Pseudo-binary systems involving rare earth laves phases

Abstract

The phase relations in a number of pseudo-binary systems involving rare earth Laves phases have been determined. Complete series of cubic solid-solutions occur in the DyMn 2HoMn 2, HoMn 2HoFe 2, DyMn 2DyFe 2, HoMn 2HoAl 2, TbMn 2TbAl 2 and DyMn 2DyAl 2 pseudobinary systems. Deviations from linearity in the lattice constants with composition occur in all these systems. Complete series of cubic solid-solutions also exist in the GdAl 2ErAl 2, GdAl 2PrAl 2, GdAl 2NdAl 2, GdAl 2DyAl 2, TbAl 2NdAl 2 and TbAl 2DyAl 2 systems. For these systems, no deviation from linearity occurs in the lattice constants. For the DyFe 2DyAl 2 and DyCo 2DyAl 2 systems, two new ternary phases, DyFeAl and DyCoAl, form and have the MgZn 2 structure. Their structures were determined from X-ray powder data only. The electronic state giving rise to the formation of these ternary phases is discussed qualitatively. For the DyMn 2TmMn 2 system, the range of composition in which the cubic MgCu 2 and hexagonal MgZn 2 structures exist are reported. No complete series of solid solutions or intermediate phases formed in the DyNi 2DyAl 2 system.