INVESTIGATION OF THE POSSIBILITY OF FORMATION OF VARIOUS TYPES OF ORDERED ALLOYS AND INTERMETALLIDES USING THE EXAMPLE OF CU-PT AND NI-AL ALLOYS

Bi-component alloys, depending on the concentration of the components upon transition from a disordered state on the basis of fcc lattice, can be converted into a large set of superstructures based on fcc, fcc, hcp, bcc, rhombic crystal lattices and others. In each case, similar phase transformations are accompanied by changes in the symmetry of the crystal structure, the manifestation of anisotropy of the physical and physico-mechanical properties of the materials. At the nanoscale, such properties can serve as specific memory elements. Using the example of Cu-Pt and Ni-Al systems alloys, the molecular dynamics and Monte Carlo methods were used to search for possible types of superstructures as a function of temperatures and pressures (comprehensive compression, tension, uniaxial tensile strain, compression). Interactions between different pairs of atoms were specified in potential models based on the first principles. In the case of the NiAl intermetallide, the concentration intervals from stoichiometry in which the bcc crystal lattice is conserved are determined. For this type of intermetallide, the possibility of the existence of a L1₀ superstructure with simultaneous deformations of comprehensive compression and tension in and directions is predicted. For uniaxial deformation strains , the existence of a rhombic superstructure L1₁ is possible.