Investigation On Mechanical Properties Of AL2024 Micro Cutting Based On Microstructure

Micro-machining technology has been widely used in the field of micro-machining because of the diversity of machinable materials and the complexity of machinable workpieces.In the field of micro cutting,because the microstructure of the material is in the same or adjacent order of magnitude as the size of the processed material,it will lead to the phenomenon of discontinuity in the cutting process such as intracrystalline cutting.This phenomenon directly results in larger chatter of cutting force,faster tool wear speed and lower surface quality.However,the constitutive model used in conventional cutting does not contain scale variables,and there is a large error in direct prediction of micro cutting process.Based on this,a constitutive model of micro cutting is proposed in this paper.The effect of microcosmic polycrystalline structure and other variables on cutting force was studied.The influence of various factors on cutting force is analyzed.This paper has theoretical and practical engineering significance for studying the theory of micro cutting force and predicting the stability of micro machining process.1)based on Hall’s law of grain boundary hardening effect and conventional metal cutting constitutive model,a micro cutting constitutive model with average grain size d is proposed.The secondary development of the constitutive model of the corresponding material is carried out in the finite element software.By comparing the constitutive models of conventional metal cutting under the same conditions,it is concluded that the grain boundary hardening effect does have an effect on the cutting process within a certain range.The effect decreases with the increasing of d.2)the effects of the average grain size d,the radius of the cutting edge and the ratio λ of the back feed on the cutting force are studied.Taking the standard deviation as the evaluation index of cutting force flutter,the relationship between d,λ and cutting force standard deviation is given.The results of cutting force amplitude-frequency analysis also show that the plow cutting and the grain size of the material caused by the arc radius of the cutting edge will lead to extra high frequency vibration of the cutting force.From another point of view,it is explained that the microstructure of the cutting tool has an effect on the flutter of the cutting force.In addition,considering the uneven grain size of various parts of the material,the flutter effect of the structure of the transition layer and the inner layer on the cutting force is studied,and the effect of the structure of the transition layer and the inner layer on the cutting force is studied.It is found that the higher the grain size inhomogeneity is,the more sharply the average grain size changes and the flutter of the cutting force becomes more serious.3)A turning force measurement experiment with the same parameters as the theoretical cutting model is designed and carried out.The experimental data and the theoretical data verify the accuracy of the constitutive model of micro-cutting and the law of the influence of cutting force.The comparative results show thatThe correlation coefficient of prediction trend between the model and the experiment under the same condition is 0.73,which is higher than that of the conventional cutting constitutive model under the same condition,and the maximum prediction error of the average cutting force with the average grain size is 13.2and the maximum prediction error of the standard deviation is as follows.6.8and conforms to the allowable range of engineering errors.