Nonlinear Elastic Deformation of MAX Phases

2010 ◽  
Vol 434-435 ◽  
pp. 149-153 ◽  
Author(s):  
Ai Guo Zhou ◽  
M.W. Barsoum
Keyword(s):  
Elastic Deformation ◽  
Mathematic Model ◽  
Layered Crystal ◽  
Deformation History ◽  
Max Phases ◽  
Complex Deformation ◽  
Mechanical Hysteresis ◽  
Layered Crystal Structure ◽  
Nonlinear Elastic ◽  
Ternary Carbides

MAX phases, include Ti3SiC2, Ti2AlC etc, are machinable ternary carbides or nitrides with excellent properties. These materials, however, have obvious nonlinear elastic deformation due to nano- layered crystal structure. The stress-strain curves of cyclically load-unload test have obvious hysteretic loops. Because of this mechanical hysteresis, the strain of MAX phases at one time is not determined only by the stress applied to the sample at this time. Here the influence of grain size, chemical composition and porosity on the nonlinear elastic strain was introduced. Because of two properties of this hysteresis: wiping out and congruency, the classic hysteretic mathematic model (Preisach-Mayergoyz model, P-M model) can be applied to calculate the strain of MAX phases after any complex deformation history.

scholarly journals The layered crystal structure of bis(theophyllinium) hexachloridostannate (IV), C14H18N8O8SnCl6

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guido J. Reiss ◽  
Maik Wyshusek
Keyword(s):  
Crystal Structure ◽  
Layered Crystal ◽  
Layered Crystal Structure

Abstract C14H18N8O8SnCl6, monoclinic, P21/n (no. 14), a = 8.1810(2) Å, b = 12.6195(3) Å, c = 11.3811(2) Å, β = 90.258(2)°, Z = 2, V = 1174.97(5) Å3, R gt(F) = 0.0266, wR ref = 0.0620, T = 290 K.

Crystal structure of oxybutynin hydrochloride hemihydrate, C22H32NO3Cl(H2O)0.5

2019 ◽  
Vol 34 (1) ◽  
pp. 50-58
Author(s):  
James A. Kaduk ◽  
Nicholas C. Boaz ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Density Functional ◽  
Hydroxyl Group ◽  
Layered Crystal ◽  
Powder Diffraction File ◽  
X Ray ◽  
Layered Crystal Structure ◽  
Oxybutynin Hydrochloride

The crystal structure of oxybutynin hydrochloride hemihydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Oxybutynin hydrochloride hemihydrate crystallizes in space group I2/a (#15) with a = 14.57266(8), b = 8.18550(6), c = 37.16842(26) Å, β = 91.8708(4)°, V = 4421.25(7) Å3, and Z = 8. The compound exhibits X-ray-induced photoreduction of the triple bond. Prominent in the layered crystal structure is the N–H⋅⋅⋅Cl hydrogen bond between the cation and anion, as well as O–H⋅⋅⋅Cl hydrogen bonds from the water molecule and hydroxyl group of the oxybutynin cation. C–H⋅⋅⋅Cl hydrogen bonds also contribute to the crystal energy, and help determine the conformation of the cation. The powder pattern is included in the Powder Diffraction File™ as entry 00-068-1305.

scholarly journals Study of anisotropic thermal conductivity in textured thermoelectric alloys by Raman spectroscopy

RSC Advances ◽  
2021 ◽  
Vol 11 (39) ◽  
pp. 24456-24465
Author(s):  
Rapaka S. C. Bose ◽  
K. Ramesh
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Raman Spectroscopy ◽  
Transport Properties ◽  
Thermal Transport ◽  
Layered Crystal ◽  
Layered Crystal Structure ◽  
Thermal Transport Properties ◽  
Anisotropic Thermal Conductivity ◽  
P Type

Polycrystalline p-type Sb1.5Bi0.5Te3 (SBT) and n-type Bi2Te2.7Se0.3 (BTS) compounds possessing layered crystal structure show anisotropic electronic and thermal transport properties.

scholarly journals The Rosebel gold district (Trans-Amazonian belt, Suriname), a new structural framework

2021 ◽  
Author(s):  
Denis Gapais ◽  
Gilian Alimoenadi ◽  
Nicole Balraadjsing ◽  
Benoît Poupeau
Keyword(s):  
Fault Slip ◽  
Finite Strains ◽  
Continental Lithosphere ◽  
Deformation History ◽  
Complex Deformation ◽  
Crustal Shortening ◽  
Strain Pattern ◽  
Structural Framework

The Rosebel gold district belongs to the Paleoproterozoic Trans-Amazonian belt associated with sub-meridian crustal shortening. Here, we present new structural observations (cleavage, stretching lineations, veins, fault slip data, aeromagnetic maps). Regional cleavages are steeply dipping and bear steeply plunging stretching lineations. Finite strains are of flattening type. Fault slip data reveal a complex deformation history. The overall strain pattern of the reflects vertical motions, a feature consistent with pop-down tectonics involving vertical stretch and burial of supracrustal deposits during horizontal shortening of a hot and weak continental lithosphere.

