This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Magnesium (Mg) alloys offer a pathway to lighter, more efficient aerospace and defense structures because of their low density, high specific strength and excellent damping capacity. However, their hexagonal close-packed (HCP) crystal structure makes deformation highly dependent on crystallographic orientation.
Processing-induced texture can further amplify this anisotropy, meaning that the same alloy can respond differently depending on the direction of loading. Understanding this relationship is therefore essential to unlocking the full potential of Mg alloys. While anisotropy in the quasi-static mechanical behavior of Mg alloys has been extensively studied, how this anisotropy governs deformation and fracture during high-velocity ballistic impact remains poorly understood.
To address this gap, researchers from Pusan National University, led by professor Taekyung Lee, in collaboration with Seoul National University and Kyungpook National University, investigated how impact direction and crystallographic texture influence the ballistic performance and fracture behavior of AZ31 Mg alloy. The study is published in the Journal of Magnesium and Alloys. Researchers tested hot-rolled AZ31 Mg alloy plates with a strong basal texture under high-velocity impacts along the normal direction (ND) and rolling direction (RD) at ~884 m/s (1,978 miles per hour), using plates 5–20 mm (0.2–0.8 inches) thick.
Projectile velocity, energy absorption, penetration behavior, bulging and fracture morphology were evaluated. Microstructural characterization and crystallographic analysis revealed the position- and direction-dependent deformation mechanisms. Finite-element simulations complemented these observations by mapping stress localization, plastic dissipation and damage accumulation, thereby explaining the localized conditions associated with shear-band formation and fracture.
The findings revealed a striking direction-dependent difference in ballistic performance. Lee explains, "Plates impacted along the ND consistently absorbed 6.5%–6.7% more energy and fractured in a symmetric manner upon perforation. In thicker plates that resisted full perforation, ND impact promoted bulging rather than cracking.
By contrast, impact along the RD produced localized shear bands and asymmetric, elliptical fractures." The contrasting responses arose from distinct deformation mechanisms: ND impacts promoted uniform extension twinning and homogeneous stress distribution, while RD impacts triggered heterogeneous slip and twinning, shear localization, adiabatic heating and dynamic recrystallization. These findings demonstrate that crystallographic texture strongly governs the deformation, energy absorption and fracture of α-Mg alloys under high-velocity impact. The study points to an economical pathway for improving ballistic protection without adding material weight.
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