Dynamic Mechanical Properties And Fracture Failure Behavior Of 3003 Aluminum Alloy

Aluminum alloy is the most widely used automotive lightweight metal material.In the context of actual engineering,the failure of automotive aluminum alloys often occurs at high speeds,so it is necessary to study the dynamic mechanical properties and fracture failure of aluminum alloys.In order to deeply understand the dynamic mechanical properties of 3003 aluminum alloy and the deformation and fracture characteristics of the tensile process,and obtain the relationship between the parameters of the MJC constitutive equation and the dynamic mechanical properties of the material,6061-T6 aluminum alloy and DX56D+ZM high-strength steel are used for comparison.In this paper,dynamic tensile testing machine combined with digital image correlation technology(DIC)is used to obtain the dynamic mechanical properties of three materials;SEM and other instruments are used to observe and analyze the fracture and side metallographic structure of the sample after stretching;in order to study different stress states In this paper,the GISSMO equation of 3003 aluminum alloy is established for the fracture failure of 3003 aluminum alloy under the following conditions;in view of the fact that the Johnson-Cook constitutive equation cannot fit the curve after necking well,the modified Johnson-Cook constitutive equation(MJC);In order to verify the correctness of the GISSMO equation and the MJC equation,this paper established a finite element simulation model for the cupping test of 3003 aluminum alloy.The main research contents are as follows:(1)Through the dynamic tensile experiment of 3003 aluminum alloy with different strain rates,it is found that with the increase of the strain rate,the strength of the 3003 aluminum alloy is improved to a certain extent,and the plasticity is significantly enhanced.The flow stress of3003 aluminum alloy increases in two stages with the increase of strain rate.(2)Through the analysis of the fracture SEM and side metallographic structure of the three materials,it is found that with the increase of the strain rate,the tearing edge of the fracture of3003 aluminum alloy decreases,the diameter of the larger dimples increases and the number decreases,and the fracture area It decreases with the increase of the strain rate;the grain shape of the fracture side is more slender than the undeformed metal,and with the increase of the strain rate,there is a trend of further expansion.(3)Through the comparison of stress triaxiality experiment and simulation curve,the relationship curve between stress triaxiality and fracture strain is obtained.By comparing with the experimental curve,it is found that the MJC constitutive equation can predict the curves of the three materials well after the necking.The fitting results show that the stronger the strain rate sensitivity of the material is,the higher the C value is in the MJC constitutive equation.Larger;the better the plasticity of the material,the smaller the value of m is in the MJC constitutive equation.(4)By comparing the 3003 aluminum alloy cupping test results with the simulation simulations of the three equations of JC,MJC,and JC compound GISSMO equations,it is found that the finite element simulation and test results of the JC constitutive equation fitting curve of 3003 aluminum alloy The overall match is poor.The finite element simulation and test results of the two equations fitting curves of MJC and JC compound GISSMO of 3003 aluminum alloy match well as a whole,which proves the reliability of the two constitutive equations.