Influence of the amount of KBF4 on the morphology of Mg2Si in Mg–5Si alloys

Modification of Mg2Si in Mg–4Si Alloys with B

“…1(f), 1(g) be introduced to the melts in the form of Mg-30B modifier at 800°C. According to the previous study, 7,15) the mechanism of B modification is attributed to the adsorption and poison manners. Besides, from the fact that the amount of the primary Mg 2 Si considerably increases with the addition of Mg-B modifier (Figs.…”

“…This result is similar to the mechanism of KBF 4 modification on the primary Mg 2 Si in Mg-5Si alloy. 15) …”

Influences of Morphology and Size of Mg2Si on Microstructural Evolution of Mg–6.2Si Alloys during Partial Remelting

“…1,2) The partial remelting isothermal treatment of magnesium alloys, which has low processing temperature, can effectively resolve the problem of oxidation and burning 3) and improve the tensile properties at room temperature of the alloys. 4) The partial remelting process, during which the alloy is heated to the temperatures between solidus and liquidus and held in the semi-solid state, has unique advantage for fulfilling the semi-solid non-dendritic microstructure during heating prior to thixoforming.…”

“…5,6) Actually, amongst various magnesium alloys, Mg-Si alloys have attracted particular attention due to the excellent combination of various properties which mainly depend on the morphology and size of Mg 2 Si. 1,[7][8][9][10][11] However, the hypereutectic Mg-Si alloys show low ductility and strength because of the coarse dendritic primary and brittle Chinese script eutectic Mg 2 Si phases obtained by traditional casting route. 1,[7][8][9][10][11] It is well established that refinement and/or spheroidization of microstructure are mainly responsible for the improvement in the mechanical properties.…”

“…Details of the fabrication process of Mg-high Si alloys unmodified and modified with KBF 4 were described in elsewhere. 1,8) The unmodified and KBF 4 -modified Mg-6.2Si melts were manually stirred for about 2 min using a stainless steel impeller, held at ϳ800°C for 3 min, and then poured into a copper mold with the holes of f20 mmϫ100 mm and f6 mmϫ100 mm preheated at ϳ120°C, respectively.The partial remelting experiment was performed in an electric resistance furnace under a protective atmosphere of flowing gas of SF 6 (0.6 vol%) and CO 2 (Bal.). When the furnace was heated to 500°C, the circular column samples (f20 mmϫ10 mm and f6 mmϫ10 mm) were placed in the furnace.…”