Infinite Continuum Research Articles

Theoretical Analysis of the Effect of Substitutional Point Defects on Thermal Expansion

A thermal-expansion theory has been derived for primary solid-solution binary alloys treating the solute atoms as elastic spheres imbedded in an infinite elastic continuum and considering the interactions between the thermal expansion of these point defects and the matrix. The theory predicts that the thermal-expansion coefficient of the alloy can be determined from the thermal-expansion coefficients and the elastic constants of the constituents, and from the atomic volume of the solute atom. The theory is verified for various alloys in the temperature and composition ranges consistent with the assumptions of the theory; i.e., for temperature and composition ranges which obey the Grueneisen law of thermal expansion for the pure components and for the alloy.

Structure des joints de grains dans les metaux purs calcul de l'energie intergranulaire

In a pure metal, the tegion between two adjacent grains, the grain boundary, is constituted by a transition lattice. The structure of the latter is a result of the crystal deformation of each grain: due to this deformation, the displacement of the atoms tends to re-establish the crystallographic planes the most densely packed. This deformation can be calculated by comparing it to that existing in an infinite planar continuum from which we can deduce an evaluation of the intergranular energy. This method is applicable to various types of joints especially to those involving a tilt boundary of small or large amount of misorientation as well as twist boundaries.