Microstructural study on the C49-to-C54 phase transformation in TiSi2 formed from preamorphization implantation

Microstructural characteristics of C49–TiSi2 in narrow lines have been investigated by transmission electron microscopy. The C49–TiSi2 formed by a preamorphization treatment exhibits small grain size and heavily faulted structures. C54 grains are also observed sporadically in the C49 matrix in spite of relatively low temperature range. Moreover, defects circularly distribute around a less-defective region in the vicinity of the C54 grains. The C49 grains in these regions are well aligned with identical crystallographic orientations. These results indicate two-dimensional growth of C49–TiSi2, and the circular defects are introduced by internal stress associated with the growth process. Also the internal stress is considered to enhance the heterogeneous C54 nucleation.