Fracture behavior of 7075-T6 aluminum alloy under electromagnetic forming and traditional stamping

7075-T6 aluminum alloy is a high strength aluminum alloy that is widely used in automotive and aerospace manufacturing. Nevertheless, its plastic deformation ability is poor at room temperature. Electromagnetic forming (EMF) is a method dedicated to forming materials at high speed using magnetic force, which can significantly improve their plastic deformation ability. However, it is difficult to understand the dynamic processes of high-speed forming. Herein, finite element models of EMF and quasi-static stamping were developed using the ANSYS and ABAQUS software. The Johnson-Cook constitutive model was used to describe the stress-strain behavior of the material, while the Johnson-Cook damage model was used to describe the fracture behavior of the material and the distribution of the fracture strain. The sheet exhibited a small temperature rise before fracture, which has little effect on the material fracture strain by EMF. After fracture, the temperature increased sharply. Scanning electron microscopy images revealed that the material underwent a melting phenomenon at the fracture location. Numerical simulation results demonstrated that the fracture energy of EMF was three times that of traditional stamping, and the high strain rate is the main factor affecting the fracture strain of the material.

Automated summary

This study investigated the electromagnetic forming process of 7075-T6 aluminum alloy and compared it with quasi-static stamping. Through finite element models and the Johnson-Cook model, it was found that the fracture energy of electromagnetic forming is three times that of traditional stamping, and high strain rate is the main factor affecting the material's fracture strain.