A Soft Ceramic Ti3SiC2 with Microscale Plasticity at Room Temperature

Microscale plasticity of Ti3SiC2 was investigated by Vickers hardness indentation. The surface layer of the hardness indentations was removed by acid solution to observe microstructure beneath the indentations, where a large number of bending, delamination and kinking grains were found. These features suggest that Ti3SiC2 is able to consume microdamage around the indentations. Numerous basal plane dislocations and stacking faults lying in Ti3SiC2 grains or accumulating at grain boundaries were observed. The basal plane dislocations play an important role in the microscale plastic deformation. The plasticity and damage tolerance for Ti3SiC2 at room temperature should be attributed to multiple energy absorbing mechanisms: grains bending, delamination, kink-band formation, and the basal plane slip, etc.

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Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178732 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1120-1120

Author(s):

R. Haswell ◽

U. Bangert ◽

P. Charsley

Keyword(s):

Plastic Deformation ◽

Electron Microscope ◽

Room Temperature ◽

Stacking Faults ◽

The Other ◽

Ternary Alloys ◽

Dislocation Mobility ◽

Semiconducting Materials ◽

Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

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Expansion of Stacking Faults in 4H-SiC Epitaxial Layer under Laser Light Excitation during Room Temperature Photoluminescence Mapping

Materials Science Forum ◽

10.4028/www.scientific.net/msf.600-603.349 ◽

2008 ◽

Vol 600-603 ◽

pp. 349-352 ◽

Cited By ~ 6

Author(s):

Norihiro Hoshino ◽

Michio Tajima ◽

M. Naitoh ◽

Eiichi Okuno ◽

Shoichi Onda

Keyword(s):

Laser Beam ◽

Epitaxial Layer ◽

Basal Plane ◽

High Intensity ◽

Room Temperature ◽

Stacking Faults ◽

Scanning Laser ◽

Epitaxial Layers ◽

Dislocation Loops ◽

Room Temperature Photoluminescence

We investigated the expansion of single Shockley stacking faults (SSFs) in a 4H-SiC epitaxial layer under high-intensity scanning laser beam during room temperature photoluminescence mapping, which is similar to the degradation of bipolar pin diodes during forward current injection. In an epitaxial layer on an 8 off-axis (0001) substrate, the SSF-related intensity patterns induced by scanning high-intensity laser beam were classified into two types. The first one was a triangular pattern and the second a pattern which expanded in accordance with the motion of the scanning laser beam. The origins of the SSFs responsible for both patterns are presumably due to the preexisting basal plane dislocations and the dislocation-loops on the basal plane in the epitaxial layer, respectively. On the other hand, most of the SSF-expansion in on-axis (11 2 0) epitaxial layers were similar to the second type in the (0001) epitaxial layer. We, therefore, suggest that the dislocation-loops, which were located close to the surface, were dominant nucleation-sites of the SSFs in the (11 2 0) epitaxial layers.

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Influence of Temperature and Plastic Strain on Deformation Mechanisms and Kink Band Formation in Homogenized HfNbTaTiZr

Crystals ◽

10.3390/cryst11020081 ◽

2021 ◽

Vol 11 (2) ◽

pp. 81

Author(s):

Hans Chen ◽

Theresa Hanemann ◽

Sascha Seils ◽

Daniel Schliephake ◽

Aditya Srinivasan Tirunilai ◽

...

Keyword(s):

Plastic Deformation ◽

Plastic Strain ◽

Kink Band ◽

Deformation Mechanisms ◽

Large Temperature ◽

Plastic Strains ◽

Compression Tests ◽

Band Formation ◽

Influence Of Temperature ◽

Temperature Range

Due to its outstanding ductility over a large temperature range, equiatomic HfNbTaTiZr is well-suited for investigating the influence of temperature and plastic strain on deformation mechanisms in concentrated, body centered cubic solid solutions. For this purpose, compression tests in a temperature range from 77 up to 1073 K were performed and terminated at varying plastic strains for comparison of plastic deformation behavior. The microstructure and chemical homogeneity of a homogenized HfNbTaTiZr ingot were evaluated on different length scales. The compression tests reveal that test temperature significantly influences yield strength as well as work hardening behavior. Electron backscatter diffraction aids in shedding light on the acting deformation mechanisms at various temperatures and strains. It is revealed that kink band formation contributes to plastic deformation only in a certain temperature range. Additionally, the kink band misorientation angle distribution significantly differs at varying plastic strains.

