Dynamics of solidification in Al thin films measured using a nanocalorimeter
Dynamics of solidification in Al thin films measured using a nanocalorimeter
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DOI：
10.1063/1.3668128
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发表时间：
2011-12
影响因子：
3.2
通讯作者：
P. Swaminathan;D. Laván;T. Weihs
中科院分区：
文献类型：
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作者：
P. Swaminathan;D. Laván;T. Weihs
我们演示了如何纳米热量计可以用来测量薄膜熔化和凝固的动态使用铝作为模型系统。当热释放速率快于热提取速率时，观察到由于凝固时的焓释放而导致的温度升高的再辉。对于薄膜，在界面处具有大密度的成核中心，在高冷却速率下观察到吸热效应，其中直接测量热容和焓变具有挑战性。使用纳米量热计芯片施加104 K/s的温度速率;纳米量热计允许直接测量冷却不足、固化期间的温度升高以及相关的焓变化。这项工作突出了物理测量中的一些挑战，并提供了一个数值策略来评估快速凝固过程中的焓变化。
We demonstrate how a nanocalorimeter can be used to measure the dynamics of thin film melting and solidification using aluminum as a model system. Recalescence, a rise in temperature due to enthalpy release on solidification, is observed when the rate of heat release is faster than the rate of heat extraction. For thin films, with a large density of nucleation centers at the interface, recalescence effects are observed at high cooling rates where direct measurements of heat capacities and enthalpy changes are challenging. Temperature rates of 104 K/s were applied using nanocalorimeter chips; the nanocalorimeter allows direct measurement of the under cooling, temperature rise during solidification, and the associated changes in enthalpy. This work highlights some of the challenges recalescence causes in physical measurements and provides a numerical strategy to evaluate enthalpy changes during rapid solidification.