scholarly journals Localized Deformation and Fracture Behaviors in InP Single Crystals by Indentation

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 611 ◽  
Author(s):  
Yi-Jui Chiu ◽  
Sheng-Rui Jian ◽  
Ti-Ju Liu ◽  
Phuoc Le ◽  
Jenh-Yih Juang
Keyword(s):  
Single Crystals ◽  
Dislocation Nucleation ◽  
Deformation Mechanisms ◽  
Vickers Indentation ◽  
Localized Deformation ◽  
Cross Sectional ◽  
Fracture Patterns ◽  
Transmission Electron ◽  
Deformation And Fracture ◽  
Fracture Behaviors

The indentation-induced deformation mechanisms in InP(100) single crystals were investigated by using nanoindentation and cross-sectional transmission electron microscopy (XTEM) techniques. The results indicated that there were multiple “pop-in” events randomly distributed in the loading curves, which were conceived to arise primarily from the dislocation nucleation and propagation activities. An energetic estimation on the number of nanoindentation-induced dislocations associated with pop-in effects is discussed. Furthermore, the fracture patterns were performed by Vickers indentation. The fracture toughness and the fracture energy of InP(100) single crystals were calculated to be around 1.2 MPa·m1/2 and 14.1 J/m2, respectively.

In Situ High Voltage Electron Microscopy Observations of Deformation and Fracture in Multilayered Materials

1995 ◽  
Vol 404 ◽  
Author(s):  
M. A. Wall ◽  
T. W. Barbee ◽  
T. P. Weihs
Keyword(s):  
Crack Nucleation ◽  
Free Standing ◽  
Cross Sectional ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Transmission Electron ◽  
Deformation And Fracture ◽  
Gauge Section ◽  
Multilayered Materials

AbstractA novel, in situ transmission electron microcopy technique for the direct observation of deformation and fracture in multilayered materials oriented in cross-section is reviewed. Cross-sectional tensile specimens were prepared from thick, free-standing, Cu/Zr and Al/Ti multilayered foils. These tensile specimens contain a micro-gauge section, thus predetermining the location at which dislocation activity and crack nucleation and growth can be observed at high magnifications in the transmission electron microscope. The results from these experiments are unique and cannot be realized by any other technique. These observations will aid us in our understanding of the micromechanisms of deformation and fracture in multilayered materials.

Deformation and fracture behaviors of [011]-poled Pb(Zn1/3Nb2/3)O3–7%PbTiO3 single crystals

2008 ◽  
Vol 498 (1-2) ◽  
pp. 457-463 ◽  
Author(s):  
Kaiyang Zeng ◽  
Yilin Ng ◽  
Lu Shen ◽  
K.K. Rajan ◽  
Leong-Chew Lim
Keyword(s):  
Single Crystals ◽  
Deformation And Fracture ◽  
Fracture Behaviors

Damage Evolution in Xe-Ion Irradiated Rutile (TiO2) Single Crystals

1998 ◽  
Vol 540 ◽  
Author(s):  
Fuxin Li ◽  
Ping Lu ◽  
Kurt E. Sickafus ◽  
Caleb R. Evans ◽  
Michael Nastasi
Keyword(s):  
Single Crystals ◽  
Ion Irradiation ◽  
Amorphous Layer ◽  
High Concentration ◽  
Cross Sectional ◽  
Defect Migration ◽  
Ion Channeling ◽  
Projected Range ◽  
Transmission Electron ◽  
Nucleation Sites

AbstractRutile (TiO2) single crystals with (110) orientation were irradiated with 360 keV Xe2+ ions at 300K to fluences ranging from 2×1019 to 1×1020 Xe/m2. Irradiated samples were analyzed using: (1) Rutherford backscattering spectroscopy combined with ion channeling analysis (RBS/C); and (2) cross-sectional transmission electron microscopy (XTEM). Upon irradiation to a fluence of 2×1O19 Xe/m2, the sample thickness penetrated by the implanted ions was observed to consist of three distinct layers: (1) a defect-free layer at the surface (thickness about 12 nm) exhibiting good crystallinity; (2) a second layer with a low density of relatively large- sized defects; and (3) a third layer consisting of a high concentration of small defects. After the fluence was increased to 7×1019 Xe/m2, a buried amorphous layer was visible by XTEM. The thickness of the amorphous layer was found to increase with increasing Xe ion fluence. The location of this buried amorphous layer was found to coincide with the measured peak in the Xe concentration (measured by RBS/C), rather than with the theoretical maXimum in the displacement damage profile. This observation suggests the implanted Xe ions may serve as nucleation sites for the amorphization transformation. The total thickness of the damaged microstructure due to ion irradiation was always found to be much greater than the projected range of the Xe ions. This is likely due to point defect migration under the high stresses induced by ion implantation.

