Electron Diffraction Structure Analysis of Two Kinds of New Iron Carbides with High Carbon Content

KCI single crystal fragments are obtained in natural cleavage forms by rapid cooling of the melt. Several features of the various macroscopic defects in the above fragments are summarized as follows: (i) The step lines (stepwise striations) can be observed on the cleaved surface. The propagation and the formation of these lines are discussed in relation to different macroscopic defects in the crystal. (ii) Micro-grain structures were observed in the subgrain of the crystal. The crystal was compressed and the migration or deformation of the micro-grain was observed even under a very weak compression below the yielding stress. (iii) The distribution of the crystal edge d depends on the cooling velocity v as dt 1/v 2 , in the crucibles are of some systematic one. (iv) The distribution of impurity concentration does not fit to the simple segregation rule, but some modification in the crystal growth direction might explain these results. In particular, it is known that the impurity density is low locally in the region in which the crystal grows in a high growth rate direction of the crystal. Further the macroscopic features are proved to be related to the microscopic ones.