Möbius Inversion and Mechanical Properties of Ni3Al

1994 ◽  
Vol 364 ◽  
Author(s):  
Nan-Xian Chen ◽  
Mi Li ◽  
Shao-Jun Liu ◽  
Zhao-Duo Chen

AbstractIn this work, a very abstract formula from number theory has been applied to solving the practical problems related to the important industrial material Ni3Al from the microscopic point of view.

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1094
Author(s):  
M. A. Lakhdari ◽  
F. Krajcarz ◽  
J. D. Mithieux ◽  
H. P. Van Landeghem ◽  
M. Veron

The impact of microstructure evolution on mechanical properties in superduplex stainless steel UNS S32750 (EN 1.4410) was investigated. To this end, different thermomechanical treatments were carried out in order to obtain clearly distinct duplex microstructures. Optical microscopy and scanning electron microscopy, together with texture measurements, were used to characterize the morphology and the preferred orientations of ferrite and austenite in all microstructures. Additionally, the mechanical properties were assessed by tensile tests with digital image correlation. Phase morphology was not found to significantly affect the mechanical properties and neither were phase volume fractions within 13% of the 50/50 ratio. Austenite texture was the same combined Goss/Brass texture regardless of thermomechanical processing, while ferrite texture was mainly described by α-fiber orientations. Ferrite texture and average phase spacing were found to have a notable effect on mechanical properties. One of the original microstructures of superduplex stainless steel obtained here shows a strength improvement by the order of 120 MPa over the industrial material.


Hydrocarbon gels contain a number of materials, such as rubber, greases, saponified mineral oils, etc., of great interest for various engineering purposes. Specific requirements in mechanical properties have been met by producing gels in appropriately chosen patterns of constituent components of visible, colloidal, molecular and atomic sizes, ranging from coarse-grained aggregates, represented by sponges, foams, emulsions, etc.; to fine-grained and apparently homogeneous ones, represented by optically clear compounds. The engineer who has to deal with the whole range of such materials will adopt a macroscopic point of view, based on an apparent continuity of all the material structures and of the distributions in space and time of the displacements and forces occurring under mechanical actions. It has been possible to determine these distributions in the framework of a comprehensive scheme in which the fundamental principles of the mechanics of continuous media provide the theoretical basis, and a testing instrument of new design, termed Rheogoniometer, the means of experimental measurement (Weissenberg 1931, 1934, 1946, 1947, 1948).


2013 ◽  
Vol 811 ◽  
pp. 9-13 ◽  
Author(s):  
Zakaria Boumerzoug ◽  
Zakaria Boumerzoug ◽  
Vincent Ji

In this present investigation, the mechanical properties of industrial drawn copper wires have been studied by creep tests, tensile tests and hardness Vickers. The effect of prior heat treatments at 500°C for different time on the drawn wires behavior was the main goal of this investigation. We have found that these heat treatments influenced the creep behavior of drawn wires and recorded shape curves. The creep tests were applied under ambient atmosphere at 240 °C. The creep duration before rupture decreased with the prior heat treatment time. The creep tests results were confirmed by tensile tests. A relationship between the hardness and the ultimate tensile strength of this industrial material has been established. Optical and scanning electron microscopy observations have been also used. Cross section observations of the wire after tensile or creep-rupture tests have shown that the mechanism of rupture was mainly controlled by the void formation.


2009 ◽  
Vol 93 (528) ◽  
pp. 468-475
Author(s):  
Graham Hoare

The German version of Riemann’s Collected Works is confined to a single volume of 690 pages. Even so, this volume has had an abiding and profound impact on modern mathematics and physics, as we shall see. In fifteen years of activity, from 1851, when he gained his doctorate at the University of Göttingen, to his death in 1866, two months short of his fortieth birthday, Riemann contributed to almost all areas of mathematics. He perceived mathematics from the analytic point of view and used analysis to illuminate subjects as diverse as number theory and geometry. Although regarded principally as a mathematician Riemann had an abiding interest in physics and researched significantly in the methods of mathematical physics, particularly in the area of partial differential equations.


