抄録
When Al-bronze is slowly cooled, it shows a brittleness called “self-annealing phenomenon of Al-bronze”.
This phenomenon is caused by γ2 produced at β→α+γ2 transformation. Therefore the depressing of the self-annealing phenomenon poses an important problem from the engineering point of view, and it was made clear that additions of Fe and Mn are effective on the depressing of β→α+γ2 transformation.
The present study was intended to investigate the depressing effects of additions of Be and both Be and Fe on the β→α+γ2 transformation of Cu-Al alloy. For this purpose, the T.T.T. diagrams of these Cu-Al alloys were made out through examinations of microstructures. The results obtained are as follows: (1) The nose of Cu-Al-0.63Be alloy was about 462°C, 6.7×103 sec and the nose of Cu-Al-0.66Be-3.65Fe alloy was about 525°C, 1.2×103 sec. (2) Additional effects of Be and Fe on the depressing of β→α+γ2 transformation was not recognized. However, the isothermal transformation speed of Cu-Al-0.66Be-3.65Fe alloy was slightly slower than Cu-Al-3Mn alloy, and the addition of Be was effective for the depressing of β→α+γ2+κ transformation of Cu-Al-Fe alloy.
