低熔点金属相变材料的熔点和相变潜热的理论预测

Prediction of Melting Temperature and Latent Heat for Low-melting Metal PCMs

摘要:

为根据实际需求 “设计”金属相变材料，建立了低熔点合金的熔点和相变潜热的计算模型。通过分析二元共晶合金相变中熵及焓等状态量的变化特点推导出熔点和相变潜热预测模型，并将预测模型向多元合金进行了推广。利用预测模型计算得到15种低熔点合金的熔点和相变潜热的计算值，通过与DSC的测试结果进行比较并且对误差进行分析发现：熔点和相变潜热的计算值与测量值具有较好的一致性。并且得出一个配制金属相变材料的原则：若想得到相变潜热较高的合金，则应该选取相变潜热高的元素作为合金组元，并且提高该元素的含量。该预测模型的优点是仅依靠合金元素本身的物理参数即可较准确地预测合金的熔点和相变潜热，从而避免了大量的实验。

Abstract:

In this paper, models are presented for predicting the melting point and latent hear of low-melting alloys to facilitate the design of PCMs. Based on the characteristics of entropy and enthalpy during the transition of material phase, the prediction model of melting point and latent heat for eutectic binary system are established at first, and then the models are extended into multicomponent system. Calculated melting point and latent heat of 15 selected low-melting alloys are compared with measurement results using DSC, which shows a good agreement between the prediction and the experimental data. A criterion for preparation of metallic PCMs is also proposed that in order to obtain higher latent heat alloy, an element with higher latent heat should be selected as component of alloy, and the mole fraction of the element should be increased. The advantage of the models proposed is that the melting point and latent heat of certain PCM can be predicted mathematically, avoiding the many experiments needed in conventional ways.