论文标题
CR-Si-B系统中的T2相位位点占用：合并的同步量XRD/第一原理研究
T2 phase site occupancies in the Cr--Si--B system: a combined synchroton-XRD/first-principles study
论文作者
论文摘要
在密度函数理论（DFT）的范围内，对CR-SI-B系统中T2相的硼和硅位点占用进行了实验研究。一个名义成分cr $ _ {0.625} $ b $ _ {0.175} $ si $ _ {0.2} $的样本在argon下进行了弧形，并用石英管封装，并在1400°C下进行热处理96小时。然后使用扫描电子显微镜（SEM）和X射线衍射法（XRD）用同步辐射分析。在实验和理论计算之间达成了一项良好的一致性，表明SI优选地占据了由于存在弱B键而导致的结构的$ 4A $ sublattice，这使得站点偏好成为其稳定的关键因素。这项工作的结果提供了重要的信息，以支持Si和B合金中此阶段的更好描述，因为已知T2阶段发生在许多重要的过渡金属 - SI-SI-B三元系统中，例如NB/MO/MO/MO/MO/W/W/TA/V-SI-B。
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.
