Elastic modulus

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

Mechanical Properties of Nanometre Volumes of Material: use of the Elastic Response of Small Area Indentations

Abstract: A new, differential method for determining the stiffness of a sub-micron indentation contact area is presented. This allows measurement of elastic modulus as well as plastic hardness, continuously during a single indentation, and without the need for discrete unloading cycles. Some of the new experiments that become possible with this technique, especially at the nanometre scale, are described. We show quantitatively that electropolished tungsten reproducibly exhibits the ideal theoretical lattice strength at small indentation loads.

Evaluation of strains at peak stresses in concrete: A three-phase composite model approach

Abstract: A wide range of concretes was evaluated to explain the reasons for large strain values of high strength concretes (HSCs) at peak stresses under different loading conditions, such as uniaxial compression, uniaxial tension, bending and torsion. To determine the influences of constituents on the stress distributions at the matrix-aggregate interface, around the aggregate and in the matrix close to the aggregate, concrete was considered as a three-phase composite material consisting of a continuous mortar matrix, model aggregate and the interfacial zone between cement and aggregate. The results obtained show that in normal strength concretes (NSCs) i.e. the hard inclusion case, the elastic mismatch of aggregate and matrix is significant and large tangential, radial and shear stresses occur at the interface. However, in both HSCs and lightweight concretes (LCs), the elastic modulus of the aggregate is closer to that of the matrix, and lower tangential, radial and shear stress distributions occur at the aggregate-matrix interface, resulting in these concretes having a much more uniform stress distribution at the interfaces than NSCs. In both HSCs and LCs, tensile stresses occur at the tips of the aggregate (at the poles in the model) perpendicular to the applied stress, and tangential stresses in the matrix close to the interface or at the aggregate surface are larger than those in NSC ones. These imply that the crack will be forced to go through the aggregate and lower strains will develop in ascending branches of these concretes. Based on the model proposed and on additional microstructural studies, it can be concluded that the levels of strains observed at peak stresses under the different loading conditions are as expected.

Fabrication and characterization of SiC-AIN alloys

Abstract: SiC-AIN alloys were prepared by the carbothermal reduction of silica and alumina, derived from an intimate mixture of silica, aluminium chloride and starch. The resulting single-phase SiC-AIN powder was hot-pressed without additives to a high density. The dense bodies had a fine-grained uniform microstructure. The Young's elastic modulus, microhardness, fracture toughness, thermal expansion and thermal conductivity were measured as functions of composition. The creep behaviour of the SiC-AIN alloy was compared with that of silicon carbide.

The elastic modulus of aluminium-lithium alloys

Abstract: Young's modulus measurements have been made on Al-Li alloys containing up to 32 at % lithium, in an attempt to determine the cause of the high modulus that characterizes this potentially important alloy system. In alloys of commercial interest (7–11 at %, 2–3 wt % lithium) the modulus is in the range 79 to 83 GPa, the actual value depending on heat-treatment conditions. The major contribution to this increased modulus arises from lithium in solid solution. The Young's moduli of the Al3 Li and AlLi intermetallic phases are estimated to be 96 GPa and 105 GPa respectively. Additions of magnesium to the Al-Li system produce a small decrease of the modulus, e.g. 4.5 at % (4 wt %) magnesium reduces the modulus by approximately 2 GPa.