Microstructure, texture and mechanical properties of as-extruded Mg-Zn-Er alloys

In the present work, the microstructure, texture and mechanical properties of the as-extruded Mg-xZn-yEr (x=3, 6 and 9; y=0.5,1 and 1.5; x/y= 6) alloys were investigated. The results showed that the I-phase in the as-cast alloys was destroyed and lots of nano-scale quasicrystalline particles were precipitated within the matrix during hot extrusion process. With the increase in the volume fraction of the primary I-phase, the particle-stimulated nucleation (PSN) of recrystallization was activated. It was suggested that the recrystallization via PSN should lead to the nucleation of new grains with a high orientation mismatch to the parent grains, making the texture gradually weaken. Significant strengthening is achieved in the Mg-9Zn-1.5Er alloy, of which the ultimate tensile strength (sigma(b)) and the yield tensile strength (sigma(0.2)) were 319 MPa and 192 MPa, respectively, with an elongation of 22.3%. (C) 2013 Elsevier B.V. All rights reserved.