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.

Study of thermal expansion and thermal conductivity of cemented WC–Co composite

Abstract: Thermal properties are important to the cemented tungsten carbide product design and the product life. In this study, the thermal expansion and thermal conductivity of WC–Co material were measured using dilatometry and laser flash methods respectively. The effects of cobalt content, WC grain size and magnetic saturation (MS) on the thermal properties of cemented tungsten carbide were investigated. The results show that coefficient of thermal expansion (CTE) of WC–Co is strongly dependent on cobalt content. Grain size and MS have no clear effects on CTE. In contrast, the thermal conductivity of WC–Co is affected by all the factors. Larger grain size and less cobalt lead to higher thermal conductivity. High magnetic saturation increases thermal conductivity. The correlation equations of CTE/thermal conductivity as a function of WC grain size/cobalt content are proposed and discussed in the study. By considering the effects of WC/Co interface on the thermal properties, both thermal expansion and thermal conductivity of WC–Co materials can be explained using the rule of mixture principle.

Structure and properties of silica containing aluminum and phosphorus near the AlPO4 join

Abstract: Refractive index, density and thermal expansion have been measured for the system Al 2 O 3 P 2 O 5 SiO 2 near the AlPO 4 join. The silica content varies from 100% to 78% with molar ratios of aluminum to phosphorus varying from 0.5 to 2.0. As the join is approached at constant silica content, the three properties decrease. The refractive index drops below that of pure silica while the mass density is slightly higher. Thermal expansion reaches a minimum at the join. Along the AlPO 4 join, as the AlPO 4 content increases, the index and thermal expansion decrease linearly, the mass density increases slowly and the molar density, assuming an ideal mixture of AlPO 4 SiO 2 , remains invariant. Previous work has theorized the formation of AlO 2 PO 2 structural units which replace two SiO 2 units. The shape of the isofracts supports this view and implied that AlPO 4 units are formed with near complete efficiency, containing almost all available aluminum and phosphorus cations. This material is thus much like silica in terms of refractive index, density and thermal expansion but requires a lower processing temperature.

Thermomechanical and thermo-optical properties of the LiCaAlF 6 :Cr 3+ laser material

Abstract: Measurements of the intrinsic thermomechanical and thermo-optical properties of the new laser material LiCaAlF6:Cr3+ (known as Cr:LiCAF) are performed. Thermal diffusivity, heat capacity, thermal expansion, elastic constants, fracture toughness, and dispersion and temperature variation of the refractive index are all characterized for this material. In addition, the magnitude of the thermal lensing induced in a flash-lamp-pumped laser rod of Cr:LiCAF is measured and compared with the results obtained for an alexandrite laser rod in the same laser head. We find that the thermal lensing of Cr:LiCAF is favorably small and that the thermomechanical properties are expected to be adequate for applications at low and medium average power.