| Title |
The Influence of Be Addition on the Coarsening Behavior and the Early Stage of Decomposition Process of δ' Phase in Binary Al - Li Alloys |
| Authors |
정동석(D . S . Chung); 은일상(I . S . Eun); 조현기(H . K . Cho) |
| Abstract |
To clarify the influence of Be addition on the coarsening behavior and the early stage of decomposition process of δ´phase in binary Al-Li alloys, the detailed measurement of micro vickers hardness and specific heat and the observation of transmission electron micrographs have been carried out. Al-Li-Be alloys were found to have higher hardening rate than the binary Al-Li alloy when aged at 190℃ and Be addition on binary Al-Li alloys promoted the early stage of decomposition process of metastable phases such as formation of ordered domains (δ´precursory structures). δ´precursory structures in the binary and ternary alloys were stable with aging time at 190℃. The split of endothermic peak R on the S-T their incompletely orderd structure and size effect, respectively. It was deduced that the coarsening rate constants of δ´phase in Al-Li-Be alloys were higher than that of the binary Al-Li alloy because of the change of interfacial characteristics of δ´phase which resulted from microsegregation of Be at interface between δ´phase and the matrix or Be incorporation into δ´phase. |