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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: Wang et al. as discussed by the authors devised six kinds of periodic planar lattices, which incorporate tailorable coefficient of thermal expansion (CTE) and high specific biaxial stiffness.
Abstract: The unexpected thermal distortions and failures in engineering raise the big concern about thermal expansion controlling. Thus, design of tailorable coefficient of thermal expansion (CTE) is urgently needed for the materials used in large temperature variation circumstance. Here, inspired by multi-fold rotational symmetry in crystallography, we have devised six kinds of periodic planar lattices, which incorporate tailorable CTE and high specific biaxial stiffness. Fabrication process, which overcame shortcomings of welding or adhesion connection, was developed for the dual-material planar lattices. The analytical predictions agreed well with the CTE measurements. It is shown that the planar lattices fabricated from positive CTE constituents, can give large positive, near zero and even negative CTEs. Furthermore, a generalized stationary node method was proposed for aperiodic lattices and even arbitrary structures with desirable thermal expansion. As an example, aperiodic quasicrystal lattices were designed and exhibited zero thermal expansion property. The proposed method for the lattices of lightweight, robust stiffness, strength and tailorable thermal expansion is useful in the engineering applications.

178 citations

Journal ArticleDOI
TL;DR: In this article, the cementite phase of Fe3C was studied by high-resolution neutron powder diffraction at 4.2 and 20 K intervals between 20 and 600 K. The average volumetric coefficient of thermal expansion above Tc was found to be 4.1
Abstract: The cementite phase of Fe3C has been studied by high-resolution neutron powder diffraction at 4.2 K and at 20 K intervals between 20 and 600 K. The crystal structure remains orthorhombic (Pnma) throughout, with the fractional coordinates of all atoms varying only slightly (the magnetic structure of the ferromagnetic phase could not be determined). The ferromagnetic phase transition, with Tc ≃ 480 K, greatly affects the thermal expansion coefficient of the material. The average volumetric coefficient of thermal expansion above Tc was found to be 4.1 (1) × 10−5 K−1; below Tc it is considerably lower (< 1.8 × 10−5 K−1) and varies greatly with temperature. The behaviour of the volume over the full temperature range of the experiment may be modelled by a third-order Gruneisen approximation to the zero-pressure equation of state, combined with a magnetostrictive correction based on mean-field theory.

178 citations

Journal ArticleDOI
TL;DR: In this paper, the relative density of powder composites achieves up to 99% for composites containing 10 to 90 vol.% graphite, and the thermal conductivity increases from 324 to 783 W/m K.
Abstract: 10–90 vol.% of flake graphite is combined with aluminum powders to form aluminum–graphite composites via vacuum hot pressing process. The results show that the relative density of powder composites achieves up to 99% for composites containing 10–90 vol.% graphite. With the increase of flake graphite from 10 to 90 vol.% in the composites, thermal conductivity increase from 324 to 783 W/m K; the coefficients of thermal expansion (CTE) in direction parallel to basal planes of graphite flakes decrease from 16.9 to −2.5 ppm/K, and the CTE perpendicular to basal plane decreases from 15.2 to 10.1 ppm/K. The parallel arrangements of graphite flakes and aluminum lead the thermal conductivity values of composites to agree well with parallel model estimations. The CTE of composites in a-axis agree with rule of mixture estimation representing proportional contribution of the two phases. Along the c-axis of graphite in composites, the CTE are consistent with Turner model estimations indicating that the graphite flake could absorb the expansion from the aluminum phase.

178 citations

Journal ArticleDOI
TL;DR: In this article, the linear thermal expansion of single-crystal and polycrystalline aluminum oxide and poly-crystine thorium oxide was measured from 100° to 1100° K with an interferometric technique.
Abstract: The linear thermal expansion of single-crystal and polycrystalline aluminum oxide and poly-crystalline thorium oxide was measured from 100° to 1100° K with an interferometric technique. For each substance the results are well described by Gruneisen's equation using a Nernst-Linde-mann energy function.

177 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023603
20221,249
2021683
2020742
2019759
2018767