Effect of cooling rates on dendrite spacings of directionally solidified DZ125 alloy under high thermal gradient

作     者：ZHANG Weiguo LIU Lin ZHAO Xinbao HUANG Taiwen YU Zhuhuan QU Min FU Hengzhi ZHANG Weiguo, LIU Lin, ZHAO Xinbao, HUANG Taiwen, YU Zhuhuan, QU Min, and FU Hengzhi State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China

作者机构：State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2009年第28卷第6期

页      面：633-638页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：supported by the National Natural Science Foundation of China (Nos.50771081,50827102) the National Basic Research Program of China (No.2006CB605202) 

主　　题：directional solidification superalloy thermal gradient cooling rate dendrite arm spacing 

摘      要：The dendrite morphologies and spacings of directionally solidified DZ125 superalloy were investigated under high thermal gradient about 500 K/cm. The results reveal that, with increasing cooling rate, both the spacings of primary and secondary dendrite arms decrease, and the dendrite morphologies transit from coarse to superfme dendrite. The secondary dendrite arms trend to be refined and be well developed, and the tertiary dendrite will occur. The predictions of the Kurz/Fisher model and the Hunt/Lu model accord basically with the experimental data for primary dendrite arm spacing. The regression equation of the primary dendrite arm spacings 21 and the cooling rate Vc is λ1 = 0.013 Vc^-0.32. The regression equation of the secondary dendrite arm spacing λ2 and the cooling rate Vc is λ2 = 0.00258 Vc^-0.31, which gives good agreement with the Feurer/Wunderlin model.