Extension of solid solubility of yttrium and rare earth metals in magnesium by rapid solidification

Major decreases of the axial ratio c/a of magnesium were found for its extended solid solutions with La, Ce, Nd, Sm, Eu, Gd, Yb and yttrium made by rapid solidification. The axial ratio of 1.6066 +- 0.0006 found for Mg-26.0 wt.% Y is the lowest ever reported value of c/a for a magnesium alloy. Solid solubilities have been extended by factors ranging from 2 for Mg-Yb (at cooling rates around 10/sup 6/ Ks/sup -1/) to at least 100 for Mg-Eu (at above 10/sup 8/ Ks/sup -1/) compared with the corresponding equilibrium solid solubilities. With few exceptions, both the amounts of solid solubility extension observed and the change of the lattice parameters versus concentration correlate well with atomic size factors. The change in lattice parameter approaches 1.6X10/sup -2/ A/at.% with increasing size of solute atom in extended solid solution