Microstructure and mechanical properties of AZ91 alloy produced with ultrasonic vibration

Processing, microstructure and mechanical properties of magnesium matrix nanocomposites fabricated by semisolid stirring assisted ultrasonic vibration

“…Since nanoparticle clusters are loosely packed together, air, inert gas, or metal vapor can be trapped inside the voids in the clusters to serve as nuclei for ultrasonic cavitations. The ultrasonic cavitations continue to grow until collapse during the half-period of compression, thus producing a high intensity shock wave in the melt [22]. Under the action of high intensity of shock, the insoluble solid impurities including SiC nanoparticles throughout the melt become active and involve in the solidification of process as nuclei, which lead to the heterogeneous nucleation easily upon a slight undercooling.…”

Effects of ultrasonic treatment on microstructure and tensile strength of AZ91 magnesium alloy

“…Liu et al [18] and Gao et al [19] studied the effect of ultrasonic power on the microstructure and mechanical properties of AZ91 magnesium alloy. These investigations showed that UST resulted in formation of fine non-dendritic grains in the solidified microstructures.…”

“…The main mechanisms put forward in the literature to explain the role of cavitation in grain refinement of metals and alloys under UST can be classified as follows [6][7][8][9][12][13][14][15][16][17][18][19][20][21][24][25][26][27]:…”

Ultrasonic Grain Refinement of Magnesium and Its Alloys

“…It is also effective in grain-refining other metallic materials (Eskin, 1998;Jian et al, 2005;Jian et al, 2006a;Liu et al, 2007;Xu et al, 2008) and ice (Zhang et al, 2001). The recent renewed interest in the process for Mg alloys (Jian et al, 2006b;Ramirez & Qian, 2007;Zhang et al, 2007;Liu et al, 2008;Ramirez et al, 2008;Ramirez et al, 2009;Qian et al, 2010a) is driven by its potent grain-refining capability, ease of operation, and requirement for inexpensive equipment. In addition, the melt surface is left almost undisturbed during irradiation.…”