Observations of nanoindents via cross-sectional transmission electron microscopy: a survey of deformation mechanisms

2005 ◽  
Vol 461 (2060) ◽  
pp. 2521-2543 ◽  
Author(s):  
S.J Lloyd ◽  
A Castellero ◽  
F Giuliani ◽  
Y Long ◽  
K.K McLaughlin ◽  
...  
Keyword(s):  
Cross Sections ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Deformation Behaviour ◽  
Shear Bands ◽  
Three Dimensional ◽  
Deformation Mechanisms ◽  
Lattice Rotation ◽  
Cross Sectional ◽  
Transmission Electron

Examination of cross-sections of nanoindents with the transmission electron microscope has recently become feasible owing to the development of focused ion beam milling of site-specific electron transparent foils. Here, we discuss the development of this technique for the examination of nanoindents and survey the deformation behaviour in a range of single crystal materials with differing resistances to dislocation flow. The principal deformation modes we discuss, in addition to dislocation flow, are phase transformation (silicon and germanium), twinning (gallium arsenide and germanium at 400 °C), lattice rotations (spinel), shear (spinel), lattice rotations (copper) and lattice rotations and densification (TiN/NbN multilayers). The magnitude of the lattice rotation, about the normal to the foil, was measured at different positions under the indents. Indents in a partially recrystallized metallic glass Mg 66 Ni 20 Nd 14 were also examined. In this case a low-density porous region was formed at the indent tip and evidence of shear bands was also found. Further understanding of indentation deformation will be possible with three-dimensional characterization coupled with modelling which takes account of the variety of competing deformation mechanisms that can occur in addition to dislocation glide. Mapping the lattice rotations will be a particularly useful way to evaluate models of the deformation process.

Cross-sectional observation on the indentation of [001] silicon

1999 ◽  
Vol 14 (6) ◽  
pp. 2399-2401 ◽  
Author(s):  
Y. Q. Wu ◽  
G. Y. Shi ◽  
Y. B. Xu
Keyword(s):  
Electron Microscope ◽  
Ambient Temperature ◽  
Amorphous Silicon ◽  
Transmission Electron Microscope ◽  
Indentation Depth ◽  
Hydrostatic Stress ◽  
Surface Shape ◽  
Vickers Indentation ◽  
Cross Sectional ◽  
Transmission Electron

A transmission electron microscope (TEM) micrograph of cross-sectionally viewed Vickers indentation made on the surface of (001) silicon at ambient temperature was obtained. The picture clearly reveals a triangle area, pointing downward and having nondiffraction-contrast, left after unloading, which further confirms the amorphized range induced by indentation in silicon. Analysis of the picture directly manifests a significant recovery of indentation depth. Surface shape and range of the amorphous silicon region do not coincide with that of the indenter and the corresponding distribution pattern of hydrostatic stress beneath indentation predicted by elastoplastic theory, respectively. It seems that the amorphization could not be attributed to the result of hydrostatic stress alone.

A Field Emission System For Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 298-299
Author(s):  
Michel Troyonal ◽  
Huei Pei Kuoal ◽  
Benjamin M. Siegelal
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Optical System ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Electron Optical System ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Emission System

A field emission system for our experimental ultra high vacuum electron microscope has been designed, constructed and tested. The electron optical system is based on the prototype whose performance has already been reported. A cross-sectional schematic illustrating the field emission source, preaccelerator lens and accelerator is given in Fig. 1. This field emission system is designed to be used with an electron microscope operated at 100-150kV in the conventional transmission mode. The electron optical system used to control the imaging of the field emission beam on the specimen consists of a weak condenser lens and the pre-field of a strong objective lens. The pre-accelerator lens is an einzel lens and is operated together with the accelerator in the constant angular magnification mode (CAM).

