The present invention discloses a method of strip casting an aluminum alloy from immiscible liquids that yields a highly uniform structure of fine second phase particles. The results of the present invention are achieved by using a known casting process to cast the alloy into a thin strip at high speeds. In the method of the present invention, the casting speed is preferably in the region of about 50-300 feet per minute (fpm) and the thickness of the strip preferably smaller than 0.08-0.25 inches. Under these conditions, favorable results are achieved when droplets of the immiscible liquid phase nucleate in the liquid ahead of the solidification front established in the casting process. The droplets of the immiscible phase are engulfed by the rapidly moving freeze front into the space between the Secondary Dendrite Arms (SDA).