Elastic modulus

About: Elastic modulus is a research topic. Over the lifetime, 33153 publications have been published within this topic receiving 810247 citations.

Estimation of single-crystal elastic moduli from polycrystalline x-ray diffraction at high pressure: application to FeO and Iron

Abstract: X-ray diffraction data obtained under nonhydrostatic compression of a polycrystalline sample yield an estimate of the single-crystal elasticity tensor of the material when analyzed using appropriate equations. The analysis requires as input the aggregate shear modulus from independent measurements. The high-pressure elastic moduli of face-centered-cubic FeO, body-centered-cubic iron (a-Fe), and the pressure-induced hexagonal close-packed iron (e-Fe) are obtained. This analysis currently provides the only method of determining single-crystal elasticity tensors in the megabar pressure range and of studying elasticity of very high-pressure phases. [S0031-9007(98)05436-2]

Novel thermodynamically stable and oxidation resistant superhard coating materials

Abstract: A theoretical concept for the design of novel, nanocrystalline and thermodynamically stable materials with hardness of ≥50 GPa (about 5000 kg mm−2), elastic modulus of ≥500 GPa and a high stability against oxidation in air up to 800°C is described together with its experimental verification on several systems nc-MexN/a-Si3N4 (Me  Ti, W, V). The concept is based on avoiding the formation and multiplication of dislocations in the nanocrystalline phase, and blocking the crack propagation in a 0.3–0.5 nm thin amorphous tissue. The theoretical principles of the design of such materials and the thermodynamic criteria for the segregation of the nc- and a-phases, which is necessary for the preparation of such materials, are discussed. Several micron thick films of such materials have been prepared by plasma CVD at a rate of 0.6–1 nm s−1 from the corresponding metal halides, hydrogen, nitrogen and silane at deposition temperatures of ≤550°C. A low content of chlorine of ≤0.3 at.% assures their stability against corrosion in air. Upon microindentation up to a load of ≥100 mN the films show a remarkably high elastic recovery of about 80%. Unlike diamond, c-BN, and C3N4 these materials are thermodynamically stable and relatively easy to prepare.

Physical properties of a single polymeric nanofiber

Abstract: The nanostructural and elastic properties of a single polymeric nanofiber extracted from a nanofibrous scaffold are investigated using atomic force microscopy (AFM). AFM imaging of the nanofibers reveals a “shish-kebab” structure. A portion of the nanofiber is suspended over a microscale groove etched on a silicon wafer. A nanoscale three-point bend test is performed to obtain the elastic modulus. This elastic modulus is found to be 1.0±0.2 GPa for fibers less than 350 nm but decrease with increase in fiber diameter in excess of 350 nm. This is due to the significance of shear deformation as the length to diameter ratio decreases.