Influences of processing parameters on microstructure during investment casting of nickel-base single crystal superalloy DD3  

作　　者：Gao Sifeng Liu Lin Xu Yiku Yang Chubin Zhang Jun Fu Hengzhi 

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestern Polytechnic University,Xi'an 710072,China

出　　处：《China Foundry》2012年第2期159-164,共6页中国铸造（英文版）

基　　金：supported by the National Basic Research Program of China(Nos.2010CB631202 and 2011CB610406);the National Natural Science Foundation of China(Nos.50827102,51171151 and 50931004);the Aeronautical Science Foundation of China(No.2010ZE53048);the China Post-doctoral Science Foundation Funded Project(No.20100481361)

摘　　要：The effects of solidification variables on the as-cast microstructures of nickel-base single crystal superalloy DD3 have been investigated by using the modified Bridgman apparatus. The experiments were performed under a thermal gradient of approximately 45 K.cm-1 and at withdrawal rates ranging from 30 to 200 m.s-1. The experimental results show that the primary and secondary dendritic arm spacings （PDAS and SDAS） decrease when the withdrawal rate is increased. Compared with the theoretical models of PDAS, the results are in good agreement with Trivedi＇s model. The relationships of PDAS and SDAS with withdrawal rates can be described as ;λ1 = 649.7V-0.24±0.02 and λ2 = 281 V-0.32±0.03, respectively. In addition, the size of the λ2 phase significantly decreases with increasing withdrawal rate.The effects of solidification variables on the as-cast microstructures of nickel-base single crystal superalloy DD3 have been investigated by using the modified Bridgman apparatus.The experiments were performed under a thermal gradient of approximately 45 K·cm-1 and at withdrawal rates ranging from 30 to 200 m·s-1.The experimental results show that the primary and secondary dendritic arm spacings(PDAS and SDAS) decrease when the withdrawal rate is increased.Compared with the theoretical models of PDAS,the results are in good agreement with Trivedi's model.The relationships of PDAS and SDAS with withdrawal rates can be described as ? 1 =649.7V -0.24±0.02 and? 2 =281V -0.32±0.03 ,respectively.In addition,the size of theγ′phase significantly decreases with increasing withdrawal rate.

关 键 词：Ni-base superalloys directional solidification γ′phase dendritic spacing 

分 类 号：TG249.5[机械工程—精密仪器及机械]