Effect of Microstructural Refinement on Tensile Properties of AZ80 Magnesium Alloy via Ca Addition and Extrusion Process

The microstructure and tensile properties of AZ80+X%Ca (X=0, 0.1, 0.5) magnesium alloy have investigated after applying extrusion process at 280 °C and 340 °C. Optical and scanning electron micrographs parallel to extrusion direction at 280 °C showed dynamically recrystallized grains. There were also initial grains elongated in extrusion direction in the AZ80+X%Ca alloy. Finer microstructures were observed by increasing calcium content due to the formation of some precipitates during grain growth. EDS analysis determined the newly formed precipitates as Al2Ca. The grain size was reduced from 90 μm to 9 μm by extrusion process in the sample with 0.5% Ca. At higher extrusion temperature (340 °C), similar microstructure was observed, except that the grain size was increased and there was no initial grains left in the structure anymore. From tensile testing, ultimate tensile strength (UTS) value was increased from 304 MPa to 329 MPa in extruded AZ80+0.5%Ca alloy at 280 °C.