抄録
We have studied the martensite transformation of Cu-Al binary alloys which contained 12, 18%Al. From the results of our experiment, we found that there were two types of β′ transformed from β by martensitic way when β was cooled with different velocities. The one type occurred when the Vc (cooling velocity) became greater than 500°C/min, and a large expansion appeared at about 320°C on the cooling dilatation curve. Then it was thought that the martensite transformation took place at 320°C, and we could recognize the needle-like martensitic structure by microscopic observation. On the other hand, the another type occurred at the condition of 500°C/min>Vc>15°C min, and in this case, a contraction appeared at about 280°C on the cooling dilatation curve. By microscopic observation of this specimen we could not find the so-called martensitic feature, but nevertheless it seems sure that the β′ of this type had some martensitic properties, judging from the experimental results of thermal dilatation and electric resistance about it.
