A. N. Men

Property-composition correlations and short-range order in bcc and fcc binary solid solutions

The properties of an ordering solid solution are substantially dependent on the long-range and short-range order parameters; a method is given for representing a binary solid solution as a set of cluster components whose short-range order parameters are incorporated out to the second coordination sphere. The scheme is illustrated via the lattice parameter and Debye temperature for Ti-Mo alloys (bcc lattice) and via the magnetic moment of Fe-Pd alloys (fcc lattice). The method allows one to describe nonmonotonic composition-property relationships and to define the values of properties for ordered structures.

Short-range order in binary alloys taking into account formation of structural domains

A model is proposed for representing microinhomogeneities of disordered alloys as cubic structural domains. The concept of an effective atom introduced in this article made it possible to express the relation between property and composition in terms of property parameters of nearest atom pairs, the domain size, and the short-range parameter of the first coordination sphere α1. Using as an example the concentration dependence of the Young modulus, the thermal linear expansion coefficient, and the magnetic anisotropy constant we have determined the property parameters of atom pairs and the composition dependence of α1 and of the domain size of disordered alloys of the Ni1-cFec, system (0≤c≤0.25).

Calculation of short-range order in the method of cluster components

A scheme is proposed for calculating the short-range order in the method of cluster components for an n-component solid solution, taking into account an arbitrary number of spheres. The calculation of a single-, two-, and three-coordination spheres for a binary system and a calculation of a single sphere for a triple system are considered in detail. In the case of a binary system the possible type of property-composition dependence for a random distribution of the atoms in the case of one, two, and three coordination spheres are analyzed. The method is illustrated using a calculation of the concentration dependence of the elasticity constants of a KIcBr1-c solid solution.

KONZENTRATIONSABHAENGIGKEIT DER AKTIVITAETEN DER CLUSTERKOMPONENTEN VON GRANAT-MISCHKRISTALLEN

Ein Clusterkomponentenmodell wird fur Mischkristalle mit Granatstruktur und 3 kationischen Subgittern entwickelt.