Formation of Stable Schwarz Crystals in Polycrystalline Copper at the Grain Size Limit
Formation of Stable Schwarz Crystals in Polycrystalline Copper at the Grain Size Limit
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DOI：
10.1103/physrevlett.127.136101
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发表时间：
2021-09-20
影响因子：
8.6
通讯作者：
Lu, K.
中科院分区：
文献类型：
--
作者：
Jin, Zhaohui;Li, Xiuyan;Lu, K.
最近在超细晶多晶Cu中发现了一种由共格孪晶界（CTB）约束的分割空间最小晶界（GB）的原型施瓦茨晶体（SC）结构。在这封信中，三维CTB网络对SC的形成和热稳定性的约束作用通过原子模拟来解决。GB的迁移和CTB网络的演化触发了SC金刚石的形成。CTB约束对于产生零平均曲率的几何边界层和平衡晶格的弹性驱动力是至关重要的。在接近熔点的温度下，GB运动可以被抑制，GB孔径低至3 nm。
A prototype Schwarz crystal (SC) structure of dividing-space minimal grain boundaries (GBs) constrained by coherent twin boundaries (CTBs) was recently discovered in extremely fine-grained polycrystalline Cu. In this Letter, constraining effects of 3D CTB network on the formation and thermostability of SC are addressed via atomistic simulations. GB migration and evolution of CTB network trigger formation of SC diamond. CTB constraints are critical to generate GBs of zero mean curvature underlying vanishing capillary pressure, and to counterbalance the elastic driving forces of lattice. GB motion can be suppressed at temperatures close to the melting point with GB aperture down to 3 nm.