The stacking fault energy in the vicinity of a coherent twin boundary

Electron microscopy has made a great success in the identification of lattice defects. Convergent-beam electron diffraction (CBED) also allows us to identify them and CBED gives more information about lattice defects than the electron- microscope-image method. Lattice defects are divided into two basic types. One causes a phase shift at the defect and the other an angular change. The stacking fault is a typical example of the former type and the coherent twin boundary, of the latter type. The dislocation can be treated as an extension of the former type. CBED can determine the displacement vector of a stacking fault, the Burgers vector of a dislocation and the orientation difference at a coherent twin boundary reliably and easily. We will explain the methods to determine them using examples. STACKING FAULTS : Rocking curves obtained from a stacking fault are different from those of a perfect region in a manner characteristic of the displacement between two crystals at the fault.

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Size-dependent stability of stacking fault tetrahedron in coherent twin boundary bicrystal: Comparisons among Al, Ni, Cu and Ag

Computational Materials Science ◽

10.1016/j.commatsci.2018.08.049 ◽

2018 ◽

Vol 155 ◽

pp. 256-265 ◽

Cited By ~ 3

Author(s):

Lianping Wu ◽

Wenshan Yu ◽

Shuling Hu ◽

Shengping Shen

Keyword(s):

Twin Boundary ◽

Stacking Fault ◽

Coherent Twin Boundary ◽

Size Dependent ◽

Stacking Fault Tetrahedron

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On effects of non-systematic reflections on weak-beam images of partial dislocations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087756 ◽

1991 ◽

Vol 49 ◽

pp. 688-689

Author(s):

K. Z. Botros ◽

S. S. Sheinin

Keyword(s):

High Precision ◽

Stacking Fault ◽

Important Application ◽

Stacking Fault Energy ◽

Sharp Peak ◽

Weak Beam ◽

Partial Dislocations ◽

Deviation Parameter ◽

Beam Diffraction

The main features of weak beam images of dislocations were first described by Cockayne et al. using calculations of intensity profiles based on the kinematical and two beam dynamical theories. The feature of weak beam images which is of particular interest in this investigation is that intensity profiles exhibit a sharp peak located at a position very close to the position of the dislocation in the crystal. This property of weak beam images of dislocations has an important application in the determination of stacking fault energy of crystals. This can easily be done since the separation of the partial dislocations bounding a stacking fault ribbon can be measured with high precision, assuming of course that the weak beam relationship between the positions of the image and the dislocation is valid. In order to carry out measurements such as these in practice the specimen must be tilted to "good" weak beam diffraction conditions, which implies utilizing high values of the deviation parameter Sg.

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Structural features and strength behavior of TRIP/TWIP steels

Perspektivnye Materialy ◽

10.30791/1028-978x-2020-9-5-18 ◽

2020 ◽

pp. 5-18

Author(s):

D. V. Prosvirnin ◽

◽

M. S. Larionov ◽

S. V. Pivovarchik ◽

A. G. Kolmakov ◽

...

Keyword(s):

Mechanical Properties ◽

Chemical Composition ◽

Thermomechanical Processing ◽

Maximum Load ◽

Structural Features ◽

Stacking Fault ◽

Stacking Fault Energy ◽

Structural And Functional Properties ◽

Twip Steels ◽

The Creation

A review of the literature data on the structural features of TRIP / TWIP steels, their relationship with mechanical properties and the relationship of strength parameters under static and cyclic loading was carried out. It is shown that the level of mechanical properties of such steels is determined by the chemical composition and processing technology (thermal and thermomechanical processing, hot and cold pressure treatment), aimed at achieving a favorable phase composition. At the atomic level, the most important factor is stacking fault energy, the level of which will be decisive in the formation of austenite twins and / or the formation of strain martensite. By selecting the chemical composition, it is possible to set the stacking fault energy corresponding to the necessary mechanical characteristics. In the case of cyclic loads, an important role is played by the strain rate and the maximum load during testing. So at high loading rates and a load approaching the yield strength under tension, the intensity of the twinning processes and the formation of martensite increases. It is shown that one of the relevant ways to further increase of the structural and functional properties of TRIP and TWIP steels is the creation of composite materials on their basis. At present, surface modification and coating, especially by ion-vacuum methods, can be considered the most promising direction for the creation of such composites.

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