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Mechanism of kink band formation in zinc single crystals

International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde) ◽

10.1515/ijmr-2020-7831 ◽

2021 ◽

Vol 112 (1) ◽

pp. 63-67

Author(s):

Krzysztof Pieła ◽

Andrzej Korbel

Keyword(s):

Single Crystals ◽

Basal Plane ◽

Kink Band ◽

Lattice Rotation ◽

Lattice Instability ◽

Band Formation

Abstract This paper is focused on the mechanism of kink band formation. In the general case, lattice rotation in a kink band may be realized by two sequentially activated simple elastic shears in nearly perpendicular planes. In the case of zinc crystals, compressed along (0001) plane at the temperature 523 K, the first shear may result from stress-induced temporary lattice instability (movement of atoms towards metastable positions in tetrahedric holes), while the second shear occurring along a temporary ‘new-positioned’ basal plane immediately ‘rebuilds’ the stable lattice.

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Defect clustering in GaN irradiated with O+ ions

Journal of Materials Research ◽

10.1557/jmr.2002.0427 ◽

2002 ◽

Vol 17 (11) ◽

pp. 2945-2952 ◽

Cited By ~ 40

Author(s):

C. M. Wang ◽

W. Jiang ◽

W. J. Weber ◽

L. E. Thomas

Keyword(s):

Point Defects ◽

Basal Plane ◽

Room Temperature ◽

Dynamic Recovery ◽

Stacking Faults ◽

Extended Defects ◽

Dislocation Loops ◽

Defect Clusters ◽

Transmission Electron ◽

High Resolution Tem

Transmission electron microscopy (TEM) was used to study microstructures formed in GaN irradiated with 600-keV O+ ions at room temperature. Three types of defect clusters were identified in the irradiated GaN: (i) basal-plane stacking faults with dimensions ranging from 5 to 30 nm, (ii) pyramidal dislocation loops, and (iii) local regions of highly disordered material. High-resolution TEM imaging clearly revealed that one type of the basal-plane stacking faults corresponded to insertion of one extra Ga–N basal plane in the otherwise perfect GaN lattice. The interpretation of these results indicated that interstitials of both Ga and N preferentially condensed on the basal plane to form a new layer of Ga–N under these irradiation conditions. The formation of these extended defects and their interactions with the point defects produced during irradiation contributed to a dramatic increase in the dynamic recovery of point defects in GaN at room temperature.

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Effect of Vanadium on Plastic Deformation in Llo TiAl Compound Alloys

MRS Proceedings ◽

10.1557/proc-133-687 ◽

1988 ◽

Vol 133 ◽

Cited By ~ 6

Author(s):

Sung H. Whang ◽

Yoo-Dong Hahn

Keyword(s):

Plastic Deformation ◽

Yield Stress ◽

Uniaxial Compression ◽

Fracture Stress ◽

Room Temperature ◽

Stacking Faults ◽

Aluminum Concentration ◽

Stress And Strain ◽

Thin Foils ◽

Miniature Specimens

ABSTRACTTernary Ti-Al-V (Llo) alloys containing vanadium up to 10 at.% and aluminum in the range of 50–55 at.% were prepared. Miniature specimens machined from these alloys were deformed in uniaxial compression at room temperature.The yield stress, and fracture stress and strain were determined with respect to vanadium and aluminum concentration. The deformed alloys were electropolished into thin foils and studied by TEM. In particular, the types of dislocations, stacking faults and twins in the Ti-Al-V alloys were investigated by TEM.

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