金属及合金熔点热物性动态测试新方法研究

Investigation on the New Methods for Dynamic Measurement of Thermophysical Properties of Metals and Alloys at the Melting Point

利用物质熔化与凝固过程中导热逆(或反)问题原理,在建立了相界面移动与两相热物理性质关系的基础上,提出了一种新颖的热物性动态测试方法,即由相变速率动态测试热物性参数。由于是对熔点高的金属进行测试,故不能采用解析求解,而是运用数值求解;并用铅、锌、铝等已知热物性的金属对此方法进行了评定,测试结果与参照值误差不超过3%;还对相变导热系数未知的铅锑、铅锡、铋锡、铝硅、铝铜5种共晶合金进行了测试,其结果具有较高的参考价值。该方法的优点在于测试过程中所求热物性参数与相界面位置是由精确的传热方程所约束,故测量较简便,结果准确、可靠、误差小,并可测得多个热物性数据。

Based on the principle of inverse heat conduction, the moving boundary is related to the thermophysical properties of two phases, a new method for determinating thermophysical properties of two phases near the melting point has been developed. For the suitable to the matal with high melting point, the numerical analysis is adopted. It is a combination of experiment and mathematical simulation and it uses the propagation of the liquid-solid interface as an indication of the heat flux. Comparing the measured data of Pb,Zn and Al with reference value, the reliability of the new method is experimentally comfirmed. Numerical simulation on these metals shows that results are quite reasonable. Five eutectic alloys (Pb-Sb,Pb-Sn,Bi-Sn,Al-Si,Al-Cu) are made up and their conductivities near their phase transformation temperature have been measured. Advantages of this method are as follows: due to the relation between thermophysical properties and the phase change boundary is restricted by the strict differential equations, so that the results are reliable; the structure of crystal and physical properties of samples do not vary during the process of measurement and various thermophysical data can been measured simultaneously.