本项目拟采用单辊旋淬结合热压烧结方法制备包含大量低角晶界、调幅分解共格界面及点缺陷等的高热电性能块体RE-Fe-Co-Sb材料。在微米尺度，通过揭示旋淬薄带中柱状晶定向生长的动力学及其在固态转变中晶界特征分布的演化规律，实现在块体材料中低角晶界的调控。在纳米尺度，通过探明非平衡凝固及调幅分解相关性以及调幅分解相的粗化动力学，实现对块体材料中共格界面形貌的调控。在原子尺度，通过揭示Te及Sn等元素的固溶度以及在晶格点阵中站位，实现对块体材料Sb原子的部分置换。在此基础上，采用同步辐射X射线衍射和双球差矫正透射电镜技术对这些组织结构附近的应变起伏进行精确表征。最终建立微米、纳米及原子尺度上的应变起伏与块体材料热电性能的定量关系。这些研究对于发展非平衡液固及固态转变一体化理论和高性能热电材料都具有重要意义。

In this project, a single roll melt spinning combined with hot-pressing sintering method is used to prepare high thermoelectric performance bulk RE-Fe-Co-Sb alloys, which contains a large number of low angle grain boundaries, spinodal coherent phase interfaces and point defects. At the micron scale, by revealing the dynamics of the directional growth of columnar crystals in the spun ribbon and the evolution law of the grain boundary characteristic distribution in the solid state transition, the regulation of the low angle grain boundary in the bulk material will be realized. At the nanometer scale, the correlation of non-equilibrium solidification and spinodal decomposition and the coarsening kinetics of spinodal phase will be discovered to realize the regulation of the spinodal coherent phase interfaces. At the atomic scale, the solid solubility of the doing elements such as Te and Sn will be revealed and their position in the lattice will also be realized, which realizes the partial substitution of Sb atoms in the bulk material. Based on these, the strain fluctuation in the vicinity of these structures will be accurately characterized by the synchrotron X-ray diffraction and transmission electron microscopy with double spherical aberration correction. Finally, the quantitative relationship between the thermoelectric properties of bulk materials and the strain fluctuations on the micron, nanometer and atomic scale will be established. These studies are of great significance for the development of nonequilibrium liquid-solid and solid-state transition theory and high performance thermoelectric materials.