the hot cracking tendency of Al-Cu alloys is investigated. The results suggest that the magnitudes of the strength and failure strain of the" alloys during solidification are not likely to be related to the hot cracking tendency. The tendency is in ralation to the extent of temperature range of hot brittleness and the rate of strength increase in this temperature range. A wider temperature range or a faster rate of increasing strength in that range would result in an easier formation of concentrated strain