A T.E.M INVESTIGATION OF THE MECHANISM OF EARLYSTAGE: ORDERING IN THE INTERMETTALIC COMPOUND PT2FECU

The microstructuralfeatures ofthe early stage ofordering ofthe intermetallic compound pt2fecu have been examined using optical and transmission electron microscopy in conjunction with x-ray diffraction technique. it was [ound th at the compound has similar morphological alteration to that of fept in which the ordering cannot besuppressed by rapid quenching. the earlv stage of ordering transformation wa.s' initiated at temperatures above the critical value 0.1' 1178 °c, by a homogeneous nucleation of the intermediate short range ordered particles and ultra rapid directional-inducedheterogeneous growth (burst type). as the result ofthese combined mechanisms, twin -related ordered domains have been fonned which in turn minimize the strains produced by ordering reaction in polycrystalline material. the individual grain was divided lip by different sizes oftwin-related ordered domain bonded with {101} habit planes.