抽拉速率对定向凝固DZ4125合金温度场及晶粒竞争生长的影响  

Effect of withdrawal rates on temperature field and grain competitive growth of directionally solidified DZ4125 alloy

作　　者：刘国怀[1] 张相龙 耿小奇 徐莽 王晔[2] 王昭东[1] 郭景杰[3] LIU Guohuai;ZHANG Xianglong;GENG Xiaoqi;XU Mang;WANG Ye;WANG Zhaodong;GUO Jingjie(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;School of Material Science and Chemical Engineering,Harbin University of Science and Technology,Harbin 150080,China;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,沈阳110819 [2]哈尔滨理工大学材料科学与化学工程学院,哈尔滨150080 [3]哈尔滨工业大学材料科学与工程学院,哈尔滨150001

出　　处：《航空材料学报》2023年第2期17-24,共8页Journal of Aeronautical Materials

基　　金：国家自然科学基金(52071065);中央高校基本科研业务费(N2007007)。

摘　　要：为探究定向凝固DZ4125柱晶高温合金中温度场分布情况,并研究不同抽拉速率对温度梯度及糊状区变化的影响规律,利用ProCAST软件对抽拉速率分别为3、5、7 mm/min的定向凝固过程进行模拟。结果表明:当试棒位于保温区时,等温线呈外侧低内侧高的倾斜分布,当试棒位于冷却区时,等温线呈外侧高内侧低的倾斜分布;随着抽拉速率的增加,温度梯度逐渐减小;糊状区形状取决于抽拉速率和距水冷盘的距离,当抽拉速率为5 mm/min时,凝固前沿水平状保持的时间最长;在此基础上,对定向凝固试棒进行精铸实验,并研究3mm/min和7 mm/min下试棒液相线形状与晶粒结构之间的关系,发现液相线呈凹形和凸形时,晶粒分别向试棒中心和表面方向生长,水平的液相线能促进晶粒沿试棒轴线方向生长。In order to investigate the distribution of temperature field in directionally solidified DZ4125 columnar superalloy,and to study the effects of different withdrawl rates on the changes of temperature gradient and mushy zone,the directional solidification processes with withdrawal rates of 3,5 and 7 mm/min were simulated by ProCAST software.The results show that when the test rod is located in the heating zone,the isotherm is inclined distribution with low outside and high inside.And when the test rod is located in the cooling zone,the isotherm is inclined distribution with high outside and low inside.With the increase of withdrawal rate,the temperature gradient decreases gradually.The shape of the mushy zone depends on the withdrawal rate and the distance from the water-cooled plate.When the withdrawl rate is 5 mm/min,the horizontal state of the solidification front is maintained for a longest time.On this basis,the precision casting experiment of directional solidification test rod is carried out,and the relationship between the shape of liquidus and grain structure is found for castings withdrawn at 3 and 7 mm/min.It is found that when the liquidus is concave and convex,the grain grows towards the center and the surface of the test rod,and the horizontal liquidus can promote the grain growth along the axis of the test rod.

关 键 词：定向凝固 PROCAST 温度梯度 糊状区 液相线 晶粒生长 

分 类 号：TG132.32[一般工业技术—材料科学与工程]