Influence of the composition gradient on the propagation of heat pulses in functionally graded nanomaterials

A theoretical model to describe heat transport in functionally graded nanomaterials is developed in the framework of extended thermodynamics. The heat-transport equation used in our theoretical model is of the Maxwell–Cattaneo type. We study the propagation of acceleration waves in functionally graded materials (FGMs). In the special case of functionally graded Si 1− c Ge c thin layers, we point out the influence of the composition gradient on the propagation of heat pulses. A possible use of heat pulses as exploring tool to infer the inner composition of FGMs is suggested.

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Morphology Evolution of Mn-Si Composition Gradient Micro/Nanomaterials Prepared by Oxygen Assisted Chemical Vapor Deposition

Journal of Nanomaterials ◽

10.1155/2018/7547295 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7

Author(s):

Siwei Tang

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Chemical Vapor ◽

Atomic Ratio ◽

Functionally Graded ◽

Composition Gradient ◽

Graded Materials ◽

Manganese Powder ◽

Shape Structure ◽

Manganese Silicide

The micro/nanostructure of manganese silicide (Mn-Si) compounds with various morphologies (nanowires, films, particles, and polyhedron shape structure) has been synthesized through oxygen assisted chemical vapor deposition by changing the stacking geometry of manganese powder. Polyhedrons prepared in the Mn-Si contact area were identified to be chemical composition gradient functionally graded materials which were verified by analyzing atomic ratio of Mn/Si from top to bottom. Evolution of morphology greatly depended on the stacking shape correlated distance from precursor to the substrate, resulting in distinctive growth mechanisms. Main structures on the substrate have been verified to be Mn5Si3 and Mn4Si7 with different Mn stacking in bumps comparing to sole Mn4Si7 with flat surface.

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Tungsten/Copper Functionally Graded Materials: Possible Applications and Processing through the Powder Metallurgy Route

Materials Science Forum ◽

10.4028/www.scientific.net/msf.534-536.1569 ◽

2007 ◽

Vol 534-536 ◽

pp. 1569-1572 ◽

Cited By ~ 2

Author(s):

O. Ozer ◽

J.M. Missiaen ◽

Celine Pascal ◽

Sabine Lay ◽

Jean Marc Chaix ◽

...

Keyword(s):

Powder Metallurgy ◽

Functionally Graded Materials ◽

Functionally Graded ◽

Composition Gradient ◽

Graded Materials ◽

Layer Material ◽

Cu Migration ◽

Sintering Behaviour ◽

Powder Metallurgy Route

Processing of W-Cu graded materials from attritor-milled W-CuO mixtures is described. The powder reduction steps are investigated by TG and XRD analyses and by microstructural observations (SEM, TEM). Sintering of reduced powder with different compositions is analysed by dilatometry. Sintering behaviour of the graded component processed by co-compaction of a 10/20/30wt%Cu multi-layer material is briefly discussed. Liquid Cu migration is observed and smoothes the composition gradient. Perspectives to control this migration are discussed.

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Heat-pulse propagation along nonequilibrium nanowires in thermomass theory

Communications in Applied and Industrial Mathematics ◽

10.1515/caim-2016-0005 ◽

2016 ◽

Vol 7 (2) ◽

pp. 39-55

Author(s):

Antonio Sellitto ◽

Patrizia Rogolino ◽

Isabella Carlomagno

Keyword(s):

Temperature Gradient ◽

Transport Equation ◽

Heat Transport ◽

Pulse Propagation ◽

Heat Pulse ◽

Average Temperature ◽

Temperature Ranges ◽

Heat Transport Equation ◽

Heat Pulses ◽

Theoretical Proposal

AbstractWe analyze the consequences of the nonlinear terms in the heat-transport equation of the thermomass theory on heat pulses propagating in a nanowire in nonequilibrium situations. As a consequence of the temperature dependence of the speeds of propagation, in temperature ranges wherein the specific heat shows negligible variations, heat pulses will shrink (or extend) spatially, and will increase (or decrease) their average temperature when propagating along a temperature gradient. A comparison with the results predicted by a different theoretical proposal on the shape of a propagating heat pulse is made, too.

