| Title |
High Resolution electron Microscopic Study of the Precipitation Behavior in Al - Li - Cu - Mg - Zr Alloy |
| Authors |
이신호(Kap Ho Lee); 황돈하(Don Ha Hwang); 조성길(Seong Gill Cho); 주승원(Seoung Woon Lee); 이응조(Yeung Jo Lee) |
| Abstract |
The precipitation behavior in Al-2.28wt%Li-1.11wt%Cu-0.57wt%Mg-0.18wt%Zr alloy has been studied by using a high resolution electron microscope. In the alloy quenched from 530℃, the Ll₂-type microdomains with a few unit cells and regions having lattice modulation parallel to {100} planes are observed in an atomic resolution image. After an aging at 190℃ for 10min, the discrete δ´-ordered precipitates with 4 to 8㎚ in size are recognized in fcc disordered matrix. In the θ´/δ´complex precipitates, interface boundary on both faces of θ´ plate is atomically flat and coherent with surrounding δ´ phase and an antiphase relation is formed between the δ´ phases on both faces of θ´ plate. Nucleation sites of S´ phase are observed at not only δ´/matrix interface and subgrain boundary, but Cu and Mg clusters. In the β´/δ´ complex precipitates, β´ and δ´ phases are slightly misoriented with respect to each other and a lattice misfit of about 10㎚ width is partially observed in the interface boundary. |