2014 ◽  
Vol 624 ◽  
pp. 307-312 ◽  
Author(s):  
Cristina Gentilini ◽  
Elisa Franzoni ◽  
Gabriela Graziani ◽  
Simone Bandini

Rising damp is one of the main issues affecting masonry buildings. However, its consequences on the mechanical performance of masonry structures are not so largely explored. In this paper, the compressive and shear behaviour of masonry triplets, manufactured with solid fired-clay bricks and cement-based mortar, is investigated in dry and moist conditions. The results are interpreted on the basis of the features of the single materials, from both a mechanical and microstructural point of view.


2010 ◽  
Vol 02 (03n04) ◽  
pp. 217-234
Author(s):  
IOANNIS STEFANOU ◽  
JEAN SULEM

The behavior of rock masses is influenced by the existence of discontinuities, which divide the rock in joint blocks making it an inhomogeneous anisotropic material. From the mechanical point of view, the geometrical and mechanical properties of the rock discontinuities define the mechanical properties of the rock structure. In the present paper we consider a rock mass with three joint sets of different dip angle, dip direction, spacing and mechanical properties. The dynamic behavior of the discrete system is then described by a continuum model, which is derived by homogenization. The homogenization technique applied here is called generalized differential expansion homogenization technique and has its roots in Germain's (1973) formulation for micromorphic continua. The main advantage of the method is the avoidance of the averaging of the kinematic quotients and the derivation of a continuum that maps exactly the degrees of freedom of the discrete system through a one-to-one correspondence of the kinematic measures. The derivation of the equivalent continuum is based on the identification for any virtual kinematic field of the power of the internal forces and of the kinetic energy of the continuum with the corresponding quantities of the discrete system. The result is an anisotropic three-dimensional Cosserat continuum.


2016 ◽  
Vol 858 ◽  
pp. 91-97
Author(s):  
Jun Hua Xiao ◽  
Wen Qi Zheng

To investigate the macroscopic mechanical properties of undisturbed structural Xiashu loess in the lower reaches of China’s Yangtze River under triaxial compression, and obtain the intrinsic explanations for the macroscopic mechanical properties from the microscopic point of view, in laboratory, triaxial compression tests were carried out, microstructure images of sheared samples were collected by scanning electron microscope (SEM), and quantitative parameters of microstructure (mainly about particle or pore size, distribution, and alignment) were extracted by digital image processing technique. Based on the test results, the deviator stress-strain relationships of both undisturbed and remoulded Xiashu loess, the structural strength, and the microstructural evolution mechanism about the formation of shear failure zone of Xiashu loess under triaxial compression were analyzed.


Open Physics ◽  
2011 ◽  
Vol 9 (6) ◽  
Author(s):  
Tomáš Ficker ◽  
Dalibor Martišek

AbstractThe 3D profile surface parameter H q and fractal dimension D were tested as indicators of mechanical properties inferred from fracture surfaces of porous solids. High porous hydrated cement pastes were used as prototypes of porous materials. Both the profile parameter H q and the fractal dimension D showed capability to assess compressive strength from the fracture surfaces of hydrated pastes. From a practical point of view the 3D profile parameter H q seems to be more convenient as an indicator of mechanical properties, as its values suffer much less from statistical scatter than those of fractal dimensions.


Author(s):  
Ottorino Ori ◽  
Franco Cataldo ◽  
Mihai V. Putz

Recent advances in graphene studies deal with the influence of structural defects on graphene chemical, electrical, magnetic and mechanical properties. Here the complex mechanisms leading to the formation of clusters of vacancies in 2D honeycomb HD lattices are described by a pure topological point of view, aiming to correlate the variation of specific topological invariants, sensible to vacancy concentration, to the structural evolution of the defective networks driven by the topo-thermodynamical Gibbs free energy. Interesting predictions on defect formation mechanisms add details on the topological mechanisms featured by the graphenic structures with defects. Future roles of bondonic particles in defective HD materials are also envisaged.


2020 ◽  
Vol 309 ◽  
pp. 21-25
Author(s):  
Vlastimil Bilek ◽  
Michal Pešata ◽  
Lukáš Procházka

Pumice is a volcanic rock that consists of a highly vesicular rough textured volcanic glass. It is very porous and shows a high absorption - it can contain a lot of water. Thanks to its low volume density, it is sometimes used as a light natural aggregate, especially for some small elements such as chimney blocks. The paper is focused on the development of concretes and mortars for these purposes. The optimum content of pumice was specified from the point of view of mechanical properties. Special attention was paid to absorbed water - it can be a source of self-curing of concrete.


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