Microstructural characterization of an extruded Mg-Ni-Y-RE alloy processed by equal channel angular extrusion

Equal channel angular extrusion (ECAE) was performed in a conventionally extruded Mg-Ni-Y-RE material to develop fine-grained microstructures. The microstructure of the extruded alloy consisted of agglomerated phase particles zones (APZs) aligned along the extrusion direction and phase particles free zones (PFZs) containing recrystallized magnesium grains smaller than 5 μm in size. Some PFZs contained a banded unrecrystallized structure. The global texture was very weak and described by a (1 0 0) fibre which is common in extruded magnesium alloys. PFZs grain size was reduced to less than 1 μm after ECAE deformation at temperatures of 275, 310 and 375 °C, although some PFZs remained unrecrystallized. The mechanical properties of ECAE deformed materials were correlated with grain size and texture.