Ultrasonic Processing and Microstructural Analysis of AZ91 Magnesium Alloy

Abstract

In the present study ultrasonic vibrations are used for the grain refinement of AZ91 alloy during its solidification. The microstructures and mechanical properties of the treated AZ91 alloy are characterized. It is found that due to the acoustic cavitation and flows induced by ultrasonic vibration during the nucleation stage, the formation of the fine uniform globular grains are attributed to the combination of the enhanced heterogeneous nucleation and dendrite fragmentation. The average grain size decreases with increase in ultrasonic intensity but the largest reduction occurs mainly from 1.34KW/cm2 to 2.69K W/cm2; the benefits of further increase in the ultrasonic intensity from 2.69KW/cm2 to 4.031KW/cm2 are small.

Processing of Magnesium-Based Metal Matrix Nanocomposites by Ultrasound-Assisted Particle Dispersion: A Review

“…An increase in the tensile strength was attributed to refinement of Mg 17 Al 12 and its less continuous distribution. Bhingole et al processed AZ91 with UST, as well [18,19]. Ultrasonic intensities of 1.34 kW/cm 2 , 2.69 kW/cm 2 , and 4.031 kW/cm 2 corresponding to amplitudes of 15 µm, 30 µm, and 45 µm respectively, were each applied for one minute.…”