Institute for Shock Physics, Washington State University, Pullman, Washington 99164, USA.
Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, USA.
Phys Rev Lett. 2018 Jun 29;120(26):265503. doi: 10.1103/PhysRevLett.120.265503.
Determining the temporal evolution of twinning and/or dislocation slip, in real-time (nanoseconds), in single crystals subjected to plane shock wave loading is a long-standing scientific need. Noncubic crystals pose special challenges because they have many competing slip and twinning systems. Here, we report on time-resolved, in situ, synchrotron Laue x-ray diffraction measurements during shock compression and release of magnesium single crystals that are subjected to compression along the c axis. Significant twinning was observed directly during stress release following shock compression; during compression, only dislocation slip was observed. Our measurements unambiguously distinguish between twinning and dislocation slip on nanosecond timescales in a shocked hexagonal-close-packed metal.
确定在平面冲击波加载下单晶体中孪生和/或位错滑移的时间演变（纳秒级）是一个长期存在的科学需求。非立方晶体带来了特殊的挑战，因为它们有许多竞争的滑移和孪生系统。在这里，我们报告了在沿 c 轴压缩的镁单晶体在冲击波压缩和释放过程中的时间分辨、原位同步加速器劳厄 X 射线衍射测量。在冲击波压缩后的应力释放过程中直接观察到明显的孪生；在压缩过程中，只观察到位错滑移。我们的测量在纳秒时间尺度上明确地区分了冲击六方密堆积金属中的孪生和位错滑移。
