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Electron diffraction characterization of a new metastable Al 2 Cu phase in an Al–Cu friction stir weld
Author(s) -
Ji Gang,
Morniroli JeanPaul
Publication year - 2013
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889813001635
Subject(s) - tetragonal crystal system , orthorhombic crystal system , transmission electron microscopy , electron diffraction , crystallography , materials science , metastability , electron backscatter diffraction , phase (matter) , reflection high energy electron diffraction , diffraction , selected area diffraction , chemistry , crystal structure , microstructure , optics , nanotechnology , physics , organic chemistry
The space group of a new metastable orthorhombic Al 2 Cu phase, located in the Al‐rich interfacial region of an Al–Cu friction stir weld, was unambiguously identified as Ic 2 m by a recently developed systematic method combining precession electron diffraction and convergent‐beam electron diffraction. This metastable phase has the same tetragonal lattice as its stable θ‐Al 2 Cu counterpart (tetragonal, I 4/ mcm , No. 140). The tetragonal‐to‐orthorhombic symmetry lowering is due to slight modifications of the atomic positions in the unit cell. This metastable phase can be transformed into the stable θ‐Al 2 Cu phase by in situ irradiation within the transmission electron microscope.