In this work, the mechanical response and fracture characteristics of (TiZrBeAlCu)Co high-entropy bulk metallic glass (HE-BMG) were investigated in detail over a wide range of strain rates (10–10 s). The HE-BMG exhibited a negative strain rate sensitivity under uniaxial compression, with the strength showing more significant rate dependence under dynamic conditions. The shear band behavior translated from the dominance of multiple shear bands propagations under quasi-static compression to the rapid propagation of a single shear band to form cracks under dynamic compression. Under dynamic loading, the shearing velocity increased along an arc-shaped displacement path, and the local stress state on the shear fracture surface shifted from compressive-shear to tensile-shear, accompanied by changes in fracture morphologies. The spall strength of HE-BMG decreased as flyer impact speed increased, while the long-term dependence of spall strength on strain rate may be positive. With the increase of impact speed, the main microstructural features of the spalling surface translated from flat regions accompanied by dimples to cup-cone structures. Furthermore, the complete parameters of the Johnson–Holmquist II (JH-2) model for HE-BMG were obtained based on experimental data. Numerical simulations of planar impact, penetration, and hypervelocity impact are in good agreement with experimental results, demonstrating the validity of the JH-2 model parameters. The current work has important guiding value for the application of HE-BMG in space debris protection.

中文翻译：

---

(Ti37.31Zr22.75Be26.39Al4.55Cu9)94Co6高熵块体金属玻璃动态力学响应及本构模型


在这项工作中，详细研究了 (TiZrBeAlCu)Co 高熵块体金属玻璃 (HE-BMG) 在各种应变速率（10-10 秒）下的机械响应和断裂特性。 HE-BMG 在单轴压缩下表现出负应变率敏感性，在动态条件下强度表现出更显着的速率依赖性。剪切带行为从准静态压缩下多个剪切带传播的主导转变为动态压缩下单个剪切带快速传播形成裂纹。动载作用下，剪切速度沿弧形位移路径增加，剪切断裂面局部应力状态由压剪向拉剪转变，并伴随断裂形貌的变化。 HE-BMG 的剥落强度随着飞片冲击速度的增加而降低，而剥落强度对应变率的长期依赖性可能是正的。随着冲击速度的增加，剥落表面的主要微观结构特征从伴有韧窝的平坦区域转变为杯锥结构。此外，根据实验数据获得了 HE-BMG 的 Johnson–Holmquist II (JH-2) 模型的完整参数。平面撞击、侵彻和超高速撞击的数值模拟与实验结果吻合较好，证明了JH-2模型参数的有效性。目前的工作对于HE-BMG在空间碎片防护中的应用具有重要的指导价值。