Effect of strontium on liquid structure of Al–Si hypoeutectic alloys using high-energy X-ray diffraction

Microstructure evolution and modification mechanism of the ytterbium modified Al–7.5%Si–0.45%Mg alloys

“…The modifying agents can poison the active nucleation sites and results in a significant undercooling of the interdendritic liquid at the eutectic temperature, resulting in modification of eutectic silicon [24]. Furthermore, it is also proposed that the addition of modifying agent alters the liquid atomic structure and interfacial energy of the alloy [24,30]. However, these assertions have generated some controversy while the role of the particles remains unresolved [31,32].…”

“…It has been proposed that the ␤-(Al, Si, Fe) phases [25,26] or AlP particles [27][28][29] play an important role in the nucleation of the eutectic phases in hypoeutectic Al-Si alloys. The modifying agents can poison the active nucleation sites and results in a significant undercooling of the interdendritic liquid at the eutectic temperature, resulting in modification of eutectic silicon [24]. Furthermore, it is also proposed that the addition of modifying agent alters the liquid atomic structure and interfacial energy of the alloy [24,30].…”

“…However, there are a few dissenting publications about the effect of RE on eutectic modification in hypoeutectic Al-Si alloys [21][22][23]. The IIT mechanism that addition of modifying agent alters the growth of the silicon phase during solidification is now widely contested [24]. Although twins are frequently observed in silicon crystals, twinning is not believed to be the sole effective mechanism of modification.…”

Heredity of medium-range order structure from melts to the microstructure of Ni–Cr–W superalloy

“…However, only a little work is focused on the liquid structure of high melting-point alloy, especially for superalloy, and few are concentrated on the structural evolution in the solidification process especially near the liquidus temperature. The appearance and propagation of the atomic cluster would result in evolution of microstructure [10,11]. At present, compared with their nucleation and growth from the liquid, less is still known about their initial stages before solidification.…”

Twin-controlled growth of eutectic Si in unmodified and Sr-modified Al–12.7%Si alloys investigated by SEM/EBSD

“…Under such a mechanism, Si crystals grow preferentially in h1 1 2i directions [9,12]. http The chemical modification of eutectic Si crystals in Al-Si alloys may be associated with different mechanisms [1,[13][14][15][16][17][18][19]. Regarding the Si nucleation, an addition of Sr or Na modifier is considered to reduce the potential AlP nucleation sites in Al-Si melt by forming Sr 3 P/Na 3 P [20,21] or Al 2 Si 2 Sr [22], which causes the eutectic Si nucleation at large undercooling.…”