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A Study on Modified Mechanical and Wear Characteristics of Epoxy-Particulate Filled Homogenous Composites and Their Functionally Graded Materials

Journal of Tribology ◽

10.1115/1.4002543 ◽

2010 ◽

Vol 133 (1) ◽

Cited By ~ 17

Author(s):

Siddhartha ◽

Amar Patnaik ◽

Alok Satapathy ◽

Amba D. Bhatt

Keyword(s):

Theoretical Model ◽

Functionally Graded Materials ◽

Sliding Wear ◽

Functionally Graded ◽

Epoxy Composites ◽

Cement Kiln Dust ◽

Cement Kiln ◽

Graded Materials ◽

Wear Characteristics ◽

Kiln Dust

This article presents the investigations on modified mechanical and wear characteristics of cement kiln dust (CKD) reinforced homogeneous epoxy composites and its functionally graded materials developed for tribological applications. CKD reinforced homogeneous and functionally graded epoxy composites are developed by simple mechanical stirring and vertical centrifugal casting technique, respectively. Mechanical properties of these graded composites are evaluated and compared with those of homogenously filled epoxy composites. Sliding wear tests are conducted over a range of sliding velocities (105–314 cm/s), normal loads (20–40 N), filler contents (0–20 wt %), and sliding distances (0.5–2 km). For this, a pin-on-disk machine and the design of experiments approach using Taguchi’s orthogonal arrays are used. A theoretical model is proposed for estimating the sliding wear rates for homogeneous, as well as graded composites. The results found from the theoretical model so proposed are found to be in good agreement with the experimental values under similar test conditions. This study reveals that the presence of cement kiln dust particles enhances the sliding wear resistance of epoxy resin and the homogeneous composites suffer greater wear loss than the graded composites. scanning electron microscopy micrograph confirms the graded dispersion of CKD particles in the matrix.

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Nonlinear heat-transport equation beyond Fourier law: application to heat-wave propagation in isotropic thin layers

Continuum Mechanics and Thermodynamics ◽

10.1007/s00161-016-0538-6 ◽

2016 ◽

Vol 29 (2) ◽

pp. 411-428 ◽

Cited By ~ 12

Author(s):

A. Sellitto ◽

V. Tibullo ◽

Y. Dong

Keyword(s):

Wave Propagation ◽

Transport Equation ◽

Heat Transport ◽

Heat Wave ◽

Thin Layers ◽

Fourier Law ◽

Heat Transport Equation

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TiB2/AlN/Cu Functionally Graded Materials (FGMs) Fabricated by Spark Plasma Sintering (SPS) Method

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.280-283.1881 ◽

2007 ◽

Vol 280-283 ◽

pp. 1881-1884 ◽

Cited By ~ 5

Author(s):

Song Zhe Jin ◽

Hai Long Zhang ◽

Jing Feng Li ◽

Shu Sheng Jia

Keyword(s):

Spark Plasma Sintering ◽

Functionally Graded Materials ◽

Electrode Materials ◽

Thermoelectric Module ◽

Xrd Analysis ◽

Functionally Graded ◽

Composition Gradient ◽

Graded Materials ◽

Plasma Sintering ◽

Spark Plasma

The TiB2/(TiB2+AlN)/AlN/(AlN+Cu)/Cu functionally graded materials were successfully fabricated via spark plasma sintering (SPS) method, in which a temperature gradient was achieved by using a specially designed mold and different sintering sequences were carried out. XRD analysis and SEM observations were respectively performed upon the TiB2/AlN/Cu composites. The results show that no new phases were introduced into the composites after mechanically milling or SPS process. The layered composites were found to have a dense microstructure, which changes gradually along a composition gradient. The present FGMs are developed as electrode materials of a solar thermoelectric module.

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