| Issue |
ESOMAT 2009
2009
|
|
|---|---|---|
| Article Number | 04007 | |
| Number of page(s) | 5 | |
| Section | Principles, Simulations, Materials: Advanced Materials | |
| DOI | https://doi.org/10.1051/esomat/200904007 | |
| Published online | 01 September 2009 | |
DOI: 10.1051/esomat/200904007
In-situ TEM straining of tetragonal martensite of Ni-Mn-Ga alloy
Yanling Ge1, Niva Zárubová1, 2, Zdeněk Dlabáček1, 2, Ilkka Aaltio1, Outi Söderberg1 and Simo-Pekka Hannula11 Department of Materials Science and Engineering, Helsinki University of Technology, P.O. Box 6200, FI-02015 TKK, Finlad
2 Institute of Physics, ASCR v.v.i., Na Slovance 2, 182 21 Prague 8, Czech Republic
yanling.ge@tkk.fi
Published online: 1 September 2009
Abstract
The in-situ straining of tetragonal martensite of Ni-Mn-Ga alloy was studied in a
transmission electron microscope (TEM) JEM 1200EX equipped with a double tilt straining stage.
The sample was analyzed before and after the straining experiments using the conventional as
well as high resolution TEM (Tecnai F20 G2 200kV FEG). Before straining, the martensitic
structure of the samples consisted of thermally induced self-accommodated multivariants.
During the in-situ straining, detwinning processes were recorded. The volume fraction of
the twin variants preferably oriented to the applied tensile force increased at the expense
of the less favorably oriented ones. The movement of the twin boundaries was followed in detail.
The analysis performed after straining suggested that the detwinning processes occurred by
movement of twinning dislocations. The interface between two twinned bands acted as a nucleation
source for emitting the twinning dislocations.
© Owned by the authors, published by EDP Sciences 2009