Effects of nano-sized TiB2 particles and Al3Zr dispersoids on microstructure and mechanical properties of Al-Zn-Mg-Cu based materials
(1. State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China;
2. School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
3. Anhui Provincial Engineering Research Center of Aluminium Matrix Composites, Huaibei 235000, China;
4. Shanghai Aircraft Design and Research Institute, Shanghai 201203, China;
5. Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240, China)
2. School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
3. Anhui Provincial Engineering Research Center of Aluminium Matrix Composites, Huaibei 235000, China;
4. Shanghai Aircraft Design and Research Institute, Shanghai 201203, China;
5. Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240, China)
Abstract: The effects of TiB2 and Zr on the microstructure, aging response and mechanical properties of hot-extruded Al-Zn-Mg-Cu based materials were investigated and compared by multi-scale microstructure characterization techniques. The results showed that proper addition of TiB2 particles could refine grain size during solidification, promote dynamic recrystallization during extrusion, and inhibit grain growth during solution treatment. Meanwhile, Zr addition had minor influence on the grain refinement during solidification, but could effectively suppress recrystallization and grain growth compared with the Zr-free alloy. Furthermore, the TiB2 addition could simultaneously enhance the aging kinetics and peak-aged hardness of the materials. Comparatively, Zr addition could also improve the peak-aged hardness with minor effect on the aging kinetics of the materials. Finally, the quench sensitivity, elastic modulus and tensile properties of the materials were compared and studied. Specifically, the relationship between the microstructure and mechanical properties, and the strengthening mechanisms were discussed in detail.
Key words: TiB2; Al3Zr; microstructure; aging kinetics; mechanical properties