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Srikanth Vedantam

Bio: Srikanth Vedantam is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Grain boundary & Shape-memory alloy. The author has an hindex of 19, co-authored 62 publications receiving 1220 citations. Previous affiliations of Srikanth Vedantam include National University of Singapore & Massachusetts Institute of Technology.


Papers
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TL;DR: In this paper, the effect of grain size on the tensile properties of Mg-3%Al alloys at elevated temperatures was investigated by XRD, field emission scanning electron microscope (FESEM) and optical microscope.
Abstract: In this study, we experimentally investigate the effect of grain size on the tensile properties of Mg–3%Al alloys at elevated temperatures. Bulk nanostructured Mg–3%Al alloys were prepared by mechanical alloying followed by conventional sintering and extrusion. The microstructure and grain size were investigated by XRD, field emission scanning electron microscope (FESEM) and optical microscope. The formation of second phase particles was observed in nanostructured powder and the extruded bulk samples. Tensile tests were performed at elevated temperatures up to 250 °C and the yield strength, tensile strength and elongation to failure were measured for microcrystalline and nanocrystalline samples. Remarkably, the strain to failure was observed to be non-monotonic with temperature with the failure strain increasing up to a critical temperature and decreasing thereafter. This critical temperature was found to be strongly dependent on grain size. This phenomenon is attributed to a competition between uniform elongation and necking deformation. The latter dominates at higher temperatures due to decreased strain hardening, particularly in the fine grained samples.

26 citations

Patent
17 Jan 2002
TL;DR: In this article, the upper and lower halves of the inner barrel of a turbine are bolted to one another along a horizontal midline joint with metal-to-metal surface contact.
Abstract: Upper and lower halves of the inner barrel of a compressor for a turbine are bolted to one another along a horizontal midline joint with metal-to-metal surface contact. Elongated grooves are provided in the engaging surfaces, with the upper groove having a depth greater than the depth of the lower groove. Elongated seals are provided in the grooves, including an elongated shim with a metallic woven covering on opposite sides, and margins having sealing edges. The depth of the seal is equal to or less than the depth of the upper groove and an adherent material maintains the seal in the upper groove during installation. In operation, the adherent material dissolves at temperatures above ambient and the seal drops by gravity to bear against the walls of the grooves in response to high pressure air leaking through any gap at the horizontal midline joint.

24 citations

Journal ArticleDOI
TL;DR: In this paper, a phase-field model for grain growth in the presence of mobile second-phase particles is presented. But the model is restricted to a one-dimensional axisymmetric setting.

23 citations

Journal ArticleDOI
TL;DR: In this paper, the authors synthesized and studied functionally graded multilayered Cu/B4C/graphite hybrid composites and compared the properties of the layer-graded composites with those of single layer composites of two different particle sizes.
Abstract: In this article, we synthesized and studied functionally graded multilayered Cu/B4C/graphite hybrid composites. Two classes of layer-graded composites were considered: pure Cu layer with two layers consisting of different particle sizes and uniform particle volume and a pure Cu layer with a single additional layer. The properties of the layer-graded composites were compared to those of single layer composites of two different particle sizes (1–20 µm and 60–90 µm). The composites were tested for compression strength, flexural strength, hardness, density, and wear and braking performance at a range of sliding speed conditions (5, 10, 30, and 35 m/s). The microstructure of the interfaces in the layer-graded composites was characterized to determine the quality of bonding. We found that the layer-graded composites possess improved compression and flexural strength due to lower porosity and residual compressive stress in the composite layer aided by the work-hardening of the Cu layer. The presence of the ducti...

20 citations

Patent
09 Jan 2003
TL;DR: In this paper, the upper and lower halves of the inner barrel of a turbine are bolted to one another along a horizontal midline joint with metal-to-metal surface contact, and an inner woven metal core surrounded by an annular silica fiber layer, in turn surrounded by a metal foil with an outer protective covering of a braided stainless steel.
Abstract: Upper and lower halves of the inner barrel of a compressor for a turbine are bolted to one another along a horizontal midline joint with metal-to-metal surface contact. Elongated grooves are provided in the margin of one of the barrel halves. Elongated composite tubular woven seals are provided in the grooves, the seals having a diameter in excess of the depth of the grooves. The seals comprise an inner woven metal core surrounded by an annular silica fiber layer, in turn surrounded by a metal foil with an outer protective covering of a braided stainless steel. Upon joining the upper and lower halves, the compliant seal is crushed within the groove, maintaining a seal between the barrel halves in the event of warpage of the compressor casing during turbine operation.

