The magnetic properties and structure of as-cast hypo- and hypereutect
ic Fe-Nd alloys processed in hydrogen have been investigated. When pro
cessed for a short time, both Fe17Nd2 phase and metastable Al phase ab
sorb hydrogen with an increase of their Curie temperatures. Long-term
hydrogenation at 600-degrees-C results in a decomposition of all the h
ydrides except NdH2-epsilon, which as well as alpha-Fe is stable under
these conditions. It has been shown that an fcc. phase encountered in
as-cast hypereutectic Fe-Nd alloys is a neodymium-based hydride whose
lattice parameter is changed in a complicated manner when the alloy i
s heat treated. Multistage decomposition of A1 phase in the hydrogenat
ed Fe14Nd86 alloy leads finally to the formation of very fine and appa
rently nonequiaxed precipitates of alpha-Fe in the NdH2-epsilon matrix
resulting in a coercivity of 0.4 kOe.