HOLZ rings in EBSD patterns of the UFeB₄ compound: association with a random distribution of planar defects.

The UFeB₄ phase present in different alloys of the B-Fe-U system was studied by powder X-ray diffraction (PXRD) and scanning electron microscopy complemented with energy-dispersive spectroscopy and electron backscattered diffraction (EBSD). The PXRD data showed that the ternary compound crystallized adopting essentially the YCrB₄-type structure. However, microstructural observations revealed that under high undercooling conditions the UFeB₄ phase exhibits a random distribution of defects parallel to, which are consistently associated with intense higher-order Laue zone rings in EBSD patterns. Indexation of the EBSD patterns showed that the defective structure is compatible with an intergrowth of YCrB₄- and ThMoB₄-type layers according to the (010)(YCrB₄)//(110)(ThMoB₄) and [001]YCrB₄//[001](ThMoB₄) orientation relation previously reported for an analogous compound. Magnetic studies indicated that the annealed UFeB₄ compound has a paramagnetic behavior in the 2-300 K temperature range.