Effect of Ultrasonic Melt Treatment on Degassing and Structure of Aluminium Alloys

Abstract

Ultrasonic processing is known to be an efficient means of aluminium melt degassing and structure modification with additional benefits of being economical and environment friendly. This paper reports on the kinetics of ultrasonic degassing effect of foundry alloys. Direct measurements of hydrogen concentration in the melt by Foseco Alspek-H probe are used along with the reduced-pressure test. The effects of ultrasonic processing on structure, i.e. grain size and porosity, are studied using metallography and 3D X-ray tomography. This work is performed within the Ultragassing project funded by the European Union’s 7th Framework Program.

Ultrasonic Vibration as a Primary Mixing Tool in Accelerating Aluminum–Copper Alloys Preparation from Their Pure Elements

“…Without the existence of Ti, the survival of the nucleus is difficult, since the melt of Al-8Cu was ultrasonically-treated in a temperature far from its liquidus temperature. Several studies reported a poor refining effect of USV using a sonotrode with Nb tip (no dispersion and dissolution of TiAl 3 ) in a temperature higher than the liquidus temperature of the treated alloy [41,42]. In the current study, only few bulky TiAl 3 particles ( Figure 17) were observed in the center of some grains.…”

Evaluation of effect of ultrasonic degassing on components produced by low pressure die casting

“…However, the final hydrogen content, once the metal is transferred to the LPDC crucible, remains on the same level for both processes (0.47 vs 0.45 ml/100g). This actually shows that the tendency to melt regassing is higher in the case of the conventional process, which can be also related to the dross formation 13 .…”

Ultrasonic degassing of aluminium alloys: Basic studies and practical implementation

“…The actual amount of porosity in samples solidified under normal pressure conditions decreases three times, from 1.6 to 0.3 vol.%. The microstructure of the as-cast alloys does not change much with ultrasonic processing as it is performed at a rather high temperature and cannot directly affect solidification conditions [16].…”