Ti-Al-Nb
Titanium aluminides have been investigated for many years because of potential applications as turbine blades, and most effort is now concentrated on g-TiAl with various alloying additions such as Nb which can provide higher yield stress, improved room temperature ductility, and enhanced oxidation resistance. In our studies within the Integrated Project IMPRESS, phase formation processes at high melt undercooling are revealed for selected ternary Ti-Al-Nb alloys with EML experiments. The growth velocities are analysed and metastable phase formation is evaluated from microstructures of droplets quenched at different melt undercooling levels.
Thermal history of undercooled Ti-45Al-10Nb and Ti-50Al-10Nb samples
Direct formation of gamma phase in Ti-50Al-10Nb
change of the solidification pathway
Retaining of the metastable alfa2 phase in Ti-45Al-10Nb samples
supression of the postsolidification transformation
- O. Shuleshova, T.G. Woodcock, H.-G. Lindenkreuz, R. Hermann, W. Loeser, B. Buechner
Metastable phase formation in TiAlNb undercooled melts, Acta Materialia 55 (2007) Nr. 2, S. 681-689 URL - W. Loeser, H.-G. Lindenkreuz, R. Hermann, O. Shuleshova, T.G. Woodcock
Recalescence behaviour of binary TiAl and ternary TiAlNb undercooled melts, Materials Science and Engineering A 413-414 (2005), S. 398-402 URL