Fourier thermal analysis of solidification kinetics in molten aluminium and in presence of ultrasonic field

In this paper a comparison between the Newtonian and Fourier method analysis available in thermal analysis techniques is reported. The experimental solidification of liquid aluminium under various conditions has been studied. Thermal analysis is a tool in elucidating the thermal events involved in liquid to solid transformation. The Newtonian method predicts a maximum in heat generation at the onset of solidification, while the Fourier method incorporates the effect of thermal gradient and predicts two heat generation peaks during the solidification process. This comparison between the Fourier and Newtonian method indicates that their predictions are appreciably different. In order to elucidate the effect of ultrasonic waves on solidification process, the measurements were carried out under similar conditions both with and without sonication. Our studies have shown that in presence of the ultrasonic field the kinetics of solidification is changed, leading namely to a decreased undercooling degree of the melt and thermal diffusivity.