Morphology and Nucleation of Intermetallic Phases in Casting Al–Mg–Si Alloys

Effect of Al2Ca Addition and Heat Treatment on the Microstructure Modification and Tensile Properties of Hypo-Eutectic Al–Mg–Si Alloys

“…Therefore, the advanced Mg 2 Si, with the aforementioned morphologies, evolve from vertices <100> and edges <110> instead from faces {111} [ 21 ]. However, many recent studies related to hypo-eutectic Al–Mg–Si alloys reported the formation of lamellar eutectic structure as well as other morphologies such as Chinese script-like or flake-like morphology [ 11 , 17 , 18 , 21 ]. Trudonoshyn [ 21 ] also reported the triangular-spiral morphology.…”

“…It was stated that refinement was related to increased undercooling by the enrichment of Ca on the solid/liquid interface, and consequently, it restricted the growth of the primary α-Al phase. However, in another study [23], it was reported that Ca addition in inoculated Al-Si-Mg ternary alloys increases the nucleation of primary α-Al phases by promoting heterogeneous nucleation sites Al3Ti or Al2Cu, ported the formation of lamellar eutectic structure as well as other morphologies such as Chinese script-like or flake-like morphology [11,17,18,21]. Trudonoshyn [21] also reported the triangular-spiral morphology.…”

“…In Al-Si alloy, AlP particles are considered nucleating agents for Si eutectic phases. It was reported that Sr decreased the From the literature, two mechanisms are responsible for modification/refinement of eutectic structure on the addition of a modifier element [16,18,19,[22][23][24][25][26]; (1) The modifier element, either in the form of oxides or thermally stable intermetallic compounds, act as nucleation sites for eutectic phases or it should deactivate the potency of nucleating agents present in the melt (which are usually present in small amount as an impurity), and (2) is through restricting the growth of these phases by changing the interface energy of solid/liquid interface. In the case of Al-Mg-Si ternary alloys, different nucleation sites are reported for the primary Mg 2 Si phases, upon which eutectic phases are formed.…”

“…Ji [11] developed a hypo-eutectic Al-Mg 2 Si alloy (with approximately 4 wt% Mg 2 Si) based novel die casting alloy with high strength accompanied by high ductility. Following that, few studies were conducted regarding the evolution of eutectic microstructure in this newly developed alloy [14][15][16][17][18]. Zhu [5] recently studied the effect of varying amounts of extra Si and Mg on eutectic phases in Al-Mg 2 Si alloy processed by high pressure die casting.…”