高纯铝层裂的自由面速度剖面特征分析

 采用任意反射面激光干涉测速（VISAR）系统，对高纯铝（纯度为99.999%）材料开展了层裂实验研究，获得了未完全层裂和完全层裂样品的自由面速度剖面。基于实验测量中观察到的层裂回跳（Pullback）信号的脉冲宽度、速度幅值差异以及回跳信号上升过程中的两次速度斜率变化特征，详细讨论了高纯铝材料从出现损伤到完全断裂的过程中波剖面演化的行为特征。结合“软回收”样品的细观分析，指出这些自由面速度变化特征可能与材料中应力波的能量释放速率以及材料中晶粒的断裂行为密切相关。研究结果可以为延性金属损伤断裂的演化过程提供有意义的认识。

Characteristics Analysis of Free-Surface Velocity Profiles of Ultra-Pure Aluminum

A series of plate impact experiments were conducted to probe into the free-surface velocity profiles characteristics of ultra-pure aluminum (Purity:99.999%) by a velocity interferometer system for any reflector (VISAR). Based on the observed differences of pullback signals in amplitude, pulse width, and two "sudden changes", the wave profile evolution during fracture process of ultra-pure aluminum from incipient spall to complete rupture is discussed in detail. The reasons for these change behaviors are analyzed with the mesoscopic analysis of  "soft-recovery" sample. This paper points out that these characteristics are possibly related to the release rate of stress wave energy and the fracture behavior of material grain. These analysis results are helpful to understand the evolution process of ductile metal dynamic damage.