定向凝固界面速率对机械牵引速率的响应  

Response of Interface Velocity to the Traction Rate during Directional Solidification

作　　者：蔡英文[1,2] 俞露[1,2] 许振明 李建国[1,2] 傅恒志 

机构地区：[1]西安交通大学机械学院铸造研究所 [2]西北工业大学凝固技术国家重点实验室

出　　处：《人工晶体学报》1998年第2期141-145,共5页Journal of Synthetic Crystals

基　　金：国家自然科学基金;国家教委博士点专项基金

摘　　要：通过传热分析，给出了定向凝固过程中界面速率对机械牵引速率的响应函数，指出在低速凝固条件下，界面速率可以视为与牵引速率相等；而在高速凝固时界面速率相对于牵引速率存在滞后现象。两个速率保持同步的上限值受到冷却环境、试样尺寸、合金热物理性质等的影响。液相前沿的温度梯度与冷却介质、加热方式以及合金体系有关。在此基础上，分析了实现稳定的亚快速定向凝固的条件。By analysis of heat transfer during directional solidification,it is given the response function of solid liquid interface velocity to the traction rate,which can be applied under the condition of local equilibrium.The result indicates that the solid liquid interface moves synchronously with the traction rate at low speed,but lags behind at high traction rate.The upper limit of the synchronous velocity depends on the cooling environment,thermal properties of the solidifying material and specimen size. The temperature gradient ahead of the solid liquid interface can be effectively increased by intensified cooling,forced heating and adoption of alloy system with high melting point,low latent heat and large thermal conductivity.On the basis of the above analysis,necessary conditions for steady nearrapid directional solidification are put forwatd.

关 键 词：定向凝固 界面速率 牵引速率 固液界面 机械牵引 

分 类 号：TG111.4[金属学及工艺—物理冶金] TG244.3[金属学及工艺—金属学]