中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 26 No. 4 April 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:6009/7050 alloy bimetal slab was prepared by a direct-chill (DC) casting process. Homogenizing annealing, hot rolling and T6 treatment were successively performed and their effects on microstructure and properties of the slab were studied. The results reveal that the average diffusion layer thickness of as-cast slab, determined by interdiffusion of elements Zn, Cu, Mg and Si, was about 400 μm. Excellent metallurgical bonding was achieved because all tensile samples fractured on the softer 6009 alloy side after homogenizing annealing. After homogenizing annealing plus rolling, the average diffusion layer thickness decreased to 100 μm, while the network structure of 7050 alloy side transformed to dispersive nubby structure. Furthermore, subsequent T6 treatment resulted in diffusion layer thickness up to 200 μm and an obvious increase of the Vickers hardness for both 7050 and 6009 sides. The layered structure of the as-cast 6009/7050 bimetal is retained after hot rolling and T6 treatment.
Key words: 7050 alloy; bimetal slab; direct-chill casting; heat treatment; hot rolling
