Influence of localized alloy composition tailoring by laser-induced element evaporation on the mechanical properties of aluminum alloy AA7075

Abstract

As the demand for lightweight materials in industries such as automotive and aerospace grows, high-strength aluminum alloys are essential to meet stringent performance requirements. While these alloys offer an excellent strength-to-weight ratio, they often face challenges in terms of formability, limiting their broader applicability. This investigation advances beyond conventional Tailor Heat Treated Blanks (THTB) by adjusting the chemical composition in forming-critical areas, such as transitions, radii, and flange zones. Tailor Alloyed Blanks (TAB) provide an approach for adapting both microstructure and elemental distribution, surpassing the capabilities of traditional thermal treatments. This study explores the application of Tailor Alloyed Blank to AA7075, with limited formability, demonstrating its local modification toward the properties of a more ductile 6xxx series alloy. By optimizing laser parameters, selective evaporation of zinc (Zn) and magnesium (Mg) was achieved, leading to enhanced ductility without compromising the base material’s strength. This approach enables the creation of regions with tailored strength and ductility profiles, allowing local adjustments in critical areas. The findings indicate that local modifications of the alloy composition improve formability, as evidenced by reduced forming forces and lower springback behavior observed in the forming trial. This principle can be extended to other precipitation-hardening alloys, provided that their mechanical behavior is governed by alloying elements whose addition or removal is physically feasible via thermal evaporation, based on their boiling points. These results establish a framework for achieving targeted mechanical properties, positioning it as a novel method for tailoring aluminum alloys requiring customized material properties.