Cr-Si-B系中T2相位的同步-XRD/第一性原理研究
T2 phase site occupancies in the Cr--Si--B system: a combined synchroton-XRD/first-principles study
摘要：
在密度泛函理论（DFT）范围内，通过实验和第一性原理电子结构计算，研究了Cr-Si-B系统中T2相的硼和硅占位。将具有标称组成Cr $_{0.625}$ B $_{0.175}$ Si $_{0.2}$的样品在氩气下电弧熔化，封装在石英管中并在1400 ℃下热处理96小时。然后使用扫描电子显微镜（SEM）和X射线衍射仪（XRD）与同步辐射进行分析。实验和理论计算之间获得了很好的一致性，揭示了Si优选占据结构的$4a$亚晶格，由于弱B键的存在，使网站偏好的一个关键因素，其稳定。这项工作的结果提供了重要的信息，以支持更好地描述该相在合金中的Si和B，因为T2相是已知的，出现在许多重要的过渡金属-Si-B三元系，如Nb/Mo/W/Ta/V-Si-B。
英文摘要：
Boron and Silicon site occupancies of the T2 phase in the Cr-Si-B system were investigated experimentally and by first-principles electronic-structure calculations within the scope of the Density Functional Theory (DFT). A sample with nominal composition Cr$_{0.625}$B$_{0.175}$Si$_{0.2}$ was arc-melted under argon, encapsulated in a quartz-tube and heat-treated at 1400°C for 96 hours. It was then analyzed using Scanning Electron Microscopy (SEM) and X-Ray Diffractometry (XRD) with synchrotron radiation. An excellent agreement was obtained between experiments and theoretical calculations, revealing that Si occupies preferably the $4a$ sublattice of the structure due to the presence of weak B bonds, making the site preferences a key factor for its stabilization. The results of this work provide important information to support a better description of this phase in alloys with Si and B, since T2 phases are known to occur in many important Transition Metal-Si-B ternary systems, such as Nb/Mo/W/Ta/V-Si-B.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
