High‐entropy alloys, consisting of multiple principal elements, represent a new paradigm in structural alloy design with excellent mechanical properties and potentially promising ballistic performance. Herein, the ballistic response of a single‐phase Al_0.1CoCrFeNi high‐entropy alloy is evaluated with spherical E52100 steel (RC60) projectiles at velocities ranging from 500 to 1000 m s⁻¹ at normal obliquity, indicating failure by ductile–hole growth. A wide range of microstructural features are observed corresponding to varying degrees of deformation and the corresponding hardness maps are obtained. The microstructure in the partially penetrated condition is dominated by microbanding and microtwinning close to the crater wall. With striking velocity that result in plugging but not complete penetration, the deformation is dominated by twinning and crack initiation around adiabatic shear bands close to the exit hole. A high density of localized adiabatic shear bands and recrystallized grains are observed at impact velocities corresponding to full penetration. Highly deformed areas near the crater wall and narrow zones around shear bands show the maximum hardness, indicating significant work hardening of the material during penetration.

中文翻译：

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Al0.1CoCrFeNi高熵合金的弹道冲击响应

由多种主要元素组成的高熵合金代表了结构合金设计的新范例，具有出色的机械性能和潜在的弹道性能。在此，使用球形E52100钢（RC60）弹丸在500至1000 m s ^-1的速度范围内评估了单相Al _0.1 CoCrFeNi高熵合金的弹道响应在正常的倾斜度下，表明由于孔延性生长而失败。观察到与不同程度的变形相对应的各种微观结构特征，并获得了相应的硬度图。在部分穿透状态下的微观结构主要由靠近火山口壁的微带和微孪晶所主导。撞击速度会导致堵塞，但无法完全渗透，变形主要是由靠近出口孔的绝热剪切带周围的孪生和裂纹萌生引起的。在对应于完全穿透的冲击速度下，观察到了高密度的局部绝热剪切带和重结晶晶粒。弹坑壁附近的高度变形区域和剪切带周围的狭窄区域显示出最大的硬度，