High-resolution electron microscopy studies on coherent plate precipitates and nanocrystals formed by low-temperature heat treatments of amorphous Ti-rich Ti-Ni thin films

Abstract Further high-resolution electron microscopy studies have been performed on coherent thin non-equilibrium precipitates and unique nanocrystals with an identical orientation, which are produced from sputter-deposited amorphous Ti-48.2 at.° Ni thin films by heat treatments near or below the crystallization temperature Tc . Abundant evidence is provided for the previously proposed mechanisms for formation of the subnanometric precipitates near Tc and the nanocrystals below Tc ; it is as follows. For heat treatment below Tc , firstly a thin plate precipitate with the {100} habit plane, which has a bct lattice with its tetragonal axis perpendicular to the habit plane, is frequently observed at the crystal-amorphous interface, secondly the bct precipitates constituting the boundaries between nanocrystals are arranged in such a way that they can truncate an approximately spherical nanocrystal, while keeping the coherency with the B2 matrix at the {100} habit plane, thirdly enrichment of Ti atoms is detec...