Special nanostructures in Al-Mg alloys subjected to high pressure torsion

来源期刊：中国有色金属学报(英文版)2010年第11期

论文作者：刘满平 Hans J. ROVEN 刘新涛 Maxim MURASHKIN Ruslan Z. VALIEV Tamas UNGáR Levente BALOGH

文章页码：2051 - 2056

Key words：aluminum alloys; severe plastic deformation; high pressure torsion; grain boundary structure; deformation twinning; nanostructures

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.