The Microstructure and Mechanical Properties of Directionally Solidified NiAl-15Cr Alloy at Various Temperatures

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The microstructure and tensile mechanical properties of directionally Solidified NiAl-15Cr alloy at various temperatures have been investigated in this paper. The results reveal that the microstructure consists of dendritic β-NiAl phase, interdendritic γ/γ’, γ’ phase transient layer and α-Cr precipitation in β-NiAl phase. With the increase of temperature obvious Brittle-Ductile-Transition (BDT) behavior is observed and the BDT temperature (BDTT) is sensitive to initial strain rate. When the initial strain rate increases by two-order magnitude, the BDTT has an approximate 150K increase. In the temperature range of 1123-1373K, the alloy exhibits good tensile plasticity and poor strength comparing with the NiAl/Cr(Mo,Hf) alloy. Superplastic-like deformation behavior with large elongation (exceed 200%) is achieved at 1323K. The balance between strain hardening (by dislocation glide) and strain softening (dynamic recover and recrystallization) is responsible for the large tensile elongation of this alloy.

Info:

Periodical:

Materials Science Forum (Volumes 475-479)

Main Theme:

Edited by:

Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie

Pages:

2623-2626

DOI:

10.4028/www.scientific.net/MSF.475-479.2623

Citation:

G. Y. Zhang et al., "The Microstructure and Mechanical Properties of Directionally Solidified NiAl-15Cr Alloy at Various Temperatures", Materials Science Forum, Vols. 475-479, pp. 2623-2626, 2005

Online since:

January 2005

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$35.00

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