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<p>This study systematically investigates the dynamic mechanical response and microstructural evolution of extruded Mg-Gd-Y-Zr alloys under high-strain-rate conditions, focusing on the effects of varying Gd contents (6.5–8.5 wt%) and strain rate variations (1000–4000&#xa0;s⁻¹) and using microscopic detection methods such as metallographic microscopy (OM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The dynamic mechanical properties of the alloys were analyzed under different strain rates using split Hopkinson pressure bar (SHPB) testing. The results reveal that as Gd content increases, the grain size of the alloy first decreases and then increases. The alloy with 7.5 wt% Gd exhibited the smallest and most uniform grains, averaging approximately 12.4&#xa0;μm. In terms of dynamic impact performance, all alloys demonstrated strong mechanical properties. At 6.5 wt% Gd, the alloy achieved a compressive strength of 603&#xa0;MPa at a strain rate of 4000&#xa0;s⁻¹. Increasing Gd content to 7.5 wt% raised the compressive strength to 625&#xa0;MPa, while further increasing Gd to 8.5 wt% resulted in a compressive strength of around 616&#xa0;MPa. Across all Gd levels, fracture typically occurred along the 45° shear plane relative to the impact direction. Regarding deformation mechanisms, significant variations were observed depending on Gd content and strain rate. At lower strain rates, the number of twins first decreased and then increased with higher Gd content. At higher strain rates, slip and dynamic recrystallization became the dominant mechanisms. The 7.5 wt% Gd alloy exhibited the highest degree of dynamic recrystallization and the finest grain structure, resulting in the best overall dynamic impact performance. This research provides valuable theoretical and experimental insights for optimizing the design and performance of Mg-Gd-Y-Zr alloys under high-strain-rate conditions.</p> Graphic Abstract <p></p>

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Influence of Gd Content on the Microstructure and Dynamic Impact Mechanical Behavior of Extruded Mg-Gd-Y-Zr Alloys

  • 期刊论文

  • 发表日期：

    2025年5月24日

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  • Xuezhao Wang,
  • Ping Zhang,
  • Xiaomin Jiang,
  • Youqiang Wang

摘要

This study systematically investigates the dynamic mechanical response and microstructural evolution of extruded Mg-Gd-Y-Zr alloys under high-strain-rate conditions, focusing on the effects of varying Gd contents (6.5–8.5 wt%) and strain rate variations (1000–4000 s⁻¹) and using microscopic detection methods such as metallographic microscopy (OM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The dynamic mechanical properties of the alloys were analyzed under different strain rates using split Hopkinson pressure bar (SHPB) testing. The results reveal that as Gd content increases, the grain size of the alloy first decreases and then increases. The alloy with 7.5 wt% Gd exhibited the smallest and most uniform grains, averaging approximately 12.4 μm. In terms of dynamic impact performance, all alloys demonstrated strong mechanical properties. At 6.5 wt% Gd, the alloy achieved a compressive strength of 603 MPa at a strain rate of 4000 s⁻¹. Increasing Gd content to 7.5 wt% raised the compressive strength to 625 MPa, while further increasing Gd to 8.5 wt% resulted in a compressive strength of around 616 MPa. Across all Gd levels, fracture typically occurred along the 45° shear plane relative to the impact direction. Regarding deformation mechanisms, significant variations were observed depending on Gd content and strain rate. At lower strain rates, the number of twins first decreased and then increased with higher Gd content. At higher strain rates, slip and dynamic recrystallization became the dominant mechanisms. The 7.5 wt% Gd alloy exhibited the highest degree of dynamic recrystallization and the finest grain structure, resulting in the best overall dynamic impact performance. This research provides valuable theoretical and experimental insights for optimizing the design and performance of Mg-Gd-Y-Zr alloys under high-strain-rate conditions.

Graphic Abstract