Tungsten elastic moduli

Tungsten disulfide nanotubes 2 PMMA Elastic modulus 2100% Reddy et al. 

In these expressions, E and V denote the elastic modulus and volume fraction, respectively, and the subscripts c, m, and p represent composite, matrix, and particulate phases, respectively. Figure 16.3 plots upper- and lower-bound c-versus-Vp curves for a copper-tungsten composite, in which tungsten is the particulate phase experimental data points fall between the two curves. Equations analogous to 16.1 and 16.2 for fiber-reinforced composites are derived in Section 16.5. 

Tensile and shear forces are not the only types of loads that can result in deformation. Compressive forces may as well. For example, if a body is subjected to hydrostatic pressure, which exists at any place in a body of fluid (e.g. air, water) owing to the weight of the fluid above, the elastic response of the body would be a change in volume, but not shape. This behavior is quantified by the bulk modulus, B, which is the resistance to volume change, or the specific incompressibihty, of a material. A related, but not identical property, is hardness, H, which is defined as the resistance offered by a material to external mechanical action (plastic deformation). A material may have a high bulk modulus but low hardness (tungsten carbide, B = 439 GPa, hardness = 30 GPa). 

FIGURE 1.10. Shear modulus G, bulk modulus K, Young s modulus E, and Poisson s ratio v of tungsten vs. temperature, as calculated fium single-crystal elastic constants (Gj, E, and v ) [1.31], and from measurements on polyciystalline tungsten (G, K, E, and Vj). [1.30] Taken from Metals Handbook [1.40]. o... 

Tantalum is a gray, very hard, malleable, and ductile metal, with an atomic mass of 180.95 and atomic number 73 (Merck Index Online 2002). The boiling point of 5429°C and a melting point of 2996 °C are exceeded only by those of rhenium and tungsten (Hammond 1986, Merck Index Online 2002). Numerous forms of tantalum exist, including pentachloride, pentafluoride, and pent-oxide salts, which are insoluble in water. The most stable oxidation state is + 5. Tantalum is almost twice as dense as iron (density 16.6 gcm ) and about 90% as stiff, with a modulus of elasticity value, E = 2.7x10 psi (Taylor 1969, Merck Index Online 2002). 

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