A tilting high temperature gas reaction chamber for the JEM 7A T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 70-71
Author(s):  
Brian L. Rhoades
Keyword(s):  
Cross Section ◽  
Reaction Chamber ◽  
Objective Lens ◽  
Reduced Cross Section ◽  
Cross Sectional ◽  
Structural Investigations ◽  
Transmission Electron ◽  
Dynamic Experiments ◽  
Successful Design ◽  
Thermocouple Junction

A gas reaction chamber has been designed and constructed for the JEM 7A transmission electron microscope which is based on a notably successful design by Hashimoto et. al. but which provides specimen tilting facilities of ± 15° aboutany axis in the plane of the specimen.It has been difficult to provide tilting facilities on environmental chambers for 100 kV microscopes owing to the fundamental lack of available space within the objective lens and the scope of structural investigations possible during dynamic experiments has been limited with previous specimen chambers not possessing this facility.A cross sectional diagram of the specimen chamber is shown in figure 1. The specimen is placed on a platinum ribbon which is mounted on a mica ring of the type shown in figure 2. The ribbon is heated by direct current, and a thermocouple junction spot welded to the section of the ribbon of reduced cross section enables temperature measurement at the point where localised heating occurs.

Precipitation of NiHfsi phase in NiAl single crystals containing Hf

1995 ◽  
Vol 53 ◽  
pp. 532-533
Author(s):  
A. Garg ◽  
R. D. Noebe ◽  
R. Darolia
Keyword(s):  
High Temperature ◽  
Single Crystals ◽  
High Temperature Strength ◽  
Bridgman Technique ◽  
Shell Mold ◽  
Third Phase ◽  
Unknown Phase ◽  
Transmission Electron ◽  
Two Phases ◽  
Nial Matrix

Small additions of Hf to NiAl produce a significant increase in the high-temperature strength of single crystals. Hf has a very limited solubility in NiAl and in the presence of Si, results in a high density of G-phase (Ni16Hf6Si7) cuboidal precipitates and some G-platelets in a NiAl matrix. These precipitates have a F.C.C structure and nucleate on {100}NiAl planes with almost perfect coherency and a cube-on-cube orientation-relationship (O.R.). However, G-phase is metastable and after prolonged aging at high temperature dissolves at the expense of a more stable Heusler (β'-Ni2AlHf) phase. In addition to these two phases, a third phase was shown to be present in a NiAl-0.3at. % Hf alloy, but was not previously identified (Fig. 4 of ref. 2 ). In this work, we report the morphology, crystal-structure, O.R., and stability of this unknown phase, which were determined using conventional and analytical transmission electron microscopy (TEM).Single crystals of NiAl containing 0.5at. % Hf were grown by a Bridgman technique. Chemical analysis indicated that these crystals also contained Si, which was not an intentional alloying addition but was picked up from the shell mold during directional solidification.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

Transmission Electron Microscopy Studies of Aluminum Oxidation

1985 ◽  
Vol 43 ◽  
pp. 268-269
Author(s):  
J.Y. Lee
Keyword(s):  
Nucleation And Growth ◽  
Ion Milling ◽  
Cross Sectional ◽  
Polycrystalline Aluminum ◽  
Axis Orientation ◽  
Temperature Oxidation ◽  
Aluminum Oxidation ◽  
Transmission Electron ◽  
High Resolution Images ◽  
Argon Ion

In the oxidation of metals and alloys, microstructural features at the atomic level play an important role in the nucleation and growth of the oxide, but little is known about the atomic mechanisms of high temperature oxidation. The present paper describes current progress on crystallographic aspects of aluminum oxidation. The 99.999% pure, polycrystalline aluminum was chemically polished and oxidized in 1 atm air at either 550°C or 600°C for times from 0.5 hr to 4 weeks. Cross-sectional specimens were prepared by forming a sandwich with epoxy, followed by mechanical polishing and then argon ion milling. High resolution images were recorded in a <110>oxide zone-axis orientation with a JE0L JEM 200CX microscope operated at 200 keV.

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