Abstract：
Using in situ atomic-resolution scanning transmission electron microscopy, atomic movements and rearrangements associated with diffusive solid to solid phase transformations in the Pt-Sn system are captured to reveal details of the underlying atomistic mechanisms that drive these transformations. In the PtSn4 to PtSn2 phase transformation, a periodic superlattice substructure and a unique intermediate structure precede the nucleation and growth of the PtSn2 phase. At the atomic level, all stages of the transformation are templated by the anisotropic crystal structure of the parent PtSn4 phase. In the case of the PtSn2 to Pt2Sn3 transformation, the anisotropy in the structure of product Pt2Sn3 dictates the path of transformation. Analysis of atomic configurations at the transformation front elucidates the diffusion pathways and lattice distortions required for these phase transformations. Comparison of multiple Pt-Sn phase transformations reveals the structural parameters governing solid to solid phase transformations in this technologically interesting intermetallic system.
摘要：
使用原位原子分辨率扫描透射电子显微镜，捕获了与Pt-Sn系统中扩散的固-固相变相关的原子运动和重排，以揭示驱动这些相变的潜在原子机制的细节。在PtSn4到PtSn2相变中，周期性超晶格亚结构和独特的中间结构先于PtSn2相的成核和生长。在原子层面,转变的所有阶段都由母体PtSn4相的各向异性晶体结构模板化。在PtSn2到Pt2Sn3变换的情况下，产物Pt2Sn3的结构中的各向异性决定了转化的路径。在转换前沿对原子构型的分析阐明了这些相变所需的扩散途径和晶格畸变。多个Pt-Sn相变的比较揭示了在这个技术上有趣的金属间体系中控制固-固相变的结构参数。
