Hardness and elastic modulus from nanoindentations in nominally pure and doped MgO single crystals

Mechanical properties of (001) Mo and (001) Mo – 1.5 at.% Ir single crystals have been studied by nanoindentation. It has been found that the iridium addition to molybdenum leads to an increase in both hardness and elastic modulus. An abrupt elasto-plastic transition (pop-in) at a depth of about 20 - 40 nm caused by dislocation nucleation in previously dislocation-free volume has been observed in the initial portion of the loading curve. It has shown that the Ir addition essentially affects the dislocation nucleation. Mean shear stress required for the dislocation nucleation increased from 10.8 GPa (G/12) for a Mo single crystal to 18.2 GPa (G/8) for the Mo – 1.5 at% Ir solid solution. Thus, the Ir solution in a Mo single crystal affects not only the resistance to the motion of dislocations (hardness) but the nucleation of them as well. The latter is likely to occur as a result of an increase in the structure perfection of the Mo – 1.5 at% Ir solid solution as compared to the pure Mo single crystal.

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Effects of Crystal Orientation and Grain Boundary Inclination on Stress Distribution in Bicrystal Interface of Austenite Stainless Steel 316L

Advances in Materials Science and Engineering ◽

10.1155/2019/2468487 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Fu-qiang Yang ◽

He Xue ◽

Ling-yan Zhao ◽

Xiu-Rong Fang ◽

Hai-bing Zhang

Keyword(s):

Grain Size ◽

Stainless Steel ◽

Elastic Modulus ◽

Grain Boundary ◽

Single Crystals ◽

Crystal Orientation ◽

Stress And Strain ◽

Face Centered Cubic ◽

Stainless Steel 316L ◽

Load Direction

Nuclear structural material austenitic stainless steel 316L is a polycrystalline composed of single crystals with a face-centered cubic (FCC) structure, and the intergranular stress corrosion cracking (IGSCC) is closely related to the crystal orientation. A constitutive model is presented to assess the elastic response of anisotropic behavior of single crystals in 316L in this study. With a bicrystal model built by the finite element method, the effects of crystal orientation and grain boundary (GB) inclination on the stress state nearby a symmetric tilt GB were discussed under the constant-displacement condition. The results indicate that when tensile axes are perpendicular to the GB, the stress and strain are equal at the GB and inside the grain, and the crystal misorientation has little effects on the stress and strain distribution. If the GB is not perpendicular to the load direction, the GB inclination angle will change the equivalent elastic modulus along the load direction and result in a larger stress in the grain with larger equivalent elastic modulus, but the stress tends to be equal inside the two grains. The grain size effects verification shows that the conclusions are independent of grain size.

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Nanoindentation and ellipsometry of Li2ZnTi3O8& Zn2TiO4single crystals

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314088834 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1116-C1116

Author(s):

Lukas Perfler ◽

Volker Kahlenberg ◽

Christoph Wikete ◽

Reinhard Kaindl

Keyword(s):

