Papers by Keyword: Anisotropy Factor

Abstract: An experimental issue of studying the structural and deformation properties of an initially anisotropic 1561 alloy within a wide temperature-rate range is considered. In the course of realization of the experiments on “Gagarin’s” samples cut out in the rolling direction, the circular cross sections of the samples took an elliptical form. As a macro-characteristic of the material reflecting the occurring structural changes, the anisotropy factor is taken, which is represented by the ratio of deformations measured along the small and large axes of the cross section. Previously unknown regularities of the change in the anisotropy factor were established at the temperature increase under different values of the degree and strain rate. An essential dependence of the anisotropy factor on the thermomechanical conditions of deformation is noted. At high homological temperatures, the thermal range corresponding to the manifestation of superplastic properties is identified. Here, the anisotropy index tends to a minimum value. A correspondence between the results of mechanical experiments and the study of the structural state of the alloy was established. The obtained results indicate the dependence of the anisotropy factor on the initial structure of the alloy. The anisotropy factor can be taken as one of the macroparameters of the material that correspond to structural transformations and allow one to quantify the degree and completeness of structural changes relative to the initial state in a changing field of temperatures and strain rates.

Abstract: We present first-principles investigations on the elastic properties of XBi (X=Ho, Er) compounds. Basic physical properties, such as lattice constant, elastic constants (C_ij), isotropic shear modulus (G), bulk modulus (B), Young’s modulus (Y), Poisson’s ratio (υ), and Anisotropy factor (A) are calculated. The calculated energy band structures show that the two compounds possess semi-metallic character. We hope that these results would be useful for future work on two compounds.

Abstract: Abstract. The dose calculation parameters of ¹⁰³Pd radioactive seed need to be determined strictly before clinical application for tumor implanted treatment. The radial dose function and the anisotropy factor are data analyzed and nonlinear fitted based on the value of dose parameters in American Association of Physicists in Medicine (AAPM) TG-43 and TG-43U1 by Cftool and SFTool toolbox in Matlab. Result was selected according to the optimum principle of fitting accuracy that is the coefficient of determination is close to 1 and gets the minimum value of the sum of square of deviations in fitting process. The calculation of the radial dose function and the anisotropy factor result are obtained in an ideal situation, and then the dose calculation of ¹⁰³Pd radioactive seed is determined. The calculation of ¹⁰³Pd radioactive seed provides a theoretical basis for ¹⁰³Pd implanted treatment of tumor in clinical.

Abstract: The flexural/twist anisotropy, present in most balanced, symmetric laminates with angle play layers, have an important influence on elastic instability of plate composite. The maximal compression load can be reduced up to 13% in comparison with the orthotropic plate. The anisotropy changes also the deformation mode form. Based on the finite element studies, we developed an empirical law – the relation between the knockdown factor, the anisotropy factor and the plate geometry. The knockdown factor is defined as the ratio between the maximum loads of the anisotropic plate and of the orthotropic one. In this way, the semi-analytic instability calculation approach is based on analytical linear bifurcation theory with orthotropic properties and on empirical consideration of the flexural/twist anisotropy effect by the knockdown factor.

Abstract: Anisotropy in elastic properties of Ti-24mol%Nb-3mol%Al (TiNbAl), a new biomedical shape memory alloy developed by our group, was characterized in a temperature range from 133K to 413K. A well developed <110>{112}-type recrystallization texture is formed by an annealing at 1273K for 1.8ks after a severe cold-rolling. Young’s modulus of the -phase exhibited a strong anisotropy depending on the loading direction. Young’s modulus along of -phase of TiNbAl around room temperature was estimated to be , with assuming that the texture is perfectly developed.