scholarly journals Low-temperature rheology of calcite

2019 ◽  
Vol 221 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Michael K Sly ◽  
Arashdeep S Thind ◽  
Rohan Mishra ◽  
Katharine M Flores ◽  
Philip Skemer
Keyword(s):  
Low Temperature ◽  
Yield Stress ◽  
Low Temperatures ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Polycrystalline Sample ◽  
Small Scale ◽  
Indentation Hardness ◽  
Micropillar Compression ◽  
Flow Laws

SUMMARY Low-temperature plastic rheology of calcite plays a significant role in the dynamics of Earth's crust. However, it is technically challenging to study plastic rheology at low temperatures because of the high confining pressures required to inhibit fracturing. Micromechanical tests, such as nanoindentation and micropillar compression, can provide insight into plastic rheology under these conditions because, due to the small scale, plastic deformation can be achieved at low temperatures without the need for secondary confinement. In this study, nanoindentation and micropillar compression experiments were performed on oriented grains within a polycrystalline sample of Carrara marble at temperatures ranging from 23 to 175 °C, using a nanoindenter. Indentation hardness is acquired directly from nanoindentation experiments. These data are then used to calculate yield stress as a function of temperature using numerical approaches that model the stress state under the indenter. Indentation data are complemented by uniaxial micropillar compression experiments. Cylindrical micropillars ∼1 and ∼3 μm in diameter were fabricated using a focused ion beam-based micromachining technique. Yield stress in micropillar experiments is determined directly from the applied load and micropillar dimensions. Mechanical data are fit to constitutive flow laws for low-temperature plasticity and compared to extrapolations of similar flow laws from high-temperature experiments. This study also considered the effects of crystallographic orientation on yield stress in calcite. Although there is a clear orientation dependence to plastic yielding, this effect is relatively small in comparison to the influence of temperature.

Mechanical Properties of Electroplated Copper Thin Films

1999 ◽  
Vol 594 ◽  
Author(s):  
R. Spolenak ◽  
C. A. Volkert ◽  
K. Takahashi ◽  
S. Fiorillo ◽  
J. Miner ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Grain Size ◽  
Film Thickness ◽  
Yield Stress ◽  
Laser Scanning ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Cu Films ◽  
Electroplated Copper

AbstractIt is well known that the mechanical properties of thin films depend critically on film thickness However, the contributions from film thickness and grain size are difficult to separate, because they typically scale with each other. In one study by Venkatraman and Bravman, Al films, which were thinned using anodic oxidation to reduce film thickness without changing grain size, showed a clear increase in yield stress with decreasing film thickness.We have performed a similar study on both electroplated and sputtered Cu films by using chemical-mechanical polishing (CMP) to reduce the film thickness without changing the grain size. Stress-temperature curves were measured for both the electroplated and sputtered Cu films with thicknesses between 0.1 and 1.8 microns using a laser scanning wafer curvature technique. The yield stress at room temperature was found to increase with decreasing film thickness for both sets of samples. The sputtered films, however, showed higher yield stresses in comparison to the electroplated films. Most of these differences can be attributed to the different microstructures of the films, which were determined by focused ion beam (FIB) microscopy and x-ray diffraction.

scholarly journals Ion Irradiation-Induced Microstructural Evolution of Ni–Mo–Cr Low Alloy Steels

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2268
Author(s):  
Hongying Sun ◽  
Penghui Lei ◽  
Guang Ran ◽  
Hui Wang ◽  
Jiyun Zheng ◽  
...  
Keyword(s):  
Irradiation Dose ◽  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Strength ◽  
Positron Annihilation Spectroscopy ◽  
Small Scale ◽  
Low Alloy Steels ◽  
Dislocation Loops ◽  
S Parameter

As leading candidates of sheet steels for advanced nuclear reactors, three types of Ni–Mo–Cr high-strength low alloy (HSLA) steels named as CNST1, CNST2 and CNSS3 were irradiated by 400 keV Fe+ with peak fluence to 1.4 × 1014, 3.5 × 1014 and 7.0 × 1014 ions/cm2, respectively. The distribution and morphology of the defects induced by the sample preparation method and Fe+ irradiation dose were investigated by transmission electron microscopy (TEM) and positron-annihilation spectroscopy (PAS). TEM samples were prepared with two methods, i.e., a focused ion beam (FIB) technique and the electroplating and twin-jet electropolishing (ETE) method. Point defects and dislocation loops were observed in CNST1, CNST2 and CNSS3 samples prepared via FIB. On the other hand, samples prepared via the ETE method revealed that a smaller number of defects was observed in CNST1, CNST2 and almost no defects were observed in CNST3. It is indicated that artifact defects could be introduced by FIB preparation. The PAS S-W plots showed that the existence of two types of defects after ion implantation included small-scale defects such as vacancies, vacancy clusters, dislocation loops and large-sized defects. The S parameter of irradiated steels showed a clear saturation in PAS response with increasing Fe+ dose. At the same irradiation dose, higher values of the S-parameter were achieved in CNST1 and CNST2 samples when compared to that in CNSS3 samples. The mechanism and evolution behavior of irradiation-induced defects were analyzed and discussed.

