Premium
On the multiple orientation relationship of the Mg/γ‐Mg 17 Al 12 precipitation system
Author(s) -
Liu Hongwei,
Liu Jiangwen,
Ouyang Liuzhang,
Luo Chengping
Publication year - 2012
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/s002188981200091x
Subject(s) - crystal twinning , precipitation , crystallography , orientation (vector space) , materials science , reflection (computer programming) , order (exchange) , chemistry , metallurgy , physics , mathematics , geometry , microstructure , finance , meteorology , computer science , programming language , economics
The six orientation relationships (ORs) found in the Mg/γ‐Mg 17 Al 12 precipitation system were summarized and systematically interpreted based on the atomic structure of the precipitate γ‐Mg 12 Al 17 and the invariant deformation element (IDE) model for diffusional phase transformations. It was found that the pseudo‐twinning relationship between the six ORs is a reflection of the pseudo‐twinning relationship between the close‐ or near‐close‐packing planes (), (11), (033), (411) and () in the precipitate γ‐Mg 12 Al 17 . As a result, the Pitsch–Schrader OR is the starting point for the other five ORs. Multiple morphologies, growth directions and habit planes could be rationally interpreted by the IDE model. This implies that a multiple orientation relationship between the variants of precipitates is favourable in order to minimize the gross energy of precipitation systems in which the matrix has a simple structure while the precipitate has a complicated structure, such as Mg/γ‐Mg 12 Al 17 , Mg/δ‐Zn 2 Zr 3 and Mg/η‐MgZn 2 couples.