J Mater Sci Technol ›› 1990, Vol. 6 ›› Issue (3): 167-172.

• Articles • Previous Articles     Next Articles

Effect of Solidification Interface Morphologies on Microstructures of a Ni-base Superalloy

SHI Zhengxing LI Jianping FU Hengzhi Northwestern Polytechnical University,Xi'an,710032,China.Xi'an Institute of Technology,Xi'an,710032,China.   

  • Received:1990-05-28 Revised:1990-05-28 Online:1990-05-28 Published:2009-10-10

Abstract: A cast Ni-base superalloy K5 was directionally solidified and various solidification in- terfaces including plane front,cellular, cellular-dendritic and dendritic were obtained in a wider range of G/R ratio by using improved high withdrawal device and liquid metal cooling experi- mental sets.The precipitation pattern of some prin- cipal phases of the alloy and correlation of the vari- ous interfaces with microstructure were studied sys- tematically.It was indicated that the morphology of solidification interface of superalloy K5 varied with G/R ratio and that the solidification interface morphologies have a considerable effect on the fea- tures of phases both precipitated during solidification and post-solidification.Plane front and cellular directional solidification of superalloy K5 lead to a substantial decrease of MC carbide and elimination of γ-γ'eutectic,but make needle-shape M_6C carbide precipitate easily during ageing treatment.The finer dendritic structures solidified under the condition of higher cooling rate have less dendritic segregation and ideal microstructure.

Key words: Ni-base superalloy, solidification, microstructure