The influence of Gd on the recrystallisation, texture and mechanical properties of Mg alloy

Abstract

Microstructure, texture and mechanical properties of extruded Mg-xGd sheets (x = 1.0, 1.5, 2.0 and 2.5 wt%) were discussed, and microstructural evolution of an Mg-1.0Gd alloy during extrusion were investigated. The extruded Mg-xGd sheets presented a fully recrystallized microstructure. The texture with [112‾1]-[202‾1] double fibre orientations was observed in all the extruded sheets, and texture weakening was observed with increasing Gd content. With an increase in Gd content, the tensile strength of the sheets gradually increased mainly due to the fine grain size and more Gd atoms, and an increase in ductility was related to the fine grain size, more Gd atoms and higher Schmid factor for basal slip. During extrusion, the development of compression twins and {101‾1}-{101‾2} double twins played a key role in the formation of [112‾1]-[202‾1] double fibre texture. Fine recrystallized grains having an unusual texture with [112‾1]-[202‾1] double fibre orientation preferentially formed in the undynamically recrystallized matrix with [101‾0] fibre orientation via continuous dynamically recrystallization and have grown along well-defined bands. Further extrusion deformation resulted in a fully recrystallized microstructure with an unusual texture.