Abstract
A new technique for the measurement of the interfacial energy between an Al-Si eutectic melt and solid Si was proposed, based on the equilibrium dihedral angle at the Si grain boundary. Pure Si having one right angled grain boundary at the surface was used as for the solid sample. And as for the liquid sample, pure Al and Al containing 0.16 mass%Sr were adopted.
A liquid sample was placed on the Si and heated in a vacuum. Just after melting of the liquid sample, the temperature of the sample was cooled to 853 K rapidly and held for 5 h. From the grain boundary grooves, we measured the dihedral angles and calculated the interfacial energy between the Al-Si eutectic melt and solid Si. The dihedral angle changed from 79.6±5.1° to 63.2±4.7° with the addition of Sr. We confirmed that the decreasing rate in interfacial energy was more than 10% with the addition of Sr. This result supports the interfacial energy theory for the modification mechanism in Al-Si alloys.
