Investigation on corrosion behavior and mechanical properties of an extruded Mg-Zn-Al-Sn-Mn alloy

Mg alloy with the alloying elements of Zn, Al, Sn and Mn was designed, and hot extrusion was carried out under various extrusion speeds and temperatures. The microstructure was well characterized, and the mechanical properties as well as corrosion resistance were tested. The results showed that the high speed extrusion resulted in more second phase particles, an increase in fraction of dynamic recrystallized (DRXed) grains, and a weaker basal plane texture. Moreover, high extrusion temperature increased the number of second phases, grain size, and DRX degree, while decreased the strength of basal plane texture. The sample extruded under the speed of 10 mm/min and temperature of 300 degrees C exhibited the highest yield strength (YS) and ultimate tensile strength (UTS), and the best corrosion resistance. High extrusion temperature could reduce the strength, while increase the elongation (EL). The corrosion resistance was improved greatly by grain refinement, while it became worse by increasing the number of fine and dispersed second phase particles.