Influences of trace additions of strontium and phosphorus on electrical resistivity and viscosity of liquid Al-Si alloys

The electrical resistivity and viscosity of liquid hypoeutectic Al-7 % Si and hypereutectic Al-18 % Si alloys, and the influences of trace strontium and phosphorus on them were investigated. The trace additions of the two elements increase the electrical resistivity. At the precipitation temperatures of primary phase, the electrical resistivity exhibits a discontinuity for all experimental Al-Si alloys. In the discontinuity the electrical resistivity, respectively, decreases and increases abruptly for Al-7% Si alloys and Al-18 % Si alloys. Phosphorus and strontium both have some effects on the discontinuity temperature and the jump value of electrical resistivity of Al-18 % Si alloys, but strontium hardly has effect on them in Al-7 % Si alloys. The trace additions of strontium and phosphorus increase the viscosity of the experimental alloy.