Materials Transactions Online

Materials Transactions, JIM, Vol.38 No.11 (1997) pp.1016-1021
© 1997 The Japan Institute of Metals

Effect of Solidification Rate on the Microstructure of a Ni-Base Superalloy

Xuebing Huang, Yun Zhang, Zhuangqi Hu,
Honghua Deng and Yulin Liu

Institute of Metal Research, Academia Sinica, Wenhua Road,
Shenyang 110015, P. R. China

The effect of solidification rate on the solidified structure, solute segregation and microstructures such as carbide, γ'/γ eutectic, γ' phase and dendrite arm spacing was experimentally investigated employing a method of partially directional solidification and subsequent quick quenching. Three types of the solidified structure were identified: cellular, cellular-dendritic and developed dendrite-type, and the width of a mushy zone was narrowed when solidification rate increased from 2.5 µm/s to 125 µm/s. The carbide morphologies were affected by both solidified structure and solidification rate, it formed into bar-type in the cellular structure, and Chinese script-type in the dendrite structure. The increase of solidification rate caused a lot of γ'/γ eutectic and the change of γ' phase from cubic into cubic-round. The dendrite arm spacing decreased and the segregation of Cr, Al, Co, Mo, Ti was alleviated with increasing solidification rate.

(Received March 17, 1997)

Keywords: superalloy, solidification, microstructure

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© 1997 The Japan Institute of Metals