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A M Bhola - One of the best experts on this subject based on the ideXlab platform.
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Kink Bands in thrust regime: Examples from Srinagar–Garhwal area, Uttarakhand, India
Journal of Earth System Science, 2011Co-Authors: Shashank Shekhar, A M Bhola, P S SaklaniAbstract:This paper deciphers the late stress systems involved in the development of Kink Bands in the perspective of thrust regime. In Kink Bands, the correlation coefficient for α–β plots is positive near thrusts and negative away from thrusts. The plots show nearly linear relationship near thrusts and non-linear relationship away from thrusts. The rotation was prominent mechanism of Kink band formation near thrusts and rotation coupled with shearing, along the Kink planes away from thrusts. Along thrusts σ1 is horizontal E–W trend and it rotates to horizontal N–S trend away from the thrust. The proposed model establishes that (1) the shearing along Kink planes led to angular relationship, β < α and (2) the Kink planes of conjugate Kinks could be used for paleostress analysis even in those cases where shearing along these planes has occurred.
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Kink Bands in thrust regime examples from srinagar garhwal area uttarakhand india
Journal of Earth System Science, 2011Co-Authors: Shashank Shekhar, A M Bhola, P S SaklaniAbstract:This paper deciphers the late stress systems involved in the development of Kink Bands in the perspective of thrust regime. In Kink Bands, the correlation coefficient for α–β plots is positive near thrusts and negative away from thrusts. The plots show nearly linear relationship near thrusts and non-linear relationship away from thrusts. The rotation was prominent mechanism of Kink band formation near thrusts and rotation coupled with shearing, along the Kink planes away from thrusts. Along thrusts σ1 is horizontal E–W trend and it rotates to horizontal N–S trend away from the thrust. The proposed model establishes that (1) the shearing along Kink planes led to angular relationship, β < α and (2) the Kink planes of conjugate Kinks could be used for paleostress analysis even in those cases where shearing along these planes has occurred.
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Kink Bands in the chamba region western himalaya india
Journal of Asian Earth Sciences, 2005Co-Authors: B K Sharma, A M BholaAbstract:Abstract The Chamba region of the western Himalaya is affected by three phases of deformation (DF1, DF2, and DF3). The DF1 phase was the most intense and regionally extensive as expressed by the development of the Chamba-Bhramaur syncline. The Kink Bands developed on the limbs of the syncline during the third (DF3) phase of deformation on S1 fabric. The Kink Bands are of contractional type and well developed in the slate-phyllite sequence of the Salooni and Pukhri Formations. The palaeostress analysis from conjugate Kink Bands indicates that the maximum compressive stress (σ1) was oriented N50°E–S50°W in present coordinates, which nearly coincides with the maximum compressive direction inferred from DF1 (First phase) and DF2 (second phase) deformation. The geometry, angular relationship between the Kink band boundary and the external cleavage (α) and the internal angle of the Kink band (β) and strain in Kink Bands reveal that rotation and dilation was the dominant mechanism. The morphology, kinematics and dynamics of the Kink Bands suggest that they formed towards the end of the last phase of deformation during emplacement of the Chamba nappe without metamorphism.
Michel W Barsoum - One of the best experts on this subject based on the ideXlab platform.
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Single crystal pillar microcompression tests of the MAX phases Ti2InC and Ti4AlN3
Scripta Materialia, 2013Co-Authors: Christoph Brüsewitz, Hans Hofsäss, Inga Knorr, Michel W Barsoum, Cynthia A. VolkertAbstract:The deformation behavior of micron-sized, single crystal specimens of the MAX phases Ti 2 InC and Ti 4 AlN 3 has been investigated under uniaxial compression. Deformation took place by slip on single planes or sets of parallel planes. For highly inclined slip planes, where slip was hindered by the substrate or punch, deformation was accompanied by micro-cracking, layer bending, and the formation of Kink Bands. This study confirms the importance of obstacles in the deformation behavior and strength of MAX phases.
