中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 20 No. 11 November 2010 |
（1. National Engineering Research Center of Light Alloy Net Forming,
Shanghai Jiao Tong University, Shanghai 200240, China;
2. Department of Materials Science and Engineering,
Norwegian University of Science and Technology, Trondheim 7491, Norway;
3. Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, Ufa 450000, Russia;
4. Department of Materials Physics, Eötvös University, Budapest H-1518, Hungary）
Abstract:Deformation twins and stacking faults were observed in nanostructure Al-Mg alloys subjected to high pressure torsion. These observations are surprising because deformation twinnings have never been observed in their coarse-grained counterparts under normal conditions. Experimental evidences are introduced on non-equilibrium grain boundaries, deformation twinnings and partial dislocation emissions from grain boundaries. Some of these features can be explained by the results reported from molecular-dynamics simulations of pure FCC metals. Special emphasis is laid on the recent observations of high density hexagonal and rhombic shaped nanostructures with an average size of 3 nm in the Al-Mg alloys processed by high pressure torsion. A possible formation process of these nanostructures is proposed based on molecular-dynamics simulations.
Key words: aluminum alloys; severe plastic deformation; high pressure torsion; grain boundary structure; deformation twinning; nanostructures
