Orientation relationships of carlsbergite in schreibersite and kamacite in the north Chile iron meteorite

摘要

The crystallographic orientation of carlsbergite (CrN) in the north Chile meteorite (hexahedrite) was investigated using electron backscatter diffraction and transmission electron microscopy. These studies examined the CrN crystals in the rhabdites (idiomorphic schreibersite) and in kamacite. It was found that the CrN crystals embedded in rhabdite show a number of different orientation relationships with the host crystals. These orientations can be explained based on the lattice dimensions of both coexisting crystalline materials. It was also found that both carlsbergite and kamacite are characterized by a high dislocation density (>= 10~9 cm~(-2)) while rhabdite is free of dislocations. It is supposed that in spite of the deformed metallic matrix, a general connection between the orientation relation of all the phases involved exists.