Pusan National University Study Reveals Why Mg Alloy Ballistic Performance Depends on Impact Direction

New study reveals how crystallographic texture and impact direction shape the ballistic response of lightweight AZ31 magnesium alloys

BUSAN, South Korea, Oct. 6, 2026 /PRNewswire/ -- 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 was made available online on September 26, 2026, and will be published in Volume 24 of the Journal of Magnesium and Alloys on November 01, 2026.

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, using plates 5–20 mm 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. Prof. 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. Prof. Lee noted, "Instead of inventing a new alloy or adding weight, engineers can boost ballistic resistance simply by orienting the plate so that impacts arrive along the direction in which its texture promotes uniform, symmetric deformation. This is essentially "free" performance extracted from material that already exists." Such orientation-aware design could support lighter, more impact-resistant Mg alloy components for military vehicle panels, protective structures, and other weight-sensitive applications.

Overall, the study identifies crystallographic texture and component orientation as important design variables for the ballistic performance of textured Mg alloys. By linking crystal-scale deformation with stress localization and macroscopic fracture, the findings provide a basis for exploring texture-engineered lightweight protective structures. Further research will be needed to determine how the approach performs under more complex, real-world impact conditions.

Reference
Title of original paper: Orientation-dependent ballistic response of textured Mg alloy plates: From deformation mechanisms to macroscopic fracture
Journal: Journal of Magnesium and Alloys
DOI: 10.1016/j.jma.2026.102287

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SOURCE Pusan National University