～0.6)μm,the disloca-tion density changes little.The hardness value is reduced from 163.8HV to 146.8HV.Compared with the positive rake angle,the cutting speed has a more severe effect on the grain size,dislocation density and hardness of the ultrafine-grained chips prepared by the negative rake angle tool.
Large Strain CuttingCutting SpeedMicrostructureMechanical Properties
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NSTL
万方数据
维普
