在压铸过程中，铸件-铸型界面换热行为决定着铸件的凝固过程，因而直接影响着铸件内部组织和缺陷的形成以及最终的力学性能等。界面换热系数是表征铸件-铸型界面换热行为的重要参数，准确求解并应用铸件-铸型界面换热系数是研究工作者广泛关注的课题，论文研究工作具有重要的理论及实际意义。论文深入研究了热传导反算法，发现采用傅立叶数#可以很好地表征热传导反算过程，且该参数必须满足#才能保证反算过程的稳定性以及准确性。以此为基础，确定了适合压铸的反算参数。基于确定的压铸反算参数，设计了“阶梯”铸件和测温单元，系统进行了压铸实验，准确地测量了不同工艺条件下铸型内部的温度曲线。求解了压铸过程铸件-铸型界面换热系数，该值可以分为初始升高、高值维持、快速下降以及低值保持四个阶段。铸件壁厚与合金材料对换热系数的影响主要表现在高值阶段所能达到的数值以及持续的时间上，铸件壁厚对换热系数的影响还表现在快速下降阶段换热系数的下降速率上。通过数据拟合，在快速下降阶段，换热系数h和铸件凝固分数fs以及凝固速率v之间存在以下函数关系：#，#。对于压铸薄壁件来说，v和h之间近似为线性变化关系。工艺参数对换热系数的影响主要表现在峰值上，且铸型的初始表面温度TDI对换热系数峰值hmax有决定性影响，采用回归分析发现二者具有以下函数关系：#。高速速度的提升只对铸件较薄处的换热系数峰值有增加作用，铸造压力的影响只在AM50合金铸件较厚处表现地比较明显，其他工艺参数对换热系数峰值的影响不大。根据换热系数和固相分数的关系建立了边界设定模型，并用于实际压铸件温度场的求解和热平衡分析中。研究发现，该模型可以准确地表征实际凝固过程铸件-铸型边界条件，特别的是该模型可以准确预测凝固初期铸件和铸型温度的快速变化阶段，从而实现对压铸凝固过程的准确模拟。

During high pressure die casting (HPDC) process, the solidification of castings is highly dependent on the heat transfer behavior at the metal-die interface, and it is believed that such heat transfer behavior could directly influence the formation of the microstructure and defects and the final mechanical properties of the castings. Interfacial heat transfer coefficient (IHTC) is a key parameter charactering the heat transfer behavior at the metal-die interface, and the determination and application of this coefficient is becoming a key issue to the researchers nowadays. Therefore, it is of important theoretical and practical significance to study the metal-die interfacial heat transfer coefficient in a HPDC process. This dissertation systematically studied the inverse thermal estimation method and found that the inverse determination procedure can be totally characterized by the Fourier number,#, and its value has to follow a criteria of # to maintain the stability and accuracy of the inverse calculation. The Fourier number and the criteria were used to determine the parameters for the inverse modeling during the HPDC process.Based on the evaluated parameters for the inverse modeling, a “step shape” casting and temperature measurement unit were designed. Systematical die-casting experiments were conducted and temperature profiles were measured precisely under different operation conditions. The IHTCs in HPDC were successfully determined by the inverse method and it was found that the IHTCs can be divided into four stages, namely the initial increasing stage, the high value maintaining stage, the fast decreasing stage and the low value maintaining stage. The casting thickness and alloy composition mainly influence the IHTCs on the value and duration during the high value maintaining stage. Another influence of the casting thickness on the IHTC is on the changing rate during the fast decreasing stage. Through data correlation, it was found that during the fast decreasing stage, the IHTC (h) changes as a function of the solid fraction (fs) in a manner of # and the solidification rate (v) changes as a function of the IHTC (h) in a manner of #, respectively. For the thinner castings, the solidification rate changes approximately linearly with the IHTC. Influence of the processing parameters on the IHTC is mainly on the peak value. It was found that the initial die surface temperature (TDI) has the dominant influence on the IHTC peak value (hmax) out of all the processing parameters. Through correlation analysis, the following relationship was found to have the best fit: #. Increase of the fast shot velocity only increases the IHTC peak values at the thinner parts of the casting. Influence of the casting pressure on the IHTC peak value was found to be only prominent at thicker part of the casting for the AM50 alloy. Other processing parameters have little influence on the IHTCs.Based on the relationship between the IHTC and the solid fraction, a boundary-condition model was developed and applied to model the thermal field and thermal equilibrium of practical die casting process. Results showed that the proposed model could precisely simulate the boundary condition at the metal-die interface during the solidification process. Particularly, the proposed model could accurately demonstrate the fast change of the temperature of both casting and die at the initial stage of the solidification process and therefore could be used practically to predict the actual solidification status of the casting in HPDC process.