Nucleation and growth of high purity aluminum grains
in directional solidification bulk
sample without electromagnetic stirring
in directional solidification bulk
sample without electromagnetic stirring
(1. State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200030, China;
2. School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132, China;
3. Instruments Analysis Center, Shanghai Jiao Tong University, Shanghai 200030, China;
4. Analysis and Testing Center For Inorganic Materials, Shanghai Institute of Ceramics
Chinese Academy of Sciences, Shanghai 200037, China)
2. School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132, China;
3. Instruments Analysis Center, Shanghai Jiao Tong University, Shanghai 200030, China;
4. Analysis and Testing Center For Inorganic Materials, Shanghai Institute of Ceramics
Chinese Academy of Sciences, Shanghai 200037, China)
Abstract: A self-made directional solidification device was used to fabricate d 80 mm high purity aluminum ingots. SEM and AFM were used to detect the shape of grain boundaries. The orientation of the grain was studied by X-ray diffractometry. The results show that the nucleation points locate at the intersections of three adjacent grains. The lattice orientation of grains does not alter in the horizontal direction, but gradually approaches the optimum growth direction in the vertical direction during the growth process. All the grains suffer the competition and only the one whose orientation is closest to the preferred direction can occupy the final growth space.
Key words: high purity aluminum; directional solidification; grain nucleation; lattice orientation; competitive growth