Non-orthogonal Slip-line Field Cutting Model Of Metallic Glasses Resreach

As new engineering materials,metallic glasses,also called amorphous alloys,have an important application prospect in the military,space and other fields due to their excellent physical,mechanical and chemical properties.Their unusual long-range disorder,medium-range order atomic configurations make different experimental results of ordinary crystalline metal occur during cutting machining,such as tension and compression asymmetry and pressure and temperature sensitivity.Cutting force is an important aspect of cutting mechanism research,the original cutting model is suitable for metallic glass because of its special microstructure.Some people have attempted to established cutting force model for metallic glass,however,the accuracy of the model is not high.Based on the analysis of deformation characteristics of metallic glass,proposed a generalized M-C yield criterion of temperature correction and introduced it to the slip-line field cutting model,Specific studies are as follows:1.On the basis of comparative analysis of deformation yield criterion of metallic glasses,and because of the similarity of metallic glasses microstructure and macroscopic disorder structure of rock and soil internal particle,the M-C yield criterion that apply to the field of rock and soil mechanics is introduced into the deformation of metallic glass cutting yield.At the same time considering the double sensitivity of temperature and stress of metallic glass,and such issue that the M-C yield criterion neglect the effect of intermediate principal stress,the M-C yield criterion has been amended,and proposed a “generalized M-C yield criterion of temperature correction” that applied for describing the cutting deformation process of metallic glasses2.Establishment of cutting model is an important method to present the mechanical behavior during cutting process,and the plastic flow status of materials could be accurately reflected by slip-line field model.In this paper,applying revised yield criterion for slip-line field model,the orthogonal characteristic of cutting slip-line field are altered because of the double sensitivity of temperature and stress of metallic glass,so non-orthogonal slip-line field model that research on cutting mechanism of metallic glasses is established.To solve the analytical model,the thickness and width of chips have been measured after turning experiments,and the thermodynamic analysis method that shear work converted into cutting temperature on the shear plane is used to solve the average temperature formula in cutting model.3.The use of cutting force measured data is compared to verify the above model.The experimental results show that,under the same cutting parameters,cutting model in the relevant literature,slip-line field model that not considered intermediate principal stress,and slip-line field model that considered intermediate principal stress,the latter has the highest accuracy,the average error of 8.9%.The experimental results demonstrate the validity of the theoretical modeling work.4.Different from cutting mechanical phenomena of crystalline metal has been found by orthogonal cutting force experiments,that the main cutting force of traditional definition was not the maximum component force during cutting metallic glasses,but the thrust force slightly bigger than the main cutting force.The possible reason may be related to the characteristic of low elastic modulus of metallic glasses,it is also one of the important reasons that appearing acutely worn on flank face.