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.

Texture formation in FePt thin films via thermal stress management

Abstract: The transformation variant of the fcc to fct transformation in FePt thin films was tailored by controlling the stresses in the thin films, thereby allowing selection of in- or out-of-plane c-axis orientation. FePt thin films were deposited at ambient temperature on several substrates with differing coefficients of thermal expansion relative to the FePt, which generated thermal stresses during the ordering heat treatment. X-ray diffraction analysis revealed preferential out-of-plane c-axis orientation for FePt films deposited on substrates with a similar coefficients of thermal expansion, and random orientation for FePt films deposited on substrates with a very low coefficient of thermal expansion, which is consistent with theoretical analysis when considering residual stresses.

Thermal expansion of mantle and core materials at very high pressures

Abstract: The thermal expansivities (α) of MgO and high-pressure phases of CaO, CaMgSi2O6, and Fe at ultrahigh pressure are obtained by comparing existing shock compression and temperature measurements to 300 K compression curves constructed from ultrasonic elasticity and static compression data. For MgO, α can be represented by: α = ρoγoCV(ρo/ρ)0.5±0.5/KT where γ is the Gruneisen parameter, CV is the constant volume specific heat, KT is the isothermal bulk modulus, and ρ is the density. Using this expression, the thermal expansivity of MgO is 28-32×10−6K−1 at the pressure of the top of the lower mantle and 10-16×10−6K−1 at its base (at 2000 K). New data for α of e-Fe, together with an inner core temperature of 6750 K, constrain the density of the inner core to be 5±2% less than the density of e-Fe, implying the inner core contains a light element.

Argentophilicity-dependent colossal thermal expansion in extended prussian blue analogues

Abstract: The thermal expansion behavior of isostructural variants of the colossal thermal expansion material Ag3[CoIII(CN)6] has been investigated using variable temperature X-ray and neutron powder diffraction. It was found that substitution at the octahedral transition metal site did not strongly affect the thermal expansion behavior, giving Ag3[FeIII(CN)6] as a new colossal thermal expansion material. Substitution at the Ag site (by D) was shown to reduce the thermal expansion coefficients by an order of magnitude. It was proposed that this correlation between the presence of argentophilic interactions and extreme thermal expansion behavior may explain a variety of thermal effects in flexible framework materials containing metallophilic interactions.

New data on temperature stability and acoustical losses of langasite crystals

Abstract: Refined data of temperature dependences, elastic, dielectric, piezoelectric and thermal expansion coefficients were received for temperature range -100 to 100/spl deg/C. Single and double rotated Z temperature cuts were calculated. Q-factor of LGS resonators was measured in temperature range -200 to 100/spl deg/C.