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Refinement and thermal analysis of hypereutectic Al 25%Si alloy were investigated with scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The results show that the average size of primary silicon in Al 25%Si alloy without and with phosphorus addition are 250 μm and 30 μm, respectively. But the primary and eutectic growth temperature is raised by about 17.3 ℃ and 4?℃ respectively due to phosphorus addition. The primary nucleation temperatures are 745.0 ℃ and 762.0 ℃ for untreated and treated samples and in addition, the enthalpy changes of primary and eutectic transformation are -261.0 J/g and -397.3 J/g without phosphorus addition, -294.2 J/g and -386.1 J/g with phosphorus addition, respectively. Otherwise the mechanisms of refinement and thermal transformation of Al 25%Si alloy in solidifying process are also discussed. [
Refinement and thermal analysis of hypereutectic Al 25% Si alloy were investigated with scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The results show that the average size of primary silicon in Al 25% Si alloy without and with phosphorus addition The primary nucleation temperatures are at 745.0 ° C and 762.0 ° C for untreated and treated samples and in addition, the enthalpy changes of primary and eutectic transformation are -261.0 J / g and -397.3 J / g without phosphorus addition, -294.2 J / g and -386.1 J / g with phosphorus addition, respectively. Otherwise the mechanisms of refinement and thermal transformation of Al 25% Si alloy in solidifying process are also discussed. [