金属玻璃纳米晶化机制研究进展

Progress in Understanding Nanocrystallization Mechanism of Metallic Glasses

金属玻璃是一类具有结构和功能应用前景的新型金属材料,是目前物理和材料学科最为活跃的研究领域之一。由于处于热力学亚稳态,金属玻璃在合适的外界条件下会自发地向相应的晶态相发生转变,导致晶化事件的发生。研究金属玻璃的纳米晶化不仅有重要的科学意义,同时也可对金属玻璃的应用提供理论指导。简要介绍了目前几种代表性的金属玻璃纳米晶化微观机制:经典形核理论、基于耦合通量模型的形核机制、基于相分离的纳米晶形核长大机制、有序原子集团沉积机制、非经典形核理论、大过冷度条件下纳米晶化的微观机制等,同时结合作者课题组近年来在这方面的研究进展,对各种机制进行了评述,最后对未来金属玻璃纳米晶化机制研究中需要重视的几个问题进行了简单展望。

Metallic glasses, as a new class of metallic materials with potential applications in structural and functional aspects, are one of the hottest topics in the field of physics and materials science. Since they are metastable thermodynamically, metallic glasses always transform into their crystalline counterparts spontaneously under some suitable conditions, leading to the occurrence of crystallization event. The research on nanocrystallization of metallic glasses not only is of scientific importance, but also offers theoretical guidance for applications of these materials. In this paper, we give a brief review of several representative micromechanisms for nanocrystallization of metallic glasses, including classical nucleation theory, nucleation mechanism based on the linked-flux model, nucleation and growth mechanism associated with phase separation, cluster deposition micromechanism, non-classical nucleation theory, and nanocrystallization micromechanism under a larger undercooling. Moreover, our recent progress in understanding the atomistic mechanism for nanocrystallization of metallic glasses is also reviewed. Finally, we point out a couple of issues that deserve further investigation to fully understand nanocrystallization behaviors of metallic glasses.