A convergent-beam electron diffraction study of strain homogeneity in severely strained aluminum processed by equal-channel angular pressing

作者：Alhajeri Saleh N; Fox Alan G; Langdon Terence G^*

来源：Acta Materialia, 2011, 59(19): 7388-7395.

DOI：10.1016/j.actamat.2011.08.018

• Convergent-beam electron diffraction
• Equal-channel angular pressing
• Long-range internal stresses
• Severe plastic deformation
• Strain inhomogeneity

Aluminum of commercial purity was processed by equal-channel angular pressing (ECAP) through two, four and eight passes at room temperature. A series of [1 1 4] convergent-beam electron diffraction (CBED) zone axis patterns were obtained using an electron probe with a diameter of 20 nm. Observations were recorded both immediately adjacent to the grain boundaries and in the grain interiors. Symmetry breaking of the higher-order Laue zone (HOLZ) lines was observed adjacent to the boundaries after two and four passes but not in the grain interiors. Pattern simulation of the CBED patterns taken from the two- and four-pass samples adjacent to the boundaries revealed a homogeneous strain with compressive and shear components. The presence of these homogeneous strains demonstrates that the internal stresses associated with the deformation of aluminum at room temperature are localized in the close vicinity, to within similar to 20 nm, of the grain boundaries.

• 出版日期2011-11