The effect of electromagnetic stirring on macrostructure and macrosegregation in the aluminium alloy 7150

Mechanism of grain refinement of an Al–Zn–Mg–Cu alloy prepared by low-frequency electromagnetic casting

“…The fragmentation whether by breaking dendrite arms or remelting dendrites arm root has also been used to explain the grain-refining effect of electromagnetic field [7,12,17,25,29,[32][33][34]. However, in terms of the grain refinement of Al-Zn-Mg-Cu alloy by LFEC process, there are still some inexplicable points of the fragmentation.…”

“…In the absence of effective nucleation substrates, dendrite fragments should be the major source of the equiaxed grain formation [31]. Therefore, the fragmentation caused by the forced convection has been used to explain the grain refinement [7,12,17,25,29,[32][33][34] under the influence of electromagnetic field. However, there is also another point of view that the forced convection cannot break the dendrite arm under normal solidification conditions [35,36].…”

Microsoft Word - 21_ Wróbel _final

“…www.intechopen.com The influence of electromagnetic field on liquid metal in aim of structure refinement (Fig.15), axial and zonal porosity elimination and obtaining larger homogeneity of structure, was applied in permanent mould casting (Griffiths & McCartney, 1997;Szajnar & Wróbel, 2008a, 2008b, 2009 and mainly in technologies of continuous (Adamczyk, 2004;Gillon, 2000;Harada, 1998;Miyazawa, 2001;Szajnar et al, 2010;Vives & Ricou, 1985) and semi-continuous casting (Guo et al, 2005). In case of continuous ingots of square and circular transverse section, rotating electromagnetic field induction coils are used.…”

Reconstruction and Quantitative Characterization of Multiphase, Multiscale Three-Dimensional Microstructure of a Cast Al-Si Base Alloy

“…[8] The primary Si particles often are coarse and have complex, faceted polyhedral shapes. [9,10] These coarse particles adversely affect the machinability of the alloy.…”

“…[6,7] Because of the divorce nature of the Al-Si eutectic, depending on the local cooling rate and composition, primary Si particles (i.e., the Si particles formed during solidification of the alloy before the eutectic reaction) also can form in the eutectic and near-eutectic Al-Si alloys. [8] The primary Si particles often are sparsely spaced, coarse, and have complex faceted polyhedral shapes. [9,10] Therefore, the 3D microstructure of cast Al-Si base alloys contains numerous constituents of complex shapes/morphologies; some of these constituents/phases are spaced sparsely; spatial correlations exist among the constituents/phases; and the length scales of different types of microstrucutral features can span over two orders of magnitude (e.g., eutectic Si platelets have thickness on the order of few microns, whereas gas pores can be of a few microns to a few hundred microns in size [6,7] ).…”