Stacking Faults and Stacking Fault Energy of Hexagonal Barium Titanate

2006 ◽  
Vol 89 (12) ◽  
pp. 3778-3787 ◽  
Author(s):  
Yu-Chuan Wu ◽  
Sea-Fue Wang ◽  
Hong-Yang Lu
Keyword(s):  
Barium Titanate ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Stacking Fault Energy

Dislocations and stacking faults in stainless steel

1957 ◽  
Vol 240 (1223) ◽  
pp. 524-538 ◽  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Grain Boundaries ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Thin Sections ◽  
Partial Dislocations ◽  
Transmission Electron

Further experiments by transmission electron microscopy on thin sections of stainless steel deformed by small amounts have enabled extended dislocations to be observed directly. The arrangement and motion of whole and partial dislocations have been followed in detail. Many of the dislocations are found to have piled up against grain boundaries. Other observations include the formation of wide stacking faults, the interaction of dislocations with twin boundaries, and the formation of dislocations at thin edges of the foils. An estimate is made of the stacking-fault energy from a consideration of the stresses present, and the properties of the dislocations are found to be in agreement with those expected from a metal of low stacking-fault energy.

Stacking Faults in Crystals

1968 ◽  
Vol 26 ◽  
pp. 250-251
Author(s):  
P. C. J. Gallagher
Keyword(s):  
Stacking Faults ◽  
Elastic Equilibrium ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Major Influence ◽  
Face Centered Cubic ◽  
Degree Of Dissociation ◽  
Partial Dislocations ◽  
Layer Structures ◽  
Face Centered

Stacking faults are an important substructural feature of many materials, and have been widely studied in layer structures (e.g. talc) and in crystals with hexagonal and face centered cubic structure. Particular emphasis has been placed on the study of faulted defects in f.c.c. alloys, since the width of the band of fault between dissociated partial dislocations has a major influence on mechanical properties.Under conditions of elastic equilibrium the degree of dissociation reflects the balance of the repulsive force between the partials bounding the fault, and the attractive force associated with the need to minimize the energy arising from the misfits in stacking sequence. Examples of two of the faulted defects which can be used to determine this stacking fault energy, Υ, are shown in Fig. 1. Intrinsically faulted extended nodes (as at A) have been widely used to determine Υ, and examples will be shown in several Cu and Ag base alloys of differing stacking fault energy. The defect at B contains both extrinsic and intrinsic faulting, and readily enables determination of both extrinsic and intrinsic fault energies.

Effects of Stacking Faults on High Temperature Creep Behavior in Mg-Y-Zn Based Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 1602-1607 ◽  
Author(s):  
Mayumi Suzuki ◽  
Kouichi Maruyama
Keyword(s):  
Activation Energy ◽  
Creep Behavior ◽  
Stacking Faults ◽  
Dislocation Motion ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Ternary Alloys ◽  
Solute Content ◽  
Planar Defects ◽  
Multiple Addition

Compressive creep behavior of hot-rolled (40%) Mg-Y and Mg-Y-Zn alloys are investigated at 480 ~ 650 K. Creep strength is substantially improved by the simultaneous addition of yttrium and zinc. The minimum creep rate of Mg-0.9mol%Y-0.04mol%Zn (WZ301) alloy decreases to 1/10 lower than that of Mg-1.1mol%Y (W4) alloy at 650 K. Activation energy for creep in W4 and WZ301 alloys are more than 200 kJ/mol at the temperature range of 480 ~ 550 K. These values are higher than the activation energy for self-diffusion coefficient in magnesium (135 kJ/mol). Many stacking faults (planar defects, PDs) are only observed on the basal planes of the matrix in Mg-Y-Zn ternary alloys. Stacking fault energy is considered to decrease by the multiple-addition of yttrium and zinc. The size and density of these planar defects depend on solute content, aging condition. TEM observation has been revealed that the decreasing of the stacking fault energy affects the distribution of dislocations during creep. Many a-dislocations on basal planes are extended significantly. Dislocation motion is restricted significantly by both of these two types of stacking faults (planar type and extended dislocations).