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Microscale modeling of Kinking nonlinear elastic solids
Physical Review B - Condensed Matter and Materials Physics, 2005Co-Authors: Michel W Barsoum, Tan Zhen, A Zhou, S. Basu, Surya R KalidindiAbstract:Recently we identified and classified a class of solids as Kinking nonlinear elastic (KNE) because they deform by the formation of Kink Bands. KNE solids represent a large family that include, among others, layered ternary carbides and nitrides, layered oxides and semiconductors, zinc, cadmium, graphite, ice, and the layered silicates, such as mica, present in nonlinear mesoscopic elastic solids. Herein we present a microscale model that accounts for the mechanical response of KNE solids to compressive stresses and apply it to two very different solids: Ti3 SiC2 and graphite. Building on the Frank and Stroh model put forth in the 1950's for the formation of Kink Bands, we developed a comprehensive theory that accounts for the contributions of incipient Kink Bands (IKBs) and dislocations pile-ups produced by normal glide processes to the nonlinear strains and stored strain energies. The theory provides estimates for the densities of IKBs, the dislocation densities, both from the IKBs and dislocation pileups, as well as the energy dissipated by the motion of the dislocations. © 2005 The American Physical Society.
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Kink Bands nonlinear elasticity and nanoindentations in graphite
Carbon, 2004Co-Authors: Michel W Barsoum, Tan Zhen, Anand Murugaiah, Surya R Kalidindi, Yury GogotsiAbstract:Abstract Herein we report on the response of graphite single crystals––loaded parallel to their c -axis––to a 13.5 μm radius spherical diamond nanoindenter. Up to loads of 5 mN, corresponding to stresses of ≈0.5 GPa, fully reversible hysteresis loops are observed. At stresses >0.5 GPa, the first loops are slightly open; subsequent loops, in the same location, are fully reversible and harder than the first. Simple compression experiments on polycrystalline cylinders yielded qualitatively similar results. Our results, together with much of the literature on the mechanical properties of graphite, can be explained by invoking the formation of incipient Kink Bands, IKB's, that give way to mobile dislocation walls that, in turn, coalesce into Kink boundaries with increasing stress. The IKB's are fully reversible; the dislocation walls result in plastic deformation, and the Kink boundaries explain the hardening. Since the dislocations are confined to the basal planes, they cannot entangle and can thus move reversibly over relatively large distances resulting in the dissipation of substantial amounts (up to 100 MJ/m 3 ) of energy during each cycle. At stresses >1.5 GPa, massive pop-ins––of the order of 60 μm––are observed. Examination of the craters formed provided direct evidence for Kink Bands and the formation of a multitude of subgrains under the indenter. Based on this work, it is clear that graphite is a member of a larger class of solids––Kinking nonlinear elastic solids––that includes the M n +1 AX n phases, layered silicates, nonlinear mesoscopic elastic solids, among others.
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Fully reversible, dislocation-based compressive deformation of Ti_3SiC_2 to 1 GPa
Nature Materials, 2003Co-Authors: Michel W Barsoum, Miladin Radovic, Tan Zhen, Surya R Kalidindi, Anand MurugaiahAbstract:Dislocation-based deformation in crystalline solids is almost always plastic. Here we show that polycrystalline samples of Ti_3SiC_2 loaded cyclically at room temperature, in compression, to stresses up to 1 GPa, fully recover on the removal of the load, while dissipating about 25% (0.7 MJ m^−3) of the mechanical energy. The stress–strain curves outline fully reversible, rate-independent, closed hysteresis loops that are strongly influenced by grain size, with the energy dissipated being significantly larger in the coarse-grained material. At temperatures greater than 1,000 °C, the loops are open, the response is strain-rate dependent, and cyclic hardening is observed. This hitherto unreported phenomenon is attributed to the reversible formation and annihilation of incipient Kink Bands at room-temperature deformation. At higher temperatures, the incipient Kink Bands dissociate and coalesce to form regular irreversible Kink Bands. The loss factor for Ti_3SiC_2 is higher than most woods, and comparable to polypropylene and nylon. The technological implications of having a stiff, lightweight machinable ceramic that can dissipate up to 25% of the mechanical energy per cycle are discussed.
