Abstract
In this paper we investigated the refinig effects of phosphorous additives to Al-20Si alloy melt changing melting temperature and holding time. Also we examined them by the direct addition of AlP considered to be a crystallizing nucleus of primary silicon. These experiments were based upon the measurement of the grain size of primary silicon, but at the same time we observed the cast structure in each case.
As an important result it has been made clear that the effect of phosphorous addition could be obtained only above the temperature of 850°C in case of red phosphorous, and above 800°C in the case of the other additives. We have also found that at the keeping time of 750°C a characteristic curve of each additives could be obtained and that each curve approached to nearly the same value of grain size. Using these results we have done some discussion of the behavior of refining nuclei of primary silicon crystals.
