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Analytical TEM Study of Nanophase Precipitation in Nial Alloys
Published online by Cambridge University Press: 02 July 2020
Extract
Alloying additions have been found to enhance the mechanical properties of NiAl through solid solution strengthening and the precipitation of 2°d phases. The precipitation of fine, homogeneously nucleated ß' (Ni2Al (Ti,Hf)) has been observed and characterized by dark-field imaging and electron diffraction. The exact composition of these and other precipitates, however, remains unknown. In this study, the composition of the fine ( <20 nm) ß’ precipitates in NiAl alloys is measured and compared to that of well-developed ß’ plates in the matrix.
Two directionally solidified NiAl single-crystal alloys, NiAl-3Ti-0.5Hf and NiAl-7Ti (at.%) were grown by a Bridgeman technique using high purity alumina crucibles. Both ingots were homogenized for 32 h at 1644 K. In addition, the NiAl-3Ti-0.5Hf sample was aged at 1255 K for 6 h and furnace cooled. Samples for transmission electron microscopy were prepared from 3 mm diameter cylinders electro-discharge machined from the heat-treated ingots.
- Type
- Analytical Electron Microscopy
- Information
- Microscopy and Microanalysis , Volume 3 , Issue S2: Proceedings: Microscopy & Microanalysis '97, Microscopy Society of America 55th Annual Meeting, Microbeam Analysis Society 31st Annual Meeting, Histochemical Society 48th Annual Meeting, Cleveland, Ohio, August 10-14, 1997 , August 1997 , pp. 1007 - 1008
- Copyright
- Copyright © Microscopy Society of America 1997
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