中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 7 July 2014 |
（1. Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education,
School of Materials Science and Engineering, Beihang University, Beijing 100191, China;
2. Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan;
3. Center for Advanced Die Engineering and Technology, Gifu University,
1-1 Yanagido, Gifu City, Gifu 501-1193, Japan;
4. Hebei Sitong New Metal Material Co., Ltd., Baoding 071105, China）
Abstract:To investigate the effects of Al-Ti-B-RE grain refiner on microstructure and mechanical properties of Al-7.0Si-0.55Mg (A357) alloy, some novel Al-7.0Si-0.55Mg alloysadded with different amount of Al-5Ti-1B-RE grain refiner with different RE composition were prepared by vacuum-melting. The microstructure and fracture behavior of the Al-7.0Si-0.55Mg alloys with the grain refiners were observed by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), and the mechanical properties of the alloys were tested in mechanical testing machine at room temperature. The observation of Al-Ti-B-RE morphology and internal structure of the particles reveals that it exhibits a TiAl3/Ti2Al20REcore-shell structure via heterogeneous TiB2 nuclei. The tensile strength of Al-7.0Si-0.55Mg alloys with Al-5Ti-1B-3.0RE grain refiner reaches the peak value at the same addition (0.2%) of grain refiner.
Key words: A357 alloy; Al-5Ti-1B grain refiner; rare earth; fracture; refining effect; tensile strength
