Wachstum von Silizium-Primärkristallen in übereutektischen Schmelzen. Langsame und schnelle Abkühlung, Dotieren der Schmelze mit Phosphor. Eutektische Reaktion. Erstarren einer mit Natriumsalzen veredelten eutektischen Al-Si-Legierung. Vergleich mit einer unveredelten Legierung. Mit Zeitdehnung und Zeitraffung.

The crystallization process of aluminium-silicon alloys is observed and filmed through a high-temperature microscope. The film shows the growth of primary silicon crystals in hyper-eutectic melts under slow and rapid cooling and with doping of melt with phosphorus. The eutetic reaction which concludes solidification is also shown, and investigated further, at varying cooling rates in the subsequent sequences. Solidification of an aluminium-silicon alloy modified by sodium salts addition, whose crystallization behaviour is comparable to that of a rapidly cooled unmodified alloy, concludes the film.