Modification of structure and optical property of ZnO nanowires by Ga ion beam

2009 ◽  
Vol 1201 ◽  
Author(s):  
Yao Cheng ◽  
Yao Liang ◽  
Ming Lei ◽  
Siu Kong Hark ◽  
Ning Wang
Keyword(s):  
Optical Property ◽  
Low Temperatures ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Green Emission ◽  
Zno Nanowires ◽  
Crystal Quality ◽  
Spectroscopy Study ◽  
Doped Zno ◽  
Ga Doping

AbstractBased on the focused ion beam (FIB) technology, we have prepared ZnO nanowires containing periodic nano-sized structures by an ultra thin Ga ion beam. ZnO nanowires can keep a good crystal quality after Ga ion bombardment. The cathodoluminescence (CL) spectroscopy study of the Ga-doped ZnO nanowires at low temperatures shows that the Ga doping effect can largely suppress the green emission that may mainly originate from the defects on the surfaces of ZnO nanowires.

scholarly journals Fusion of Mitochondria to 3-D Networks, Autophagy and Increased Organelle Contacts are Important Subcellular Hallmarks during Cold Stress in Plants

2020 ◽  
Vol 21 (22) ◽  
pp. 8753
Author(s):  
Philip Steiner ◽  
Othmar Buchner ◽  
Ancuela Andosch ◽  
Gerhard Wanner ◽  
Gilbert Neuner ◽  
...  
Keyword(s):  
Low Temperature ◽  
Temperature Stress ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Low Temperature Stress ◽  
Freezing Stress ◽  
Electron Microscopic ◽  
Natural Habitats ◽  
Ultrastructural Alterations ◽  
Micrasterias Denticulata

Low temperature stress has a severe impact on the distribution, physiology, and survival of plants in their natural habitats. While numerous studies have focused on the physiological and molecular adjustments to low temperatures, this study provides evidence that cold induced physiological responses coincide with distinct ultrastructural alterations. Three plants from different evolutionary levels and habitats were investigated: The freshwater alga Micrasterias denticulata, the aquatic plant Lemna sp., and the nival plant Ranunculus glacialis. Ultrastructural alterations during low temperature stress were determined by the employment of 2-D transmission electron microscopy and 3-D reconstructions from focused ion beam–scanning electron microscopic series. With decreasing temperatures, increasing numbers of organelle contacts and particularly the fusion of mitochondria to 3-dimensional networks were observed. We assume that the increase or at least maintenance of respiration during low temperature stress is likely to be based on these mitochondrial interconnections. Moreover, it is shown that autophagy and degeneration processes accompany freezing stress in Lemna and R. glacialis. This might be an essential mechanism to recycle damaged cytoplasmic constituents to maintain the cellular metabolism during freezing stress.

Small Scale Plastic Yielding of Mg Alloys Assessed with Nanoindentation

2020 ◽  
Vol 405 ◽  
pp. 339-344
Author(s):  
Jiří Němeček ◽  
Jan Maňák ◽  
Jiří Němeček
Keyword(s):  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Az31 Alloy ◽  
Small Scale ◽  
Spherical Indentation ◽  
Plastic Properties ◽  
Indentation Tests ◽  
Order Of Magnitude ◽  
Volume Characteristics

The paper investigates deformations and plastic properties received from different material volumes and tests of magnesium samples. Small volume characteristics gained on single Mg crystals are compared to polycrystalline AZ31 alloy. Results of tests employing nanoindentation, focused ion beam milling and electron backscatter diffraction techniques are presented. Large differences were found between micro-beam testing and spherical indentation tests having the volume one order of magnitude apart. The plastic strength scaling factor was found 1.7 for the studied grain configurations and volumes.

Focused Ion Beam Implantation of GaAs-GaAlAs Quantum Well Structures

1988 ◽  
Vol 126 ◽  
Author(s):  
P. M. Petroff ◽  
Xueyu Qian ◽  
Per Olof Holtz ◽  
R. J. Simes ◽  
J. H. English ◽  
...  
Keyword(s):  
Low Temperature ◽  
Quantum Well ◽  
Focused Ion Beam ◽  
Quantum Wires ◽  
Ion Beam ◽  
Damage Distribution ◽  
Quantum Well Structures ◽  
Ion Beam Implantation ◽  
Dose Effects

ABSTRACTThe effects of Implantation Enhanced Interdiffusion (IEI) in GaAs-GaAlAs quantum well structures are investigated. A Focused Ion Beam (FIB) source is used to implant narrow lines (500Å wide) with Ga+ ions. IEI in these structures is characterized by low temperature Cathodoluminescence. The dose effects and annealing kinetics dependence on IEI are presented. An unusual damage distribution which produces IEI deep below the surface is observed for the case of FIB implant. The possible origins of this effect and the limits of IEI for processing quantum wires and boxes are discussed.

Anomalies in the temperature dependence of the yield stress of metals at low temperatures

1983 ◽  
Vol 61 (11) ◽  
pp. 1528-1530 ◽  
Author(s):  
S. M. Raza
Keyword(s):  
Low Temperature ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Low Temperatures ◽  
Structural Changes ◽  
Zero Point ◽  
Quantum Effects ◽  
Enhancement Effect ◽  
Polycrystalline Nickel ◽  
Creep Equation

Yield stress "anomalies" have been studied in polycrystalline nickel at low temperatures. Both quantum effects and structural changes below 0.1–0.2 of the Debye temperature contribute to low-temperature anomalies in the temperature dependence of the yield stress. The anomalies appear to be basically a consequence of the effect of zero-point vibrations on the rates of transition in the localized process of activation. An attempt is made to explain the anomalies by introducing a "strain-enhancement" effect, i.e., f(T), semiempirically in the logrithmic creep equation [Formula: see text] where Teff = T0 + AT2 (T0 and A are constants), which allows for quantum effects below a certain temperature.

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