Elastic Modulus ◽

Single Crystals ◽

Maximum Load ◽

Industrial Applications ◽

X Ray Diffraction ◽

Spinel Type ◽

Structural Investigations ◽

Atomic Force ◽

Diamond Indenter ◽

Dielectric Devices

Spinel-type Li2ZnTi3O8and Zn2TiO4are useful for various industrial applications due to their interesting chemical and physical properties, for example, as promising anode materials in Li-ion batteries or as components in dielectric devices [1]. Since Li2ZnTi3O8and Zn2TiO4are expected to have high refractive indices (n calc. = 2,33 and 2,26) we tried to characterize these materials in more detail including single-crystal X-ray diffraction, nanoindentation, spectroscopic ellipsometry and electron microprobe analysis. Single crystals of Li2ZnTi3O8and Zn2TiO4were grown directly from melt at 1723 K and 1873 K, respectively. Fragments of sintered polycrystalline Li2ZnTi3O8and Zn2TiO4precursors were placed on an iridium sheet and fired in a muffle furnace from 1273 to 1723/1873 K with a heating ramp of 15 K/min. After a dwell time of 3 min the melt was cooled down to 1473 K with a ramp of 10 K/min and subsequently quenched in water. Structural investigations of the Li2ZnTi3O8and Zn2TiO4single crystals resulted in the following basic crystallographic data: cubic, P4332, a = 8.3697(2) Å, V = 586.31(3) Å3, Z = 4 and Fd-3m, a = 8.46230(17) Å, V = 605.99(2) Å3, Z = 8, respectively. Nanoindentation experiments were performed with a Berkovich diamond indenter tip to determine the hardness and elastic modulus of Zn2TiO4and Li2ZnTi3O8. For sample preparation the single crystals were embedded in resin and polished to a mirror-like surface finish. More than 150 indents with a distance of 10 µm were made with a maximum load of 20 mN. Analysis of the load-displacement curves for Zn2TiO4revealed a hardness of 10.5110.39 GPa and a reduced elastic modulus of 180.9013.92 GPa. Atomic force micrographs displayed indents with a max. depth of 28815 nm. Li2ZnTi3O8exhibited a hardness of 6.8610.45 GPa and a reduced elastic modulus of 148.8816 GPa. Zn2TiO4showed a dispersion of 0.09 due to the variation of the refractive index from 2.24 (430,8 nm, Fraunhofer G line) and 2.15 (686,7 nm, B line).

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Mechanical behavior assessment of sucrose using nanoindentation

Journal of Materials Research ◽

10.1557/jmr.2007.0249 ◽

2007 ◽

Vol 22 (7) ◽

pp. 2037-2045 ◽

Cited By ~ 53

Author(s):

K.J. Ramos ◽

D.F. Bahr

Keyword(s):

Experimental Study ◽

Plastic Deformation ◽

Shear Stress ◽

Elastic Modulus ◽

Slip System ◽

Single Crystals ◽

Maximum Shear Stress ◽

Model Material ◽

Instrumented Indentation ◽

Plastic Properties

An experimental study of the elastic and plastic properties of sucrose single crystals, which can be considered to be a model material for both pharmaceutical excipients and explosives, has been carried out using nanoindentation. Instrumented indentation was used to characterize the properties of both habit and cleavage planes on the (100) and (001) orientations; the elastic modulus on the (100) is 38 GPa, while the modulus on the (001) is 33 GPa. The hardness of sucrose is approximately 1.5 GPa. Nanoindentation enables assessment of the onset of plastic deformation on cleaved surfaces, and a maximum shear stress of 1 GPa can be supported prior to plastic deformation. The deformation in this material is crystallographically dependent, with pileup around residual indentation impressions showing evidence of preferential slip system activity.

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Dislocation Processes and Deformation Behavior in -Oriented FeX-Ni60–X-Al40 Single Crystals

MRS Proceedings ◽

10.1557/proc-646-n6.1.1 ◽

2000 ◽

Vol 646 ◽

Author(s):

P. S. Brenner ◽

R. Srinivasan ◽

R. D. Noebe ◽

T. Lograsso ◽

M. J. Mills

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Yield Strength ◽

Strain Hardening ◽

Single Crystals ◽

Deformation Behavior ◽

Room Temperature ◽

Elevated Temperatures ◽

Pseudobinary System ◽

Dislocation Dissociation

ABSTRACTThe mechanical properties and dislocation microstructure of single crystals with a range of compositions within the Fex-Ni60–x-Al40 pseudobinary system have been investigated, with the purpose of bridging the behavior from FeAl to NiAl. Experiments are focused on the compression testing of <001> oriented single crystals with compositions where x = 10, 20, 30, 40, and 50 (in atomic percent). Observations of a<111> dislocation morphologies at room temperature and both a<111> and non-a<111> dislocation activity at elevated temperatures are reported and discussed. Measurements of the yield strength, elastic modulus and strain hardening rates are reported, and the variation of strength with composition is correlated with dislocation dissociation and overall dislocation morphology.

