Mesoscopic Response Behavior Modeling And Simulation Of Heat Resistant Stainless Steel X8CrNi25-21

With the widely application of micro parts in the aerospace, micro-electronics, environment, communications, automotive, biotechnology and many other fields, higher demands have been made toward mesoscopic processing, thus gathering more attention from researchers worldwide to the study of the phenomena and mechanisms of mesoscopic scale cutting process. The study is mainly focused on mesoscopic scale material testing and mesoscopic scale cutting. Mesoscopic scale study isn’t the sheer scaling down from macro scale. Many aspects have to be taken into consideration when it comes to mesoscopic scale study, such as size effect, the influence of microscopic parameters and minimum thickness cutting. So micro plasticity mechanics theory and material dislocations have to be put forward for simulation analysis and experimental research.Firstly, based on plastoelasticity and dislocation dynamics, this paper modify the classical constitutive model Johnson-Cook(JC), a constitutive model which can reflect the scale effect and mesoscopic response behavior is established. Introduced dislocation pile-up model, experiments had been made including quasistatic tension and SHPB Experimental, taking microscopic parameters such as crystal size and crystal orientation into account.Secondly, do material test using nonstandard part and appropriately heat treatment to change the grain size. The paper establish mesoscopic constitutive model by determining the parameter in the model.Thirdly, ABAQUS FEM material subroutine is developed with Fortran language. The VUMAT subroutine was developed based on the material constitutive model mentioned above and the elastic-plastic theory in mechanics of material, which was later integrated into ABAQUS to verify its accuracy.Finally, in order to verify the accuracy and rationality of the mesoscopic scale constitutive model, a micro cutting test was carried out experimentally and numerically on the heat resistant stainless steel X8CrNi25-21 with a cemented carbide cutter.The results show that the material can be seen as homogeneous and isotropic in the stage of plastic deformation of the macroscopic polycrystalline materials. The behavior of deformation depends on the grain size as well as the sample size. With the sample size decreasing and the grain size increasing, the heterogeneity of the materials increases. The property of the single anisotropic grain have a great influence on the process of the whole material, which reflects the size effect and the hardening effect is stronger than bating effect that caused by the hole of the grain. In the process of correction, a hardening part increasing with the strain was added in the classical constitutive model. Through the mesoscopic scale material testing and mesoscopic scale cutting, compared with the results of the FEM simulation, we concluded that the modified model is in good agreement with the experimental results.