Study on the tensile properties of Al-Zn-Mg alloy based on molecular dynamics

Abstract

To explore the mechanical properties of Al alloy under fire or high-temperature environments and ensure its safety in practical applications, this study investigates the failure mechanisms and deformation behavior of Al alloy under tensile loading from a microscopic perspective. Molecular dynamics (MD) simulation method is employed to examine the failure behavior of Al alloy, revealing the failure mechanisms at the microscale and the variations in alloy’s mechanical properties under different loads. These findings lay a theoretical foundation for subsequent research on high-temperature resistant Al alloys. The study reveals that Al alloy exhibits a tensile strength of 6.89 GPa at 300 K, with a low occurrence of dislocations during the early stages of tension and a relatively long stage of elastic deformation. As the temperature rises, at 700 K, the tensile strength decreases to 4.42 GPa, representing a reduction of 35.84%. The elastic modulus also decreases from 62.84 GPa to 33.19 GPa. The mechanical properties of aluminum alloys are significantly influenced by temperature changes. The increase in temperature intensifies atomic motion, accelerating the diffusion rate of atoms in the alloy. This leads to thermal expansion of the material and changes in the bonding forces between atoms, thereby affecting the mechanical properties of the material. The yield stress of Al alloy exhibits a positive correlation with strain rate; with an increase in strain rate from 0.001 ps−1 to 0.02 ps−1, the tensile strength increases from 6.54 GPa to 7.04 GPa. Therefore, appropriately increasing the strain rate can enhance the material’s mechanical performance.