Microstructure Evolution and Compression Properties of a Directionally Solidified Ni-24.8%Nb Hypereutectic Alloy

Abstract:

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At normal solidification conditions, in-situ composites of a Ni-24.8%Nb hypereutectic alloy can be produced at growth velocities below 5μm/s, with a thermal gradient of 180K/cm, and this low productivity remarkably restricts the application of this kind of in-situ composites. In this paper, we proposed an approach that employs an abrupt growth velocity to make the in-situ composites grow stably out of the coupled zone. In-situ composites of the Ni-24.8%Nb hypereutectic alloy were obtained at a growth velocity of 100μm/s and the productivity was greatly improved. This value is in the same order magnitude imposed on the single-crystal superalloys. The compression strengths were investigated on different microstructures involving the coupled eutectics and non-coupled eutectics. The results showed that the crack distribution and extension were mainly localized in primary Ni3Nb dendrites in the non-coupled eutectics, and that in-situ composites with the entirely coupled eutectics have improved mechanical properties and different deformation behaviors.

Info:

Periodical:

Materials Science Forum (Volumes 654-656)

Main Theme:

Edited by:

Jian-Feng Nie and Allan Morton

Pages:

1351-1354

DOI:

10.4028/www.scientific.net/MSF.654-656.1351

Citation:

S. M. Li et al., "Microstructure Evolution and Compression Properties of a Directionally Solidified Ni-24.8%Nb Hypereutectic Alloy", Materials Science Forum, Vols. 654-656, pp. 1351-1354, 2010

Online since:

June 2010

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Price:

$35.00

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