Microstructures and mechanical properties of AZ80 alloy treated by pulsed ultrasonic vibration

Pulsed ultrasonic field was employed in the melt of the AZ80 magnesium alloy. The effects of pulsed ultrasonic field on microstructure and mechanical properties of AZ80 magnesium alloy were investigated. The results show that the as-cast microstructure of the AZ80 alloy with pulsed ultrasonic treatment is significantly changed. Pulsed ultrasonic field significantly decreases the grain size, changes the morphologies of the β-Mg17Al12 phases and reduces their area fraction. It is found that pulse width of ultrasonic plays an important role on the microstructure formation of AZ80 alloy. With increasing pulse width, grains become finer and more uniform. In the range of experimental parameters, the optimum pulse width for melt treatment process is found to be 210 μs. The mechanical tests show that the mechanical properties of the as-cast AZ80 magnesium alloy with pulsed ultrasonic treatment are much higher than those of AZ80 alloy without ultrasonic field.