Effect of Samarium on the Properties of Hot-Extruded Mg–Y–Gd–Zr Alloys

Abstract

The effect of such an additional promising alloying element as samarium on hot-extruded Mg–Y–Gd–Zr alloys is investigated. The microstructure, kinetics of aging during the decomposition of a supersaturated Mg solid solution, and the mechanical properties of the alloys are studied. The differences of the recrystallization processes that occur in hot-extruded alloys with various contents of samarium (0, 1.7, 2.5%) are demonstrated. After hot extrusion, Mg–Y–Gd–Zr and Mg–Y–Gd–Sm–Zr alloys are additionally hardened during aging due to the decomposition of a supersaturated Mg solid solution. At the same time, samarium changes the nature of this hardening. The alloys with samarium are hardened faster, and the maximum hardness is achieved with shorter aging exposures. The mechanical properties of hot-extruded Mg–Y–Gd–Zr alloys with samarium addition are determined at room and elevated up to 300 °C temperatures. The efficiency and expediency of using samarium both as a separate alloying element and as a partial replacement of more expensive rare-earth elements in alloys with yttrium and gadolinium are shown.

Keywords

• magnesium alloys
• rare earth metals
• hot deformation
• microstructure
• aging
• precipitation