Effect of Original Microstructure on the Hot Compression Behavior of Superalloy 718

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Hot compression tests at different temperatures and strain rates were performed on superalloy 718 annealed at 1100 °C for 30 min as well as 950 °C for 30 min in order to investigate the effect of the original microstructure on the hot deformation behavior. The results show that the δ phase precipitated on the grain boundaries of superalloy 718 prior to hot deformation leads to a decrease of the flow stress, which can be attributed to the drop of the matrix strength. The activation energy (Q) for hot deformation of the fine-grained material with δ phase on the grain boundaries is determined to be 381 kJ/mol, which is much lower than that of the coarse-grained material without δ phase (472 kJ/mol). It is suggested that the initial δ phase precipitated on the grain boundaries of the annealed material affect the thermal activation process of hot deformation for superalloy 718, resulting in the decrease of activation energy.

Info:

Periodical:

Key Engineering Materials (Volumes 353-358)

Edited by:

Yu Zhou, Shan-Tung Tu and Xishan Xie

Pages:

515-518

Citation:

Y. Wang et al., "Effect of Original Microstructure on the Hot Compression Behavior of Superalloy 718", Key Engineering Materials, Vols. 353-358, pp. 515-518, 2007

Online since:

September 2007

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Price:

$38.00

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