Ultrasonic Processing and Microstructural Analysis of AZ91 Magnesium Alloy
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.
Asim Tewari, Satyam Suwas, Dinesh Srivastava, Indradev Samajdar and Arunansu Haldar
P. P. Bhingole et al., "Ultrasonic Processing and Microstructural Analysis of AZ91 Magnesium Alloy", Materials Science Forum, Vols. 702-703, pp. 975-978, 2012