Correlation Between Microstructure And Mechanical Properties Of Single Crystal/ Double Crystal Aluminum

In this paper,based on molecular dynamics simulation and dislocation theory at the atomic scale,the effect of the interaction between several micro structures in the material on the mechanical properties of the material is studied.The mechanical behavior of bi-crystal aluminum in the process of stretching and pressing is studied.The influence of the distribution and number of defects on the deformation mechanism and the strength of the material is analyzed.Then,the bypass mechanism of dislocations and precipitated phases was numerically simulated.The process of precipitation strengthening and dislocation proliferation was observed at the atomic scale.The effects of the size,distribution and number of precipitated phases on the precipitation strengthening effect were discussed.The mechanical behavior of the twin crystal aluminum with line vacancy defects during the tensile process was studied,and the influence of factors such as the relative distance between the line vacancy defects and the grain boundary and the defect spacing were considered.Line vacancy defects will weaken the connection of the grain boundary and reduce the tensile strength of the double crystal aluminum.The smaller the relative distance between the defect and the grain boundary,the greater the impact on the tensile properties of the material,and will change the interface damage mode.When the defect spacing is small,the defects in the stretching process will merge with each other to create voids,induce fracture,and reduce the tensile strength of the material.Based on the research of online vacancy defects,this paper further studies the effect of dislocations on the mechanical properties of double-crystal aluminum.In the process of temperature relaxation of the model,the crystal orientation on both sides of the grain boundary will affect the mechanical behavior of dislocations in the double crystal aluminum.Under tension,when the crystal orientation difference on both sides of the crystal interface remains unchanged,the dislocations will weaken the connection of the grain boundaries and reduce the tensile strength of the double crystal aluminum,but when the crystal orientation difference on both sides of the crystal interface decreases the tensile strength of the twin crystal aluminum is improved.In the case of shearing,the slip mechanism of dislocations leads to a decrease in the shear resistance of the twin crystal aluminum model.The greater the number of dislocations,the lower the shear strength.In view of the precipitation strengthening effect during the material processing,the interaction between dislocations and precipitated phases in face-centered cubic aluminum during shearing was studied.The presence of the precipitated phase will lead to the phenomenon of dislocation proliferation,which can enhance the shear resistance of the material.The larger the size(mass fraction)of the precipitated phase and the more uniform the distribution,the better the precipitation strengthening effect and the stronger the shear resistance.When other parameters are kept unchanged and the number of precipitated phases is increased,the shear resistance of the material is significantly enhanced.In this paper,by studying the effect of structural changes on the mechanical properties of materials at a micro scale,and explaining the mechanism,it has a guiding significance for the actual production and processing of materials.