| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1600952 | Intermetallics | 2011 | 8 Pages |
Pseudobinary NiAl–W section in the range 0.7–1.8 at% was characterised regarding solidification microstructure and constitution. The existence of eutectic reaction was confirmed and occurs at temperature of 1664 ± 2 °C and the composition of 1.5 at% W. As-cast microstructures indicated that the NiAl–W system is an anomalous eutectic with skewed coupled zone and that the NiAl phase is a preferential phase for eutectic nucleation. Directionally solidified alloy containing 1.5 at% W exhibited entirely eutectic structure characterised by eutectic cells with the average value of 500 μm, interfibre spacing 3.5 μm, fibre diameter 300 nm, and volume fraction of the W phase 1.4%. The solubility of W in the intermetallic phase is <0.04 at% and the solubility of Ni and Al in the W phase is negligible. Crystallographic orientation between the constituent phases was established to be cube on cube. Based on the results obtained by DTA, microstructural and compositional analysis, a new isoplethal section NiAl–W of the ternary Al–Ni–W system has been proposed.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Eutectic reaction in psuedobinary NiAl–W system occurs at 1664 ± 12°C and 1.5 at% and W. ► It is anomalous eutectic with skewed coupled zone. ► Preferential phase for eutectic nucleation is NiAl and both phases are non-facted. ► Size of eutectic cell is 500 μm, fibre diameter 300 nm and fibre spacing 3.5 μm. ► Constituent phases show cube on cube orientation relationship.
