在地观测在六角紧密包装的中 { {math> } 生期间的原子混合
Yang He1, Zhengwu Fang1, Chongmin Wang2
1Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
Nature communications
|April 6, 2024
概括
六角晶体中的塑料变形涉及双胞胎和原子混合. 这项研究揭示了使用现场TEM在纳米晶体中生结的原子机制,观察了独特的混合模式.
科学领域:
- 材料科学 材料科学 材料科学
- 晶体学 晶体学是指结晶学.
- 纳米技术纳米技术
背景情况:
- 双胞胎结合对于六角密封晶体 (HCP) 的塑料变形至关重要,特别是在低温下.
- 与立方体晶体不同,HCP生需要剪切和原子混合.
- 直接观察这些原子混合,特别是非平面的,一直是一个重要的实验挑战.
研究的目的:
- 直接观察和阐明在HCP纳米晶体中的原子生机制.
- 调查纳米晶体材料在双胞胎形成过程中原子混合的作用.
- 了解在有限几何形状中的常规结合模型的偏差.
主要方法:
- 现场传输电子显微镜 (TEM) 用于捕捉动态变形过程.
- 使用高分辨率成像技术,可视化在双胞胎期间的原子排列.
- 分析的重点是识别双胞胎位移和相关的原子混合.
主要成果:
- 发现纳米晶体中的双胞胎结合主要是由 (b1/2,h1/2) 双胞胎断开连接.
- 伴随这些断开的原子混合发生在沿1/6的替代基底平面上.
- 这些混合偏离了传统的预期,并可能受到纳米晶体自由表面的影响.
结论:
- 这项研究提供了第一个直接的实验观察在HCP rhenium的双胞胎期间的原子混合.
- 在替代基底平面上观察到的独特的混合机制突显了纳米晶体中自由表面的影响.
- 这一发现挑战了现有的HCP材料双胞胎模型,并表明需要对纳米结构系统的理解进行修订.
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