Al—Si合金凝固相变热的Fourier算法

应用Fourier有源热传导理论，使用装有两支热电偶的分析样环，研究了铝合金凝固相变热的Fourier算法及其计算机辅助分析系统。测量了含Si量分别为6.34%、7.68%和8.46%铝合金的凝固相变热。计算结果分别为407、411和429kJ/kg。与差热分析法比较，最大误差为5%，其计算精度远高于Newton算法。实验结果证明，使用凝固始点和终点的热扩散系数αs、αe和Newton迭代法来计算凝固区间的“零”曲线具有更好的精度，所确定的“零”曲线更接近凝固相变的自然过程。说明建立在这种算法上的合金凝固质量计算机辅助冷却曲线分析系统，可广泛地用于材料加工过程的信息和参数计算。

Fourier Arithmetic Study of Al-Si Alloy Solidification Latent Heat

Based on Fourier's heat conduction theory and by use of sample cup instrumented with two thermocouples, the Fourier arithmetic for calculating Al-Si alloy solidification latent heat and its computer-aided analysis system were developed. Solidification latent heat of the three kinds of Al-Si alloy contained 6.34％Si, 7.68％Si and 8.46％Si was measured on this system, and the calculation results were 407, 411 and 429 kJ/kg respectively. Compared with the difference thermal analysis value, the precision of calculating solidification latent heat is much higher than that of Newton arithmetic. The maximum error value is 5％. The experimental results show that the Fourier zero curve between solidification start point and solidification end point reflects the nature process of Al-Si alloy solidification, its shape is neither logarithm curve nor linearity curve, and therefore the zero curve calculating with heat diffuse coefficient of the solidification start point αs and end point αe and Newton's iterative method has very high precision. The computer-aided cooling curve analysis system of alloy developed on the Fourier's method can be widely used for calculation of quality information and parameter during alloy solidification.