20 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: In this article, the authors introduce the concept of diffuse interfaces, the phase-field variables, the thermodynamic driving force for microstructure evolution and the kinetic phasefield equations are discussed.
Abstract: The phase-field method has become an important and extremely versatile technique for simulating microstructure evolution at the mesoscale. Thanks to the diffuse-interface approach, it allows us to study the evolution of arbitrary complex grain morphologies without any presumption on their shape or mutual distribution. It is also straightforward to account for different thermodynamic driving forces for microstructure evolution, such as bulk and interfacial energy, elastic energy and electric or magnetic energy, and the effect of different transport processes, such as mass diffusion, heat conduction and convection. The purpose of the paper is to give an introduction to the phase-field modeling technique. The concept of diffuse interfaces, the phase-field variables, the thermodynamic driving force for microstructure evolution and the kinetic phase-field equations are introduced. Furthermore, common techniques for parameter determination and numerical solution of the equations are discussed. To show the variety in phase-field models, different model formulations are exploited, depending on which is most common or most illustrative.

782 citations

Journal ArticleDOI
TL;DR: The definition of superhydrophilic substrates has not been clarified yet, and unrestricted use of this term to hydrophilic surfaces has stirred controversy in the surface chemistry community.
Abstract: The term superhydrophilicity is only 11–12 years old and was introduced just after the explosion of research on superhydrophobic surfaces, in response to the demand for surfaces and coatings with exceptionally strong affinity to water. The definition of superhydrophilic substrates has not been clarified yet, and unrestricted use of this term to hydrophilic surfaces has stirred controversy in the last few years in the surface chemistry community. In this review, we take a close look into major definitions of hydrophilic surfaces used in the past, before we review the physics behind the superhydrophilic phenomenon and make recommendation on defining superhydrophilic surfaces and coatings. We also review chemical and physical methods used in the fabrication of substrates on surfaces of which water spreads completely. Several applications of superhydrophilic surfaces, including examples from the authors' own research, conclude this review.

702 citations

Journal ArticleDOI
TL;DR: A review of superhydrophobicity and related phenomena induced by surface micro-and nanostructuring is provided in this paper, where the classical approaches to superhydophobicity using the Young, Wenzel, and Cassie-Baxter models for the contact angle (CA) are presented.
Abstract: This paper provides a review of superhydrophobicity and related phenomena (superoleophobicity, omniphobicity, self-cleaning) induced by surface micro- and nanostructuring. The classical approaches to superhydrophobicity using the Young, Wenzel, and Cassie–Baxter models for the contact angle (CA) are presented. After that, the issues that are beyond the Wenzel and Cassie–Baxter theories are discussed, such as multiscale effects, 1D vs. 2D interactions, the effects of contact line, size of roughness details, curvature, and CA hysteresis dependence on roughness. New potential applications of superhydrophobicity are reviewed, such as new ways of energy transition, antifouling, and environment-friendly manufacturing.

557 citations

Journal ArticleDOI
TL;DR: In this paper, the authors introduce the formalism and models for implementing contact angle hysteresis into relevant physical phenomena, such as sliding drops, coffee stain phenomenon (in general evaporative self-assembly), and curtain and wire coating techniques.
Abstract: Contact angle hysteresis is an important physical phenomenon. It is omnipresent in nature and also plays a crucial role in various industrial processes. Despite its relevance, there is a lack of consensus on how to incorporate a description of contact angle hysteresis into physical models. To clarify this, starting from the basic definition of contact angle hysteresis, we introduce the formalism and models for implementing contact angle hysteresis into relevant physical phenomena. Furthermore, we explain the influence of the contact angle hysteresis in physical phenomena relevant for industrial applications such as sliding drops, coffee stain phenomenon (in general evaporative self-assembly), and curtain and wire coating techniques

533 citations