抄録
In many cases, it is desirable to use soft aluminium which recrystallizes at room temperature. It would be convenient as well as economical, if such aluminum could be made easily and cheaply.
This research was successful in lowering the recrystallization temperature to below room temperature by the addition of a small amount of calcium to aluminium of commercial purity with high temperature soaking, and by heat treatment for a long time at low temperature. It was proved that the matrix of aluminium containing impurities could be almost completely purified by changing the impurities to a harmless state by the addition of calcium and by heat treatment. Consequently, the aluminium alloy obtained, besides having the property of softening at room temperature, has the properties excelling in softness, workability, electric conductivity and corrosion resistance peculiar to high purity aluminium.
Further, it was found that impurities such as magnesium, manganese and copper can be more readily changed to a harmless state by the addition of small amounts of tin, nickel, etc., together with calcium, and general properties of the elements, which can purify the matrix of aluminium by the addition of them, were studied.
