Daniel Gosslar et al 2009 J. Phys.: Condens. Matter 21 464111 doi:10.1088/0953-8984/21/46/464111
Daniel Gosslar1, Christian Hartig1, Robert Günther1, Ulrike Hecht2 and Rüdiger Bormann1
Show affiliationsThe barrier to heterogeneous nucleation of the β(Ti) phase on TiB2 and other borides has been evaluated using the plane to plane matching model. The results are compared to the known nucleation of the α(Ti) phase on the β(Ti) phase. According to this comparison, the barrier to heterogeneous nucleation of the β(Ti) phase on TiB2 can be judged to be small. This is in agreement with inoculation experiments. The addition of a Ti–Al–TiB2 master composite to a β(Ti) solidifying TiAl based alloy leads to a significantly refined microstructure. Microsegregations enable us to attribute this refinement to refined equiaxed β(Ti) dendrites. However, model calculations based on the hemispherical cap model predict that the refinement via heterogeneous β(Ti) nucleation should be more potent. First calculations indicate that structural imperfections of TiB2 particles limit the nucleation site diameter. Thereby, the nucleation barrier is increased and the refinement is less pronounced.
68.70.+w Whiskers and dendrites (growth, structure, and nonelectronic properties)
Soft matter, liquids and polymers
Issue 46 (18 November 2009)
Received 22 April 2009
Published 27 October 2009
Daniel Gosslar et al 2009 J. Phys.: Condens. Matter 21 464111
Shihua Zhao et al 2009 J. Phys. D: Appl. Phys. 42 225106
Jiahua Shi et al 2007 Nanotechnology 18 365704
L Fehér and B G Pusztai 2008 J. Phys. A: Math. Theor. 41 194009
Piero Tartaglia 2009 J. Phys.: Condens. Matter 21 504109
Wenchao Yang et al 2008 Nanotechnology 19 255101
M Larouche et al 2009 J. Phys. A: Math. Theor. 42 485203
Jes K. Jørgensen et al. 2007 ApJ 659 479
John W. Keck et al. 2001 ApJ 563 301
Shardha Jogee et al. 2002 ApJ 575 156