| Title |
Transformations of β- Cu ·Al Alloys During Continuous Cooling (1) |
| Abstract |
The continuous cooling phase transformations (CCT) in copper-aluminum alloys (11.1∼13.3 wt.% Al) have been studied. Five CCT diagrams have been constructed by dilatometry and thermal analysis. At higher cooling rates, the phase transformations are characterized by an ordering reaction and a martensite transformation. When the cooling rate is lowered, the ordering reaction of the matrix influences the subsequent transformations and thus a bainite transformation occurs. After proeutectoid precipitation, two ordering reactions and two martensite transformations are observed. On the other hand, at slow cooling an ordering reaction at about 270℃ is observed for all the studied alloys. This ordering corresponds to that of the α` or α`_p phase in which aluminum has been depleted. Eutectoid transformation at about 500℃ is observed at very slow cooling. |