镍基高温合金单晶叶片凝固组织模拟  

Solidification Microstructure Simulation of Ni-base Single Crystal Blade

作　　者：李海松[1,2] 李林蓄 曾洪[1,2] 杨照宏 杨功显[1,2] Li Haisong;Li Linxu;Zeng Hong;Yang Zhaohong;Yang Gongxian(Dongfang Turbine Co.,Ltd.;State Key Laboratory of Long-life High Temperature Materials)

机构地区：[1]东方电气集团东方汽轮机有限公司 [2]长寿命高温材料国家重点实验室

出　　处：《特种铸造及有色合金》2018年第12期1312-1316,共5页Special Casting & Nonferrous Alloys

摘　　要：采用CAF模型对DZ445高温合金单晶叶片定向凝固组织进行了数值模拟,在CAF模型中分别采用高斯分布连续形核模型和扩展KGT模型描述晶粒形核和枝晶尖端生长速率,研究了组模方式和抽拉速率对叶片凝固组织的影响。结果表明,倾斜组模可消除缘板杂晶,但可能会引入新的杂晶;抽拉速率越小越易形成单晶,抽拉速率越大越易形成杂晶;分段变速抽拉可消除缘板杂晶,但变速的位置距缘板应保持一定距离,此距离随叶片尺寸和抽拉速率而发生变化。A three dimensional cellular automaton-finite element model was developed to predict the so- lidification grain structures of DZ445 superalloy Ni-based single crystal,in which Gaussian distribution continuous nucleation model was adopted to describe the nucleation and the KGT model was extended to multi-component alloys to account for the growth kinetics of dendrite tip.Effects of slope angle and withdrawal rate on directional solidified microstructure evolution were investigated.The results reveal that slope wax-pattern can eliminate the stray grain formed at platform,however probably form new stray grain at other location.With increasing in the withdrawal rate,more stray grains are formed at platform.However sectional variable withdraw rate can eliminate the platform stray grain.Inaddition, the distance from airfoil where start change withdraw rate to platform should be keep a certain number, and which is determined through the size of blade and withdraw rate.

关 键 词：CAFE 镍基高温合金 单晶叶片 凝固组织 

分 类 号：TG249.5[机械工程—精密仪器及机械] TG146.13[金属学及工艺—铸造]