Quasicrystals and their approximants have triggered widespread interest due to the challenge of solving their complex crystal structures as well as their possibly exceptional properties. The structural motifs of approximants are similar to those of the corresponding quasicrystals, but to what extent are their crystallization pathways the same? Unfortunately, there have been very few in situ experimental investigations to answer this question. Here, by leveraging the high penetrating power of hard X-rays, synchrotron-based X-ray tomography was conducted in order to capture the nucleation and growth of a decagonal quasicrystal and its related approximant. The combination of data-driven computational analysis with new thermodynamic databases allowed the characterization, with high precision, of the constitutional and kinetic driving forces for crystallization. The experimental results prove that the growth of both crystals from a liquid is dominated by first-order kinetics. Nevertheless, and somewhat surprisingly, significant differences were observed in their rates of nucleation and growth. The reasons for such divergent behaviours are discussed in light of contemporary theories of intermetallic crystallization.

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Al-Co-Ni 系统中准晶相和近似相的凝固动力学的并排比较

由于解决其复杂晶体结构及其可能的特殊性质的挑战，准晶体及其近似晶体引起了广泛的兴趣。近似体的结构基序与相应的准晶体相似，但它们的结晶途径在多大程度上相同？不幸的是，已经很少有就地实验研究来回答这个问题。在这里，利用硬X射线的高穿透力，进行了基于同步加速器的X射线断层扫描，以捕获十方准晶及其相关近似晶体的成核和生长。数据驱动的计算分析与新的热力学数据库相结合，可以高精度地表征结晶的构成和动力学驱动力。实验结果证明两种晶体从液体中的生长均受一级动力学支配。然而，令人有些惊讶的是，在它们的成核和生长速率方面观察到显着差异。根据当代金属间结晶理论讨论了这种不同行为的原因。