Synthesis and elastic and mechanical properties of Cr2GeC

2008 ◽  
Vol 23 (8) ◽  
pp. 2157-2165 ◽  
Author(s):  
Shahram Amini ◽  
Aiguo Zhou ◽  
Surojit Gupta ◽  
Andrew DeVillier ◽  
Peter Finkel ◽  
...  
Keyword(s):  
Mechanical Energy ◽  
Kink Band ◽  
Max Phase ◽  
Elastic Solids ◽  
Max Phases ◽  
Kink Bands ◽  
Young’S Moduli ◽  
Microscale Model ◽  
Energy Dissipated ◽  
Nonlinear Elastic

Herein we report on the synthesis and characterization of Cr2GeC, a member of the so-called Mn+1AXn (MAX) phase family of layered machinable carbides and nitrides. Polycrystalline samples were synthesized by hot pressing pure Cr, Ge, and C powders at 1350 °C at ∼45 MPa for 6 h. No peaks other than those associated with Cr2GeC and Cr2O3, in the form of eskolaite, were observed in the x-ray diffraction spectra. The samples were readily machinable and fully dense. The steady-state Vickers hardness was 2.5 ± 0.1 GPa. The Young’s moduli measured in compression and by ultrasound were 200 ± 10 and 245 ± 3 GPa, respectively; the shear modulus and Poisson’s ratio deduced from the ultrasound results were 80 GPa and 0.29, respectively. The ultimate compressive strength for a ∼20 μm grain size sample was 770 ± 30 MPa. Samples compressively loaded from 300 to ∼570 MPa exhibited nonlinear, fully reversible, reproducible, closed hysteretic loops that dissipated ∼20% of the mechanical energy, a characteristic of the MAX phases, in particular, and kinking nonlinear elastic solids, in general. The energy dissipated is presumably due to the formation and annihilation of incipient kink bands. The critical resolved shear stress of the basal plane dislocations—estimated from our microscale model—is ∼22 MPa. The incipient kink band and reversible dislocation densities, at the maximum stress of 568 MPa, are estimated to be 1.2 × 10−2 μm−3 and 1.0 × 1010 cm−2, respectively.

Synthesis, crystal and electronic structure of BaLi2Cd2Ge2

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sviatoslav Baranets ◽  
Alexander Ovchinnikov ◽  
Svilen Bobev
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Fermi Level ◽  
Structure Type ◽  
Layered Crystal ◽  
Electronic Density ◽  
Electronic Band ◽  
Cell Parameters ◽  
Layered Crystal Structure ◽  
Electronic Band Gap

Abstract A new quaternary germanide has been synthesized and structurally characterized. BaLi2Cd2Ge2 adopts the rhombohedral CaCu4P2 structure type (Pearson code hR7; space group R 3 ‾ m $R‾{3}m$ , Z = 3) with unit cell parameters a = 4.5929(6) and c = 26.119(5) Å. Structure refinements from single-crystal X-ray diffraction data demonstrate that the layered crystal structure can be regarded as an ordered quaternary variant of the ternary archetype; structural parallels to layered pnictides and binary germanides can also be drawn. The layered crystal structure is characterized by the absence of direct Ge–Ge and Cd–Cd homoatomic bonds, which suggests that BaLi2Cd2Ge2 should be classified as a Zintl phase, according to the formulation (Ba2+)(Li+)2(Cd2+)2(Ge4−)2. Electronic structure calculations show that the Fermi level crosses a distinct peak in the DOS, although the presence of an electronic band gap or a dip in the electronic density of states at the Fermi level is expected based on the electron partitioning.

A two-dimensional ion-pump of a vanadium pentoxide nanofluidic membrane

2019 ◽  
Vol 7 (17) ◽  
pp. 10552-10560 ◽  
Author(s):  
Raj Kumar Gogoi ◽  
Arindom Bikash Neog ◽  
Tukhar Jyoti Konch ◽  
Neelam Sarmah ◽  
Kalyan Raidongia
Keyword(s):  
Crystal Structure ◽  
Vanadium Pentoxide ◽  
Concentration Gradient ◽  
Layered Crystal ◽  
Ion Pump ◽  
Two Dimensional ◽  
Reactive Surface ◽  
Layered Crystal Structure

The reactive surface and layered crystal structure of vanadium pentoxide (V2O5) are exploited here to prepare a two-dimensional (2D) ion pump that transports ions against their concentration gradient.

scholarly journals Structural Design for a 10-GWh SMES Vacuum Vessel

1978 ◽  
Vol 100 (3) ◽  
pp. 263-270
Author(s):  
J. G. Bennett ◽  
C. A. Anderson
Keyword(s):  
Cylindrical Shell ◽  
Approximate Solution ◽  
Elastic Deformation ◽  
Material Properties ◽  
Structural Design ◽  
Shell Thickness ◽  
Construction Cost ◽  
Vacuum Vessel ◽  
Nonlinear Elastic

An approximate solution to the problem of the nonlinear elastic deformation of a periodically point-supported cylindrical shell is obtained. This solution is used to investigate the structural design of the vacuum vesssel for the large underground SMES concept. Vacuum vessel designs are evaluated by varying such parameters as shell thickness, support, spacing, material properties and physical configuration to keep the amount of material used and construction cost to a minimum.

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