Study On The Fragmentation And Dispersion Behavior Of Al₂O₃ Inclusions Based On Cohesive Zone Model

Heavy forgings are the key parts for the development of national major technical equipment.Their quality and mechanical properties are related to the independent manufacturing capacity and technical level of national equipment.However,harmful non-metallic inclusions are inevitable in the process of steel ingot smelting and pouring.In order to improve the performance of forgings,it is urgent to study the fragmentation and dispersion of non-metallic inclusions in steel.In this paper,Al₂O₃ inclusions in steel were used as the research object,the 3D representative voxel model is established based on Linux system,and the cohesive zone model of Al₂O₃ inclusion is constructed based on the traction displacement damage fracture criterion,and the cohesive element is embedded in the inclusion voxel based on python programming.Through the hot compression test on Gleeble-3800 thermal simulator,the true stress-strain curves of Al₂O₃ inclusions at different temperatures and strain rates were measured.According to the hot compression test,the finite element model of high temperature compression is established and the numerical simulation is carried out.By comparing the results of hot compression finite element simulation and hot compression test,the cohesive zone model parameters of Al₂O₃ inclusions under different temperature and strain rate were determined.Based on the finite element sub-model technique and cohesive zone model,a simulation model of cylindrical upsetting process with inclusions was established.The effects of forging temperature,deformation region,shape and size of inclusions on the fracture of inclusions in the matrix were analyzed.The deformation of the forging required for the fracture of Al₂O₃ inclusions in the forging was obtained.The upsetting process conditions for breaking the Al₂O₃ inclusion in forgings under different influence factors are given.With the help of finite element sub-model technique and particle tracking method,the influence of different forging temperature,deformation area and inclusion size on the dispersion distance of inclusions after crushing was studied,and the relationship between the dispersion distance of inclusions and the forging deformation under different deformation conditions was established.The influence of sub-inclusions on matrix stress distribution under different forging temperature,deformation zone and size of sub-inclusions is analyzed.The deformation conditions and corresponding upsetting process conditions are obtained to ensure that the stress affected zone of sub-inclusions does not overlap each other.