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.

Effect of temperature on thermal properties of high-strength concrete

Abstract: For use in fire resistance calculations, the relevant thermal properties of high-strength concrete (HSC) were determined as a function of temperature. These properties included the thermal conductivity, specific heat, thermal expansion, and mass loss of plain and steel fibre-reinforced concrete made of siliceous and carbonate aggregate. The thermal properties are presented in equations that express the values of these properties as a function of temperature in the temperature range between 0 and 1,000°C. The effect of temperature on thermal conductivity, thermal expansion, specific heat, and mass loss of HSC is discussed. Test data indicate that the type of aggregate has a significant influence on the thermal properties of HSC, while the presence of steel fiber reinforcement has very little influence on the thermal properties of HSC.

Viscoelastic model for the plastic flow of amorphous solids under energetic ion bombardment

Abstract: Under energetic ion bombardment, amorphous solids show substantial plastic flow in the form of anisotropic growth. This is attributed to the relaxation of shear stresses coupled to the thermal expansion in cylindrical thermal spikes induced by intense electronic excitations and to the subsequent freezing-in of the associated strain increment upon cooling down. An asymptotic growth rate at high electronic stopping power and low irradiation temperature is derived which correlates the growth rate with a few simple material parameters without introducing any adjustable free parameter. Good agreement with measurements justifies the basic assumptions of the model.

Phonon density of states and negative thermal expansion in ZrW2O8

Abstract: Thermal expansion of solids arises from anharmonic lattice dynamics. The contrasting phenomenon of negative thermal expansion (NTE)—where expansion occurs on cooling rather than heating—was discovered1 in ZrW2O8 in 1968. Recently, this material has attracted interest in the context of NTE for several reasons: the magnitude of the effect is relatively large (−9 p.p.m. K−1); the temperature range over which NTE occurs is also large (from close to absolute zero up to the decomposition temperature of about 1,050 K); and the NTE effect is isotropic2, evidenced by the fact that ZrW2O8 remains cubic at all temperatures. These characteristics make ZrW2O8 an important system in which to study unusual lattice dynamics of this type, and potentially well suited for application in composite materials with an engineered thermal expansion coefficient3. Here we report neutron-scattering measurements of ZrW2O8 that allow us to investigate its phonon spectrum, and hence determine the energy scale for the lattice motions governing NTE. We find that NTE can be modelled by several low-energy phonon modes, suggesting that the effect arises from the unusual crystal structure of ZrW2O8, which supports highly anharmonic vibrational modes.