THE MICROSTRUCTURAL CHARACTERIZATION OF ND-FE-B ALLOYS .2. MICROSTRUCTURAL INVESTIGATION OF CAST ND-FE-B MATERIALS

The microstructures and crystal structures of the Nd2Fe14B, the NdFe4B 4 and Nd-rich phases were investigated using TEM. Schematic Kikuchi ma ps of these three phases have been constructed. The structure factors and extinction distances were calculated using an in-house programme. The NdFe4B4 phase had an incommensurate tetragonal structure with the stacking faults in the Fe sublattice. The habit plane of the stacking faults was {110BAR}. The structure forbidden diffraction maxima which appeared in the TEM diffraction patterns could be attributed to double diffraction. The Nd-rich phase had a fcc (a = 0.52 nm) + complex fcc (a = 1.04 nm) structure.