| Title |
Precipitation and Ripening Behaviours of Metastable Phases in Al - Li - Zr Alloy |
| Authors |
우기도(Kee Do Woo); 조현기(Hyun Kee Cho) |
| Abstract |
Precipitation and ripening behaviours of metastable phases in Al-2.33wt%Li-0.32wt% Zr alloy are studied by employing TEM. The δ`, Al₃Zr and composite phases are observed at the as-quenched state. Activation energy for the growth of matrix δ` phases is 31.5㎉/㏖ and the growth rate is affected by addition of Zr. We argue that the composite phase can be formed during quenching and aging by impingement of previously existing δ` and A1₃Zr phases followed by preferential coarsening of δin contact with the A1₃Zr, leading to encapsulation of the A1₃Zr by δ`. The Al₃Zr phase accelerates the nucleation and growth of δ` phase, and improves the mechanical properties such as hardness. |