ABSTRACT The present work verifies the structural instability of θ’ precipitates, a primary strengthening phase in aged Al-Cu alloys, using atomic-scale imaging. A periodic structure of the precipitate has been found around the semi-coherent interface. In addition, the experimental results also show that the structure of the shear-resistant precipitate can be modified by long-time electron beam irradiation in the transmission electron microscope. During the process, stacking faults will be introduced in both the precipitates and the matrix, and a step with a height of four atomic layers will be formed on the coherent interface between precipitates and matrix.

中文翻译：

---

时效Al-Cu合金中板状θ'析出物的结构不稳定性

摘要 目前的工作使用原子级成像验证了 θ' 析出物的结构不稳定性，这是时效 Al-Cu 合金中的主要强化相。在半相干界面周围发现了沉淀物的周期性结构。此外，实验结果还表明，在透射电子显微镜下长时间电子束照射可以改变抗剪切沉淀物的结构。在此过程中，析出物和基体都会引入堆垛层错，并在析出物和基体的相干界面上形成一个高度为四个原子层的台阶。