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Dislocations, Kink Bands, and room-temperature plasticity of Ti3SiC2
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 1999Co-Authors: Michel W Barsoum, L Färber, Tamer El-raghyAbstract:Transmission electron microscopy (TEM) of aligned, macrograined samples of Ti 3 SiC 2 , deformed at room temperature, shows that the deformed microstructure is characterized by a high density of perfect basal-plane dislocations with a Burgers vector of 1/3〈112̄0〉. The dislocations are overwhelmingly arranged either in arrays, wherein the dislocations exist on identical slip planes, or in dislocations walls, wherein the same dislocations form a low-angle grain boundary normal to the basal planes. The arrays propagate across entire grains and are responsible for deformation by shear. The walls form as a result of the formation of Kink Bands. A dislocation-based model, that builds on earlier ideas proposed for Kink-band formation in hexagonal metallic single crystals, is presented, which explains most of the microstructural features. The basic elements of the model are shear deformation by dislocation arrays, cavitation, creation of dislocation walls and Kink boundaries, buckling, and delamination. The delaminations are not random, but successively bisect the delaminating sections. The delaminations and associated damage are contained by the Kink boundaries. This containment of damage is believed to play a major role in endowing Ti 3 SiC 2 and, by extension, related ternary carbides and nitrides with their damage-tolerant properties.
Surya R Kalidindi - One of the best experts on this subject based on the ideXlab platform.
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incipient and regular Kink Bands in fully dense and 10 vol porous ti2alc
Acta Materialia, 2006Co-Authors: Ai Guo Zhou, Surya R Kalidindi, M W Barsoum, Sandip Basu, T ElraghyAbstract:Abstract The ternary carbide Ti2AlC is a member of a large class of solids recently classified as Kinking nonlinear elastic (KNE) solids because they deform primarily by the formation of Kink Bands. We report on the response of fully dense and 10 vol.% porous polycrystalline Ti2AlC samples to uniaxial compression and indentation by a hemispherical nanoindenter. The salient features of the Kinking-induced behavior can be described by four interrelated loading parameters (stress σ, nonlinear strain eNL, stored nonlinear energy per unit volume UNL, and dissipated energy per unit volume Wd) all of which can be obtained from stress–strain curves. The experimental data described are in excellent agreement with our recently proposed model for KNE solids. In the model, Wd scales with σ2 and UNL with e NL 1.5 , both predictions observed over a very large stress range. Analysis of the results further indicates that the dislocation density, at the maximum stress of 350 MPa, is ∼1013 m−2. From the model, the critical resolved shear stress on the basal planes can also be estimated. In the present case, it is ∼22 MPa.
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Microscale modeling of Kinking nonlinear elastic solids
Physical Review B - Condensed Matter and Materials Physics, 2005Co-Authors: Michel W Barsoum, Tan Zhen, A Zhou, S. Basu, Surya R KalidindiAbstract:Recently we identified and classified a class of solids as Kinking nonlinear elastic (KNE) because they deform by the formation of Kink Bands. KNE solids represent a large family that include, among others, layered ternary carbides and nitrides, layered oxides and semiconductors, zinc, cadmium, graphite, ice, and the layered silicates, such as mica, present in nonlinear mesoscopic elastic solids. Herein we present a microscale model that accounts for the mechanical response of KNE solids to compressive stresses and apply it to two very different solids: Ti3 SiC2 and graphite. Building on the Frank and Stroh model put forth in the 1950's for the formation of Kink Bands, we developed a comprehensive theory that accounts for the contributions of incipient Kink Bands (IKBs) and dislocations pile-ups produced by normal glide processes to the nonlinear strains and stored strain energies. The theory provides estimates for the densities of IKBs, the dislocation densities, both from the IKBs and dislocation pileups, as well as the energy dissipated by the motion of the dislocations. © 2005 The American Physical Society.
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spherical nanoindentations and Kink Bands in ti3sic2
Journal of Materials Research, 2004Co-Authors: Anand Murugaiah, Surya R Kalidindi, M W Barsoum, T ZhenAbstract:We report for the first time on load versus depth-of-indentation response of Ti 3 SiC 2 surfaces loaded with a 13.5 μm spherical tipped diamond indenter up to loads of 500 mN. Using orientation imaging microscopy, two groups of crystals were identified; one in which the basal planes were parallel to, and the other normal to, the surface. When the load-penetration depth curves were converted to stress-strain curves the following was apparent: when the surfaces were loaded normal to the c axis, the response at the lowest loads was linear elastic—well described by a modulus of 320 GPa—followed by a clear yield point at approximately 4.5 GPa. And while the first cycle was slightly open, the next 4 on the same location were significantly harder, almost indistinguishable, and fully reversible. At the highest loads (500 mN) pop-ins due to delaminations between basal planes were observed. When pop-ins were not observed the indentations, for the most part, left no trace. When the load was applied parallel to the c axis, the initial response was again linear elastic (modulus of 320 GPa) followed by a yield point of approximately 4 GPa. Here again significant hardening was observed between the first and subsequent cycles. Each cycle resulted in some strain, but no concomitant increase in yield points. This orientation was even more damage tolerant than the orthogonal direction. This response was attributed to the formation of incipient Kink Bands that lead to the formation of regular Kink Bands. Remarkably, these dislocation-based mechanisms allow repeated loading of Ti 3 SiC 2 without damage, while dissipating significant amounts of energy per unit volume, W d , during each cycle. The values of W d measured herein were in excellent agreement with corresponding measurements in simple compression tests reported earlier, confirming that the same mechanisms continue to operate even at the high (≈9 GPa) stress levels typical of the indentation experiments.