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Auxeticity Properties of Hexagonal Syngony Crystals

Фізика і хімія твердого тіла ◽

10.15330/pcss.16.1.34-43 ◽

2015 ◽

Vol 16 (1) ◽

pp. 34-43 ◽

Cited By ~ 3

Author(s):

M. D. Raransky ◽

V. N. Balazyuk ◽

M .M. Gunko

Keyword(s):

Elastic Modulus ◽

Single Crystals ◽

Hexagonal System ◽

Experimental Values ◽

First Time ◽

Hexagonal Crystals ◽

Hexagonal Syngony

Pointing auxeticity surfaces of Be, Zn, MoS2, MnAs, TiB2 and BeCu (2,4 atm. % Cu) single crystals of hexagonal system were plotted for the first time using the experimental values of the elastic modulus , which given in the tables Landolt-Bernstein. The criteria of appearance of axial and noaksial auxeticity were established. The influence of alloying and temperature on effects of Be abnormal deformation was detected. The mechanisms of auxeticity properties formation in hexagonal crystals were established.

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Hardness and elastic modulus from nanoindentations in nominally pure and doped MgO single crystals

Philosophical Magazine A ◽

10.1080/01418610208240022 ◽

2002 ◽

Vol 82 (6) ◽

pp. 1159-1171 ◽

Cited By ~ 15

Author(s):

D. Cáceres ◽

I. Vergara ◽

R. González ◽

Y. Chen

Keyword(s):

Elastic Modulus ◽

Single Crystals

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Nanoindentation measurement of hardness and modulus anisotropy in Ni3Al single crystals

Journal of Materials Research ◽

10.1557/jmr.2002.0339 ◽

2002 ◽

Vol 17 (9) ◽

pp. 2314-2320 ◽

Cited By ~ 27

Author(s):

W. Wang ◽

K. Lu

Keyword(s):

Elastic Modulus ◽

Single Crystals ◽

Indentation Load ◽

Indentation Hardness ◽

Gradient Plasticity ◽

Indentation Size ◽

Hardness Anisotropy ◽

Nanoindentation Measurement ◽

Small Anisotropy ◽

Strain Gradient Plasticity Theory

Hardness and elastic modulus of (111), (110), and (001) oriented Ni3Al single crystals were determined by nanoindenter measurements. Obvious elastic modulus anisotropy and hardness anisotropy were observed. The modulus for (001) was about 17% smaller than that for (111), (110). The hardness was found to be strongly dependent on the indentation size and exhibited a small anisotropy at low indentation loads. When the indentation load was increased further, the hardness anisotropy became apparent. The hardness for (111) was observed to be higher compared to (001). The indentation hardness size effect was examined by using strain gradient plasticity theory.

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Mechanical Properties and Deformation of LiTaO3 Single Crystals Characterised by Nanoindentation and Nanoscratch

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.565.564 ◽

2012 ◽

Vol 565 ◽

pp. 564-569 ◽

Cited By ~ 2

Author(s):

An Shun He ◽

Han Huang ◽

Li Bo Zhou

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Single Crystals ◽

Material Removal ◽

Normal Load ◽

Indentation Load ◽

Machining Process ◽

Kink Bands

This paper reports our recent results on the nanoindentation and nanoscratch of LiTaO3 single crystals. The elastic modulus and hardness of LiTaO3 obtained from nanoindentation were 251±3 GPa and 12.6±0.6 GPa, respectively. During indenting, pop-in events occurred when indentation load was in the range from 305 to 640 μN. Incipient kink bands (IKBs) were believed to be responsible for the pop-ins. Nanoscratching showed that there existed a threshold normal load of 2.5 mN, above which cracks were generated and the material removal was in the brittle regime. The knowledge gained is valuable to the design of an effective machining process for LiTaO3 crystals.

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