Theoretical design and distribution control of precipitates and solute elements in Al-Zn-Mg-Cu alloys with heterostructure
(1. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China;
2. Beijing Laboratory of Metallic Materials and Processing for Modern Transportation, University of Science and Technology Beijing, Beijing 100083, China;
3. Baowu Aluminum Technical Center, Baosteel Central Research Institute, Baoshan Iron & Steel Co., Ltd., Shanghai 201900, China;
4. Sanmenxia Aluminum-based New Material R&D Center, China Baowu Steel Group, Sanmenxia 472099, China)
2. Beijing Laboratory of Metallic Materials and Processing for Modern Transportation, University of Science and Technology Beijing, Beijing 100083, China;
3. Baowu Aluminum Technical Center, Baosteel Central Research Institute, Baoshan Iron & Steel Co., Ltd., Shanghai 201900, China;
4. Sanmenxia Aluminum-based New Material R&D Center, China Baowu Steel Group, Sanmenxia 472099, China)
Abstract: In order to simultaneously improve strength and formability, an analytical model for the concentration distribution of precipitates and solute elements is established and used to theoretically design and control the heterogeneous microstructure of Al-Zn-Mg-Cu alloys. The results show that the dissolution of precipitates is mainly affected by particle size and heat treatment temperature, the heterogeneous distribution level of solute elements diffused in the alloy matrix mainly depends on the grain size, while the heat treatment temperature only has an obvious effect on the concentration distribution in the larger grains, and the experimental results of Al-Zn-Mg-Cu alloy are in good agreement with the theoretical model predictions of precipitates and solute element concentration distribution. Controlling the concentration distribution of precipitates and solute elements in Al-Zn-Mg-Cu alloys is the premise of accurately constructing heterogeneous microstructure in micro-domains, which can be used to significantly improve the formability of Al-Zn-Mg-Cu alloys with a heterostructure.
Key words: Al-Zn-Mg-Cu alloys; concentration distribution; diffusion; heterogeneous microstructure; model