Damage Mechanisms Perspective on Superior Ballistic Performance of Spinel over Sapphire
Damage Mechanisms Perspective on Superior Ballistic Performance of Spinel over Sapphire
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DOI：
10.1007/s11340-012-9634-0
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发表时间：
2013
影响因子：
2.4
通讯作者：
E. J. Haney;G. Subhash
中科院分区：
文献类型：
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作者：
E. J. Haney;G. Subhash
蓝宝石和镁尖晶石是两种常用的透明装甲材料。虽然人们普遍认为，较好的机械性能往往会导致较好的现场性能，但据报道，尖晶石的弹道性能优于蓝宝石，尽管其机械性能较差。根据冲击加载时的变形机理，对上述差异进行了合理化分析。在回顾了报道的尖晶石和蓝宝石的弹道性能结果后，我们将讨论相关的力学性能及其无法解释所观察到的矛盾行为。然后，我们将展示静态（15 s持续时间）和动态（100 μs持续时间）压痕断裂特征的差异，并将这些观察结果与球对杆冲击试验中观察到的断裂模式进行比较。最后，比较了每种材料在各种变形机制中吸收的能量，得出了尖晶石有趣行为的基本原理。在球的冲击过程中，蓝宝石沿晶面的断裂允许大量碎片喷射出来，造成结构完整性的严重损失和更深的穿透力，而尖晶石的混合模式断裂产生的细碎片与来袭的弹丸相反，导致球的严重减速和侵蚀。从而为尖晶石优于蓝宝石的性能提供了一个基于机理的理论依据。
Sapphire and magnesium spinel are two commonly used transparent armor materials. Although it is commonly believed that better mechanical properties often result in better field performance, the ballistic performance of spinel is reported to be superior to sapphire despite its inferior mechanical properties. The above discrepancy has been rationalized on the basis of mechanisms of deformation during impact loading. After reviewing the reported ballistic performance results on spinel and sapphire, we will discuss the relevant mechanical properties and their inability to explain the observed paradoxical behavior. We will then present differences in static (15 s duration) and dynamic (100 μs duration) indentation fracture characteristics and compare these observations to fracture modes witnessed during ball-on-rod impact tests. Lastly, the energy absorbed in various deformation mechanisms for each material is compared to draw a rationale for the intriguing behavior of spinel. Fracture along crystallographic planes in sapphire during ball impact allows large fragments to be ejected causing a significant loss in structural integrity and deeper projectile penetration, whereas the mixed mode fracture in spinel produces fine debris which opposes the incoming projectile and causes severe deceleration and erosion of the ball. Thus a mechanism based rationale has been provided to describe the superior performance of spinel over sapphire.