Phase equilibria of the Tb-Fe-B system at 1000, 900 and 800 °C

Phase equilibria of the Tb-Fe-B system were investigated at 1000, 900 and 800 degrees C using X-ray diffraction (XRD) and electron probe microanalysis (EPMA) on annealed alloys with a B content <= 50 at.%. Isothermal sections at 1000, 900 and 800 degrees C were then proposed, revealing the similar phase equilibria except for the phase regions containing liquid, which originates from the binary Fe-Tb system at 900 and 1000 degrees C. Five ternary compounds of Tb2Fe14B, TbFe4B4, Tb5Fe2B6, Tb3FeB7 and TbFeB4 were observed to be stoichiometric and the solubilities of Tb in Fe-B, Fe in Tb-B and B in Tb-Fe binary phases were measured to be negligible. Additionally, the ternary compound TbFe2B2 was not detected in this work.