Topic
Thermal expansion
About: Thermal expansion is a research topic. Over the lifetime, 21040 publications have been published within this topic receiving 349407 citations. The topic is also known as: heat expansion.
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TL;DR: Grain size-microcracking trends in the three pseudobrookite oxides MgTi2O5, Fe2TiO5 and Al2 TiO5 were examined in this paper.
Abstract: Grain size-microcracking trends are examined in the three pseudobrookite oxides MgTi2O5, Fe2TiO5, and Al2TiO5. These trends are toward smaller critical grain sizes, lower elastic moduli, and lower strengths with increased thermal expansion anisotropy. Extension of an energy criterion relates the micro-cracking transition to the inverse square of the maximum difference in single-crystal thermal expansion coefficients, Δαmax-2.
241 citations
TL;DR: In this article, an aluminum carbide (Al4C3) nanostructure at the end of the MWCNTs, incorporated in the Al matrix, was produced by appropriate heat-treatment.
239 citations
TL;DR: It is shown that the contrasting temperature dependence of the Raman-active mode A(1g) in MoS2 and MoSe2 arises essentially from the difference in their strain-phonon coupling.
Abstract: We report the temperature-dependent Raman spectra of single- and few-layer MoSe2 and WSe2 in the range 77–700 K. We observed linear variation in the peak positions and widths of the bands arising from contributions of anharmonicity and thermal expansion. After characterization using atomic force microscopy and high-resolution transmission electron microscopy, the temperature coefficients of the Raman modes were determined. Interestingly, the temperature coefficient of the A22u mode is larger than that of the A1g mode, the latter being much smaller than the corresponding temperature coefficients of the same mode in single-layer MoS2 and of the G band of graphene. The temperature coefficients of the two modes in single-layer MoSe2 are larger than those of the same modes in single-layer WSe2. We have estimated thermal expansion coefficients and temperature dependence of the vibrational frequencies of MoS2 and MoSe2 within a quasi-harmonic approximation, with inputs from first-principles calculations based on density functional theory. We show that the contrasting temperature dependence of the Raman-active mode A1g in MoS2 and MoSe2 arises essentially from the difference in their strain–phonon coupling.
239 citations
TL;DR: In this paper, the authors used the Green-Kubo expression in linear response theory to obtain the thermal conductivity of a perfect crystal β-SiC and showed that the thermal capacity and thermal expansion coefficient are affected very little by point defects.
239 citations
TL;DR: In this paper, the surfaces of low-frequency phonon modes with no distortions of tetrahedra and octahedra were located in wave-vector space and the rigid unit mode interpretation accounts for the weak effect of the 430 K structural phase transition on the negative thermal expansion, provided that disordered phase does not involve formation of and complexes.
Abstract: The negative thermal expansion recently observed over a wide range of temperatures in may be attributed to the existence of low-frequency phonon modes which can propagate with no distortions of the tetrahedra and octahedra, the so-called `rigid unit modes' Using methods developed for the study of similar modes in silicates we have located the surfaces of these modes in wave-vector space The rigid-unit mode interpretation accounts for the weak effect of the 430 K structural phase transition on the negative thermal expansion, provided that the disordered phase does not involve formation of and complexes On the other hand, the crystal structure of the related material is cross braced by pairs of linked tetrahedra and is therefore significantly less flexible In this case a qualitatively different mechanism may be responsible for the negative thermal expansion observed in
237 citations