Modification Mechanism and Microstructural Characteristics of Eutectic Si in Casting Al-Si Alloys: A Review on Experimental and Numerical Studies

Impact of P and Sr on solidification sequence and morphology of hypoeutectic Al–Si alloys: Combined thermodynamic computation and phase-field simulation

“…Coefficient set 1, which was applied to all simulations without Sr (indicated by green color in the figures), reflects the unmodified growth mode. It favors twinning with respect to a single (1 1 1)-plane and promotes growth in the six h1 1 2i-directions within this plane according to the widely accepted TPRE mechanism [3,4]. Set 2 models the Sr-modified growth kinetics (indicated by violet color).…”

“…A summary can be found in the reviews by [2][3][4]. Recent progress in the thermodynamic modeling of the AlSi-Sr-P system now offers the opportunity to test some of the proposed hypotheses by means of numerical simulation.…”

“…For a long time, Sr-modification was only explained by its impact on growth kinetics of the (Si) phase. The growth of the (Si) phase is governed by {1 1 1}-facets, however, internal twinning plays a dominant role [3,4]. The twin-plane re-entrant edge mechanism (TPRE) is generally accepted as leading growth mode.…”

The effect of Nb–B inoculation on binary hypereutectic and near-eutectic LM13 Al–Si cast alloys

“…brittle and hard Al-Si intermetallic particles) and primary silicon particles. More in detail, the eutectic phase present in Al-Si cast alloy is commonly characterised by a 3D planar (lath) or 2D acicular morphology [4] which can be useful in application where high wear resistance is required but it is detrimental for the ductility of the material. The morphology of this eutectic phase can be easily changed to fibrous by the addition of very small quantity (ppm) of calcium, sodium and strontium; a process known as modification [5][6][7][8][9].…”

Phase relationships of the R–Al–Si systems

“…The addition of a rare earth element (R) can improve the technological properties and the stability at high temperatures of these alloys, through the formation of ternary phases [1][2][3][4][5]. Moreover, the addition of rare earth metals to casting Al-Si alloys modifies their microstructures [6] inducing a lowering of the eutectic temperature; for this reason, a measure of the ''depression'' in the eutectic temperature value has been proposed as a method to control the modification level in the alloy microstructure by means of thermal analysis measurements [7,8].…”