中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 26 No. 10 October 2016 |
（1. Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Ministry of Education,
School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China;
2. Laboratory of Special Processing of Raw Materials, Dalian University of Technology, Dalian 116024, China）
Abstract:Homogenization annealing of the 7050/6009 bimetal slab prepared by direct-chill casting was investigated and its effects on microstructural evolution, composition distribution and mechanical properties in the interfacial region of the bimetal were studied. The results show that the optimized homogenization annealing process was 460 °C for 24 h. After homogenization annealing, the Zn-rich phases and Al15(FeMn)3Si2 phases were precipitated at the interface of the bimetal. The diffusion layer thickness of homogenized bimetal increased by 30 μm from 440 to 480 °C for 24 h, while it increased by 280 μm from 12 to 36 h at 460 °C. The Vickers hardnesses at 6009 alloy side and interface of the bimetal decreased after homogenized annealing and grain coarsening was considered as the dominating softening mechanism. The hardness variation at 7050 alloy side was complicated due to the combined action of solution strengthening, dispersion strengthening and dissolution of reinforced phases.
Key words: bimetal slab; homogenization annealing; microstructure; diffusion layer; mechanical properties
