高纯铜初始层裂的微损伤特性研究

本文对平面冲击加载下高纯铜初始层裂的微损伤特性进行了研究. 利用准三维的表面轮廓测试技术, 对冲击加载“软回收”的样品截面进行测试. 通过对测试数据的重构、量化和统计分析, 结果表明: 拉伸应力持续时间和加载应力幅值的增加, 都会加剧样品内部损伤局域化程度. 样品内损伤区域宽度是亚微米尺度的损伤演化的结果, 并且亚微米尺度的演化速率随着拉伸应变率的增加而单调递增. 通过统计获得了样品内微损伤的尺寸分布特征, 并分析了其与损伤演化进程的关联.

Micro-damage characteristics of incipient spall in high-purity copper

Dynamic damage of material is a complex process that is dependent on lots of effects on a mesoscale, including grain size, morphology and micro-voids. In order to study the shocked lead micro-damage characteristics in oxygen-free high-purity copper, the variational thickness values of flyers and samples are designed to vary pulse duration and strain rate in plate-impact experiment, and the special recovery chamber and surface profile measurement system are used for soft-recovery and cross-section measure respectively. Based on the reconstruction, quantitative and statistical analysis, it is found that the longer pulse duration and higher shock loading stress bring about more serious local damage in oxygen-free high-purity copper. The mensurable damage width of sample cross-section results from the damage evolution on a sub-micron scale. Critical evolution time of sub-micron is observed to decrease with strain rate increasing, suggesting that damage evolution speed of sub-micron becomes faster as strain rate increases. The void size distribution of recovered sample is presented, and the topological characteristic transition accompanied with nucleation, growth, and coalescence processes of microscopic voids is also discussed. Through a comparison of difference between this work and the literature of previous research, a physical explanation of voids size distribution characteristics of oxygen-free high-purity copper is presented.