Effect of Sm and Ce content on microstructure and mechanical property of newly developed Mg-Sm-Ce-Mn based alloy

Abstract

In this work, the effect of Sm and Ce contents on mechanical property of Mg-Sm-Ce-Mn based alloy have been investigated, and it is found that both the strength and ductility increased continuously with the increase of solute contents. In the as-extruded Mg-1.6Sm-0.8Ce-0.4Mn alloy, a high strength-ductility synergy was obtained, with yield strength (YS) of 269 MPa and an elongation (EL) of 21%. The increase of Sm and Ce elements introduces the high density of micro-sized and nano-sized second phases as well as the Sm segregation at grain boundaries, which leads to an increase in the recrystallization fraction, more evident dynamic recrystallized (DRXed) grain refinement, and also the texture weakening. The increased density of nano-phases and the DRXed grains refinement lead to the higher strength, and the decrease in dislocation density and texture weakening contribute to the excellent ductility. The relevant work can shed light on designing other low-cost and high-performance Mg wrought alloys containing the cheap light rare-earth elements.