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Kink Bands nonlinear elasticity and nanoindentations in graphite
Carbon, 2004Co-Authors: Michel W Barsoum, Tan Zhen, Anand Murugaiah, Surya R Kalidindi, Yury GogotsiAbstract:Abstract Herein we report on the response of graphite single crystals––loaded parallel to their c -axis––to a 13.5 μm radius spherical diamond nanoindenter. Up to loads of 5 mN, corresponding to stresses of ≈0.5 GPa, fully reversible hysteresis loops are observed. At stresses >0.5 GPa, the first loops are slightly open; subsequent loops, in the same location, are fully reversible and harder than the first. Simple compression experiments on polycrystalline cylinders yielded qualitatively similar results. Our results, together with much of the literature on the mechanical properties of graphite, can be explained by invoking the formation of incipient Kink Bands, IKB's, that give way to mobile dislocation walls that, in turn, coalesce into Kink boundaries with increasing stress. The IKB's are fully reversible; the dislocation walls result in plastic deformation, and the Kink boundaries explain the hardening. Since the dislocations are confined to the basal planes, they cannot entangle and can thus move reversibly over relatively large distances resulting in the dissipation of substantial amounts (up to 100 MJ/m 3 ) of energy during each cycle. At stresses >1.5 GPa, massive pop-ins––of the order of 60 μm––are observed. Examination of the craters formed provided direct evidence for Kink Bands and the formation of a multitude of subgrains under the indenter. Based on this work, it is clear that graphite is a member of a larger class of solids––Kinking nonlinear elastic solids––that includes the M n +1 AX n phases, layered silicates, nonlinear mesoscopic elastic solids, among others.
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Fully reversible, dislocation-based compressive deformation of Ti_3SiC_2 to 1 GPa
Nature Materials, 2003Co-Authors: Michel W Barsoum, Miladin Radovic, Tan Zhen, Surya R Kalidindi, Anand MurugaiahAbstract:Dislocation-based deformation in crystalline solids is almost always plastic. Here we show that polycrystalline samples of Ti_3SiC_2 loaded cyclically at room temperature, in compression, to stresses up to 1 GPa, fully recover on the removal of the load, while dissipating about 25% (0.7 MJ m^−3) of the mechanical energy. The stress–strain curves outline fully reversible, rate-independent, closed hysteresis loops that are strongly influenced by grain size, with the energy dissipated being significantly larger in the coarse-grained material. At temperatures greater than 1,000 °C, the loops are open, the response is strain-rate dependent, and cyclic hardening is observed. This hitherto unreported phenomenon is attributed to the reversible formation and annihilation of incipient Kink Bands at room-temperature deformation. At higher temperatures, the incipient Kink Bands dissociate and coalesce to form regular irreversible Kink Bands. The loss factor for Ti_3SiC_2 is higher than most woods, and comparable to polypropylene and nylon. The technological implications of having a stiff, lightweight machinable ceramic that can dissipate up to 25% of the mechanical energy per cycle are discussed.
P S Saklani - One of the best experts on this subject based on the ideXlab platform.
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Kink Bands in thrust regime examples from srinagar garhwal area uttarakhand india
Journal of Earth System Science, 2011Co-Authors: Shashank Shekhar, A M Bhola, P S SaklaniAbstract:This paper deciphers the late stress systems involved in the development of Kink Bands in the perspective of thrust regime. In Kink Bands, the correlation coefficient for α–β plots is positive near thrusts and negative away from thrusts. The plots show nearly linear relationship near thrusts and non-linear relationship away from thrusts. The rotation was prominent mechanism of Kink band formation near thrusts and rotation coupled with shearing, along the Kink planes away from thrusts. Along thrusts σ1 is horizontal E–W trend and it rotates to horizontal N–S trend away from the thrust. The proposed model establishes that (1) the shearing along Kink planes led to angular relationship, β < α and (2) the Kink planes of conjugate Kinks could be used for paleostress analysis even in those cases where shearing along these planes has occurred.
