Preparation and Characterization of As-Cast and As-Extruded Mg-1Mn-0.6Ce-3Y Alloy

Mg-1Mn-0.6Ce-3Y alloy was prepared by metal mould casting method. The as-cast ingot was homogenized and then hot-extruded by an extrusion ratio of 16:1 at 380 °C. Microstructure and mechanical properties of the as-cast and hot-extruded samples were investigated. The results showed that the as-cast sample mainly consisted of α-Mg, Mg12Ce, and Mg24Y5 phases. The average grain size of the sample homogenized at 380 °C was about 100μm, and it was greatly refined to about 6μm by dynamic recrystallization for the hot-extruded sample. The ultimate tensile strength, 0.2% yield strength and elongation of the hot-extruded sample were 244 MPa, 178 MPa and 37.5%, respectively. They were enhanced by 82%, 197% and 400%, correspondingly compared with those of the as-cast sample. The improvement of the strengths was attributed to the grain refinement, breakup of the precipitates and increase of the dislocation density.