论文标题
冲击压缩的纳米聚晶钻的前所未有的流动强度
Unprecedented flow strength in shock-compressed nano-polycrystalline diamond
论文作者
论文摘要
钻石是最难的天然材料，因此为材料设计提供了独特的见解。极端压力和温度会产生条件，即使钻石等强大而脆弱的材料也可以变形并表现出流动强度，即对塑料流的抗性。尽管进行了大量研究，但在高能量条件下钻石材料中流动强度的上限仍然不确定，而推动变形的机制是激烈争论的主题。在这里，我们证明了堆叠型托运介导的增强使纳米聚晶钻石（NPD）达到107+-5 GPA的峰值流量强度。通过冲击载荷到多兆巴应力实现，这种前所未有的流动强度与准稳态压缩的NPD相比提高了五倍。我们的飞秒原位X射线衍射（XRD）实验和大规模的分子动力学仿真探测了这一现象。我们的工作表明，通过使材料处于最极端的条件下，我们可以解锁异常的强度和机械性能。
Diamond is the hardest natural material and thus offers unique insights into materials design. Extreme pressures and temperatures create conditions that allow even strong and brittle materials like diamond to deform plastically and exhibit flow strength, i.e., resistance to plastic flow. Despite significant research, the upper limit of flow strength in diamond materials under high energy conditions remains uncertain, and the mechanisms driving the deformation are a subject of intense debate. Here, we demonstrate that stacking-fault mediated strengthening enables nano-polycrystalline diamond (NPD) to achieve a peak flow strength of 107+-5 GPa. Achieved through shock loading to multi-megabar stresses, this unprecedented flow strength represents a five-fold increase compared to that of quasi-statically compressed NPD. Our femtosecond in situ X-ray diffraction (XRD) experiments and large-scale molecular dynamics simulations probe this phenomenon mechanistically. Our work shows that by subjecting materials to the most extreme conditions, we can unlock unusual strength and mechanical properties.