scholarly journals Stacking Fault Energy of Si Nanocrystals Embedded in SiO2

2011 ◽  
Vol 2011 ◽  
pp. 1-3 ◽  
Author(s):  
Y. Q. Wang ◽  
W. S. Liang ◽  
G. G. Ross
Keyword(s):  
Stacking Faults ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
High Temperature Annealing ◽  
Hrtem Image ◽  
Burgers Vector ◽  
Transmission Electron ◽  
Hrtem Observation ◽  
Si Nanocrystals ◽  
Perfect Dislocation

Si nanocrystals (Si nc) were produced by the implantation of Si+ into a SiO2 film on (100) Si, followed by high-temperature annealing. High-resolution transmission electron microscopy (HRTEM) observation has shown that a perfect dislocation (Burgers vector b=(1/2)〈110〉) can dissociate into two Shockley partials (Burgers vector b=(1/6)〈112〉) bounding a strip of stacking faults (SFs). The width of the SFs has been determined from the HRTEM image, and the stacking fault energy for Si nc has been calculated. The stacking fault energy for Si nc is compared with that for bulk Si, and the formation probability of defects in Si nc is also discussed. The results will shed a light on the dissociation of dislocations in nanoparticles.

Stacking fault energy in austenitic steels determined by usingin situX-ray diffraction during bending

2014 ◽  
Vol 47 (3) ◽  
pp. 936-947 ◽  
Author(s):  
D. Rafaja ◽  
C. Krbetschek ◽  
C. Ullrich ◽  
S. Martin
Keyword(s):  
Critical Stress ◽  
Partial Dislocation ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Austenitic Steels ◽  
X Ray Diffraction ◽  
X Ray ◽  
Partial Dislocations

A method is presented which determines the stacking fault energy in face-centred cubic materials from the critical stress that is inducedviasample bending in the early stages of plastic deformation. The critical stress is gauged byin situX-ray diffraction. This method utilizes the results of Byun's consideration of the stress dependence of the partial dislocation separation [Byun (2003).Acta Mater.51, 3063–3071]. Byun showed that the separation distance of the partial dislocations increases rapidly when the critical stress is reached and that the critical stress needed for the rapid separation of the partial dislocations is directly proportional to the stacking fault energy. In the approach presented here, the partial dislocation separation and the corresponding triggering stress are monitored by usingin situX-ray diffraction during sample bending. Furthermore, thein situX-ray diffraction measurement checks the possible interactions between stacking faults present on equivalent lattice planes and the interactions of the stacking faults with other microstructure defects. The capability of the proposed method was tested on highly alloyed austenitic steels containing chromium (∼16 wt%), manganese (∼7 wt%) and nickel as the main alloying elements. For the steels containing 5.9 and 3.7 wt% Ni, stacking fault energies of 17.5 ± 1.4 and 8.1 ± 0.9 mJ m−2were obtained, respectively.

Stacking Fault Energy Calculations in 6H- and 15R-SiC

1994 ◽  
Vol 339 ◽  
Author(s):  
F. R. Chien ◽  
S. R. Nutt ◽  
W. S. Yoo
Keyword(s):  
Ising Model ◽  
Ab Initio ◽  
Single Crystals ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Energy Calculations ◽  
Stacking Fault Energies

ABSTRACTAs-grown SiC single crystals and as-deposited SiC epilayers often exhibit stacking faults. The most probable fault configurations that occur in 6H- or 15R-SiC crystals are deduced from calculations of the stacking fault energies using a modified Ising model with the Ising parameters taken from earlier ab initio calculations. In this study, experimental TEM observations reveal stacking fault configurations in 6H- and 15R-SiC, and the observed configurations are compared with calculated stacking fault energies.

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

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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