Effect of Al Content on the Microstructural and Grain Growth Kinetics of Magnesium Alloys

In order to control the grain size in thermomechanical processing, growth behavior of hot extruded Mg–xAl–1Zn (x = 3, 6, 9) alloys and their relationship with second phase particles solutes were investigated. The rate AZ61 is greater than that AZ31 AZ91 at 300 °C, 350 400 450 °C under isothermal annealing. average exponents n 2.26, 2.33, 2.53 300–400 respectively. deviation from theoretical value 2 was attributed hindrance boundary migration Al-rich solute Al. Microscopic observations show annealed samples closely related shape, volume fraction, size, distribution position particles. Significantly, pinning effect stronger for lamellar network-like addition, plays a more important role refinement dragging abnormal grains microstructure high energy difference between preferentially oriented <112¯0> surrounding grains, which drives boundaries overcome same force