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Electron backscatter diffraction study of variant selection during ordering phase transformation in L1 0 ‐type red gold alloy
Author(s) -
Larcher Margaux N. D.,
Cayron Cyril,
Blatter Andreas,
Soulignac Raphaëlle,
Logé Roland E.
Publication year - 2019
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/s1600576719011890
Subject(s) - electron backscatter diffraction , tetragonal crystal system , materials science , diffusionless transformation , diffraction , lattice (music) , condensed matter physics , electron diffraction , alloy , distortion (music) , crystallography , martensite , optics , microstructure , physics , chemistry , metallurgy , crystal structure , amplifier , optoelectronics , cmos , acoustics
A shape‐memory effect is known to appear in red gold alloys with compositions close to Au–Cu. The aim of this paper is to study by electron backscatter diffraction (EBSD) the variant selection in the A1 → L1 0 transformation occurring under stress, in bending conditions. The L1 0 domains are successfully identified by this technique despite the c / a ratio being close to unity. The orientation relationship between the cubic and tetragonal phases is determined by a careful analysis of the EBSD data. The distortion of the lattice for each variant is then modelled and calculated from the experimental orientations. The mechanical work associated with the transformation is computed from the lattice distortion by neglecting the obliquity. Finally, the distribution of this mechanical work is compared with the case of a uniform distribution of all variants, in order to evaluate the extent of variant selection. The maximal work criterion, often used for martensitic transformations, enabled quantification of the variant selection phenomenon.