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Kink Bands in thrust regime: Examples from Srinagar–Garhwal area, Uttarakhand, India
Journal of Earth System Science, 2011Co-Authors: Shashank Shekhar, A M Bhola, P S SaklaniAbstract:This paper deciphers the late stress systems involved in the development of Kink Bands in the perspective of thrust regime. In Kink Bands, the correlation coefficient for α–β plots is positive near thrusts and negative away from thrusts. The plots show nearly linear relationship near thrusts and non-linear relationship away from thrusts. The rotation was prominent mechanism of Kink band formation near thrusts and rotation coupled with shearing, along the Kink planes away from thrusts. Along thrusts σ1 is horizontal E–W trend and it rotates to horizontal N–S trend away from the thrust. The proposed model establishes that (1) the shearing along Kink planes led to angular relationship, β < α and (2) the Kink planes of conjugate Kinks could be used for paleostress analysis even in those cases where shearing along these planes has occurred.
Karen I Winey - One of the best experts on this subject based on the ideXlab platform.
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evolution of Kink Bands and tilt boundaries in block copolymers at large shear strains
Macromolecules, 2000Co-Authors: Lei Qiao, Karen I WineyAbstract:The evolution of Kink Bands and Kink band boundaries in a prealigned poly(styrene-b-ethylene propylene) lamellar diblock copolymer was investigated by applying steady shear at strains in the range of 1−10 strain units. Boundary morphologies were characterized using transmission electron microscopy. As the shear strain increases, both the Kink Bands and the lamellae within the Kink Bands rotate continuously toward the shearing direction, leading to a decrease in the tilt boundary angle and the Kink band boundary angle. Simultaneously, the nature of the Kink band boundary transforms. The chevron boundaries present at low strains, and thus large tilt angles, become omega boundaries as the strain increases to ∼3 strain units. At higher strains (∼5 strain units), the tilt angle further decreases, and the omega boundaries start to break, preferentially in the PS microdomains. Delamination of the PS microdomains was also observed at the highest strain amplitude (10 strain units), which was associated with the li...
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Controlling Kink band morphology in block copolymers : Threshold criteria and stability
Macromolecules, 1998Co-Authors: Daniel L. Polis And, Karen I WineyAbstract:The initiation, structure, and dynamics of defects control both the structure and physical properties of materials. In this work, Kink band defects are systematically introduced into a lamellar poly(styrene-b-ethylene propylene) diblock copolymer by applying various rates and total strains of steady shear. However, Kink Bands are only produced when the shear strain exceeds a critical value. The mere existence of Kink Bands implies the presence of a preferential slip plane parallel to the lamellae, which we estimate exists within the polystyrene microdomains. Furthermore, our results regarding the dependence of Kink band geometry on shear rate and strain suggest that these defects are formed by the rotation of lamellae. Based on a rotation mechanism, the characteristic size of the Kink Bands and their spatial distribution, it appears that preexisting defects initiate Kink Bands. Insights gained from steady-shear-induced Kink Bands are extended to oscillatory shear alignment of this high molecular weight di...
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Kink Bands in a lamellar diblock copolymer induced by large amplitude oscillatory shear
Macromolecules, 1996Co-Authors: Daniel L Polis, Karen I WineyAbstract:Recent studies have induced a biaxial texture in lamellae-forming poly(styrene-b-ethylene propylene) diblock copolymers by applying large amplitude oscillatory shear. According to small-angle X-ray scattering, this biaxial texture consists of parallel lamellae (normal to lamellae aligned perpendicular to the shearing surfaces) and transverse lamellae (normal to lamellae aligned parallel to the shearing direction). This study determines the arrangement of these two populations of lamellae by using field emission scanning electron microscopy to examine the microstructure and superstructure. The transverse lamellae are separated from the parallel lamellae by sets of parallel wall defects which have two characteristic orientations. This parallel-transverse biaxial morphology shows an astonishing resemblance to that of Kink Bands. The formation of Kink Bands suggests that the transverse lamellae could be the result of buckling in the parallel lamellae. Relaxation of the Kink band superstructure during quiescent annealing occurs primarily by lamellae tilting, rather than twisting, and produces a variety of defect structures.
