Orava Jiri, Balachandran Shanoob, Han Xiaoliang, Shuleshova Olga, Nurouzi Ebrahim, Soldatov Ivan, Oswald Steffen, Gutowski Olof, Ivashko Oleh, Dippel Ann-Christin, Zimmermann Martin V, Ivanov Yurii P, Greer A Lindsay, Raabe Dierk, Herbig Michael, Kaban Ivan
IFW Dresden, Institute for Complex Materials, Dresden, Germany.
Faculty of Environment, Jan Evangelista Purkyne University in Usti nad Labem, Usti nad Labem, Czech Republic.
Nat Commun. 2021 May 14;12(1):2839. doi: 10.1038/s41467-021-23028-9.
A combination of complementary high-energy X-ray diffraction, containerless solidification during electromagnetic levitation and transmission electron microscopy is used to map in situ the phase evolution in a prototype Cu-Zr-Al glass during flash-annealing imposed at a rate ranging from 10 to 10 K s and during cooling from the liquid state. Such a combination of experimental techniques provides hitherto inaccessible insight into the phase-transformation mechanism and its kinetics with high temporal resolution over the entire temperature range of the existence of the supercooled liquid. On flash-annealing, most of the formed phases represent transient (metastable) states - they crystallographically conform to their equilibrium phases but the compositions, revealed by atom probe tomography, are different. It is only the B2 CuZr phase which is represented by its equilibrium composition, and its growth is facilitated by a kinetic mechanism of Al partitioning; Al-rich precipitates of less than 10 nm in a diameter are revealed. In this work, the kinetic and chemical conditions of the high propensity of the glass for the B2 phase formation are formulated, and the multi-technique approach can be applied to map phase transformations in other metallic-glass-forming systems.
结合高能X射线衍射、电磁悬浮下的无容器凝固和透射电子显微镜，对一种原型Cu-Zr-Al玻璃在10至10 K s速率下进行快速退火以及从液态冷却过程中的相演变进行原位映射。这种实验技术的组合在过冷液体存在的整个温度范围内，以高时间分辨率提供了迄今为止难以获得的对相变机制及其动力学的深入了解。在快速退火时，形成的大多数相代表瞬态（亚稳态）——它们在晶体结构上符合其平衡相，但通过原子探针断层扫描揭示的成分不同。只有B2 CuZr相以其平衡成分存在，并且其生长通过Al分配的动力学机制得到促进；揭示出直径小于10 nm的富Al沉淀物。在这项工作中，阐述了玻璃形成B2相的高倾向性的动力学和化学条件，并且这种多技术方法可应用于绘制其他金属玻璃形成系统中的相变。
