We have investigated symmetrical tilt boundaries spontaneously introduced by compressing layer-structured Al-Cu eutectic alloys, based on scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and crystal plasticity (CP) analysis. SEM observations show sine-wave-like bending of a layered structure consisting of soft Al and hard AlCu phases and sharp symmetric tilt boundaries appeared only in the Al layers at the corner of the waves. TEM/STEM observations revealed that the tilt-boundaries consist of a single variant of dislocations, the feature of which is similar to the kink boundary that normally occurs in anisotropic crystals such as hexagonal close-packed. CP analysis indicated that differences in plastic deformation capacity between the Al and AlCu layers cause selective activation of slip systems in soft Al layers, which induces rotational deformation accompanied by the spontaneous formation of kink boundaries.

中文翻译：

---

层状结构 Al-Cu 共晶合金中应力引起的对称倾斜边界

我们基于扫描电子显微镜 (SEM)、透射电子显微镜 (TEM)、扫描透射电子显微镜 (STEM) 和晶体塑性 (CP) 分析，研究了通过压缩层状结构 Al-Cu 共晶合金自发引入的对称倾斜边界。SEM观察显示，由软Al和硬AlCu相组成的层状结构呈正弦波状弯曲，并且仅在波角处的Al层中出现尖锐的对称倾斜边界。TEM/STEM 观察表明，倾斜边界由单一位错变体组成，其特征类似于通常出现在各向异性晶体（例如六方密堆积）中的扭结边界。CP分析表明，Al和AlCu层之间塑性变形能力的差异导致软Al层中滑移系统的选择性激活，从而引起旋转变形并伴随着扭结边界的自发形成。