Microstructural evolution of 5754 under merged fields Num-Exp
Haghayeghi, E.Ezzatneshan, “Microstructural evolution of 5754 under merged fields: Num/Exp”, Materials Processing Technology”, Vol. 225, 2015, PP.103-109.
The effect of combined electromagnetic–ultrasonic fields evaluated on grain refinement. Cavitation induced by the combination of technologies suggested as major mechanism for grain refinement. A numerical simulation performed predicting the cavitation regions in the molten AA5754 aluminum alloy. It was concluded that the cavitation phenomenon occurs near the electromagnetic and ultrasonic sources. The observed acoustic streaming induced by ultrasonic horn is more intensive than the electromagnetic one. The ultrasonic streaming could transport small bubbles into the bulk rapidly. These micro-bubbles collapsed due to acoustic vibrations where the resulting micro-jets were strong enough to break the oxide layer, wetting impurities. Exogenous particles, intermetallic and oxides may contribute to the formation of fine, uniform and equiaxed microstructure across the treated melt. Experimental results confirmed the simulation predictions.