Abstract: The shape of TiC can be octahedral, facet or/and non-facet dendrite in as-cast Titanium alloys. The growth
element and growth habit of TiC₆ in titanium alloys were analyzed with the theory of coordination polyhedron through directionally solidified
samples. The results indicate that the growth elements of TiC are TiC₆ with six coordinations. During the stacking of TiC₆ growth element, the
growth rates of families {100} and {111} are different, which may easily result in potential nuclei of octahedral TiC surrounded by {111}. During
the growing of TiC in the melt, the undercooling and composition at different part of the crystal’s surface vary significantly. Some quadratic dendrites
may appear in the direction of <100> and are characterized by facet growth resulting in facet dendritic TiC finally. If a large amount of
defects such as screw dislocation are foed on the slowly growing surface of TiC during the growth, the facet will disappear and non-facet dendritic
TiC will fo.

Key words: titanium alloy, TiC, growth element, growth habit