The enhanced formation of the C54-TiSi2 phase by the addition of small amounts of refractory metal (Tm = Mo, Ta, Nb,..) has often been ascribed to a template mechanism from the C40 TixRm1−xSi2 or the (Ti,Rm)5Si3 phase. Due to lattice matching conditions, the presence of either of these phases is thought to lower the interface energies with certain orientations of the C54-TiSi2 grain and, thereby, possibly lower the nucleation barrier of the C54-TiSi2 phase. These proposed template mechanisms are specifically tested in the present work through a study of the nucleation of TiSi2 phase(s) in contact with a pre-existing C40 Ti0.4Mo0.6Si2 or Ti5Si3 layer. No identifiable enhancement in the C54-TiSi2 nucleation was observed which could be attributed to templates. Instead, the nucleation temperature of the C54-TiSi2 phase appeared to be correlated with the grain size of the C49-TiSi2 layer, independent of whether Rm was present. These results are suggestive that the primary mechanism for the enhanced formation of the C54 phase by refractory metals is a reduction in the grain size of the C49 TiSi2phase, likely due to altered kinetics.