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

Abstract

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 (σb) and the yield tensile strength (σ0.2) were 319MPa and 192MPa, respectively, with an elongation of 22.3%.