Microstructures and mechanical properties of Mg-2Y-1Mn-1-2Nd alloys fabricated by extrusion

Microstructures and mechanical properties of the extruded Mg-2Y-1Mn-1 Nd and Mg-2Y-1Mn-2Nd alloys were investigated. The coarse Mg12Nd phase particles and fine Mg24Y5 precipitations form in the Mg-2Y-1Mn-2Nd alloy and distribute at the grain boundaries and in the grain interior, but were not observed in the Mg-2Y-1Mn-1 Nd alloy due to its relatively lower Nd content. Tensile tests demonstrated that the Mg-2Y-1Mn-1Nd alloy exhibits slightly higher yield and ultimate tensile strengths, but lower elongation to failure at room temperature as compared with the Mg-2Y-1Mn-1Nd alloy. In contrast, the Mg-2Y-1Mn-2Nd alloy shows higher yield and ultimate tensile strengths and higher elongation to failure at 100 degrees C, 200 degrees C and 300 degrees C than the Mg-2Y-1Mn-2Nd alloy. These differences in the tensile mechanical properties of the Mg-2Y-1Mn-2Nd alloy and the Mg-2Y-1Mn-1Nd alloy arise from the strengthening due to the grain refinement and the precipitation strengthening generated by the coarse Mg12Nd phase particles and the fine Mg24Y5 precipitations. (C) 2010 Elsevier B.V. All rights reserved.