Abstract Nanocalorimetry is an ideal candidate for revealing the crystallization of metallic glass in a wide temperature range attributing to its ultrafast heating rate and ultrahigh sensitivity. In this study, in situ preparation of Ce68Al10Cu20Co2 (at.%) metallic glass was realized by the nanocalorimetry. By the subsequent reheating at the rates from 500 to 40,000 K/s, the crystallization in a wide temperature range was demonstrated. The crystallization activation energy and Avrami exponent are calculated with the aid of the Kissinger and Johnson-Mehl-Avrami (JMA) equations to reveal the temperature-dependent nucleation and crystal growth behavior in the undercooled liquid, where three crystallization regimes are identified. At low temperature, the crystallization occurs with constant activation energy. In an intermediate temperature range, the crystallization is controlled by crystal growth with a reduction of activation energy. At temperatures approaching Tm, an increased activation energy resulting from the thermodynamic driving force dominates the nucleation-controlled crystallization. This study provides a novel strategy to reveal the crystallization behavior in the undercooled liquid from Tg to Tm and to demonstrate the transition from growth-controlled crystallization to nucleation-controlled one with the decrease of undercooling.

中文翻译：

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接近熔化温度：纳米量热法揭示了 Ce68Al10Cu20Co2 块状金属玻璃的非等温结晶状态

摘要 纳米量热法由于其超快的加热速率和超高的灵敏度，是揭示金属玻璃在较宽温度范围内结晶的理想选择。在本研究中，通过纳米量热法实现了 Ce68Al10Cu20Co2 (at.%) 金属玻璃的原位制备。通过随后以 500 至 40,000 K/s 的速率重新加热，证明了在很宽的温度范围内结晶。借助 Kissinger 和 Johnson-Mehl-Avrami (JMA) 方程计算结晶活化能和 Avrami 指数，以揭示过冷液体中温度依赖性成核和晶体生长行为，其中确定了三种结晶状态。在低温下，结晶以恒定的活化能发生。在中等温度范围内，结晶由具有降低活化能的晶体生长控制。在接近 Tm 的温度下，由热力学驱动力引起的活化能增加主导了成核控制的结晶。该研究提供了一种新策略来揭示过冷液体中从 Tg 到 Tm 的结晶行为，并证明随着过冷度的降低，从生长控制结晶到成核控制结晶的转变。