定向凝固过程中单晶合金枝晶生长的研究进展

Study on Dendritic Growth in Single Crystal Alloys During Directional Solidification

摘要:

随着定向凝固技术与工艺的不断发展，工程技术人员对枝晶生长的控制也越来越精准。为使枝晶生长朝着人们设定的方向发展，进而获得理想的组织结构，凝固过程的控制成为关键因素。定向凝固技术制备的合金虽能提高其综合力学性能，但受到枝晶生长等多方因素影响，因此有必要对枝晶生长方面的研究工作进行评述。综述了定向凝固工艺参数、合金成分和晶体取向对枝晶生长的影响，尤其是对一次枝晶间距的影响。通过建立物理模型来模拟枝晶的生长过程，一方面来验证理论模型的有效性，另一方面对干扰因素进行预测和控制。此外，论文还分析与讨论了一次枝晶间距的极端范围与边界条件。最后，对影响定向凝固控制枝晶生长的因素进行了总结和展望。

Abstract:

With the continuous development of directional solidification technology and the continuous updating and optimization of solidification process， the control of dendritic growth has become more and more precise. In order to control the dendritic growth to the desired direction and obtain the ideal structure， it is the key to control the solidification process. The high-quality alloys produced by directional solidification technology can improve their comprehensive mechanical properties， but dendrite growth is affected by many factors. Therefore， the research on dendrite growth is summarized. The effects of directional solidification process parameters， alloy compositions and crystal orientations on dendritic growth， especially on the primary dendrite spacing， are reviewed. By establishing a model to simulate the dendrite growth process， on the one hand， the validity of the theoretical model is verified， and on the other hand， the interference factors can be predicted and controlled. In addition， the allowable range of the primary dendrite spacing is also analyzed， and its upper and lower limits are discussed. Through the study of dendritic growth， the theoretical basis for the research and development of single crystal alloys is provided.