Structure and properties of rapidly solidified Mg-based MgPr alloys

Mg-based alloys containing 1 to 15wt% Pr were rapid-quenched by melt-spinning. Lattice parameters of αMg, microstructure and microhardness of as-quenched ribbons were studied using optical microscope, XRD and TEM. Lattice parameters a and c of αMg solid solution were increased with increasing alloy content up to 5 to 10wt% Pr indicating that the solid solubility of Pr in αMg could be extended to 5-10wt% Pr by melt-spinning. Microhardness of the as-spun ribbons was also increased from 53 to 167 kg/mm² with increasing alloy content from 1 to 15 wt% Pr. TEM study showed that grained αMg equiaxed in cross section with few fine second phase along grain boundaries formed in Mg-1 wt%Pr ribbon while primary αMg with coarser second phase plus degenerated eutectic formed in Mg-15wt%Pr ribbon. The solid solubility extension of Pr in αMg and possible significant of the result for development of microcrystalline light-weight Mg-based alloys are discussed.