Hot deformation behavior of hot-rolled AZ31 and AZ61 magnesium alloys

The hot deformation behavior and microstructure of AZ31 and AZ61 alloys processed by the hot-rolled technique were investigated over a strain rate range from 1×10^-4 to 1×10^-1s^-1 and temperatures ranging from 350 to 500°C. Alloys were manufactured by melting and casting, and then hot-rolled at two temperatures of 350 and 450°C. Tensile test revealed elongations of over 300% in the two alloys. The highest elongation value of 321% at a strain rate of 3×10^-3s^-1 was achieved in the AZ61 alloy with a hot-rolling temperature of 350°C. The hot tensile tests showed that there are some differences in ductility between the AZ31 and AZ61 alloys with the same rolling process specifically at low strain rates. A small enhancement in ductility is found using a lower temperature for hot-rolling at 350°C compared to 450°C due to improved grain refinement. It is suggested that the dominant deformation mechanism was glide controlled dislocation creep based on the stress and grain size exponent, and activation energy.