Anisotropic behavior of as-extruded 7003 aluminum alloy under quasi-static compression and high-speed impact

Abstract

The anisotropic behavior of as-extruded 7003 aluminum alloy under quasi-static compression and high-speed impact was studied using samples with axes parallel to extrusion direction (ED) (0° sample), at an angle of 45° to ED (45° sample), and perpendicular to ED (90° sample). The experimental results show that the yield stress of the 0° sample is the highest, while the 45° sample is the lowest. Compared with other samples, the 90° sample is more sensitive to the applied strain rate, which experiences a rapid failure after reaching peak stress under high-speed impact. Under quasi-static compression and high-speed impact, the 0° sample exhibits nearly uniform deformation, while the 45° and 90° samples exhibit anisotropy behavior. Due to the occurrence of adiabatic shear, the plastic deformation anisotropy in 45° and 90° samples under high-speed impact is more significant compared to quasi-static compression. For the 45° and 90° samples, the r values, which characterize plastic deformation anisotropy, decrease from 0.77 to 0.82 under quasi-static compression to 0.46 and 0.40 under high-speed impact. In addition, adiabatic shear bands are observed in all deformed samples under high-speed impact, while only the 90° sample fractures. Due to the significant difference in Schmidt factors along ED and transverse direction (TD), plastic deformation of the 90° sample under high-speed impact is mainly concentrated in TD, while the deformation in ED is very small. The extremely uneven deformation leads to earlier nucleation and faster development of ASBs in TD, causing the 90° sample to fracture under high-speed impact.