Advanced Materials Research Vol. 1013

Abstract: In the paper we consider the size effect of the closed structural formations as the function of accumulation of scalar density dislocations and their components under plastic deformation. The focus is on the role of interfaces of different types. The sizes are determined and the various parameters of the structure defining the micro-and mesolevel are identified at the development of the mechanisms of plastic deformation. The role of statistically stored dislocations (SSD) and geometrically necessary dislocations (GND) in the formation of the defect structure of the material is examined. It has been established that the smaller the size of the closed structure, the greater the GND part and the smaller the SSD component. The work is based on the TEM research of the structure of deformed materials.

Abstract: Processing through the application of severe plastic deformation (SPD) leads to very significant grain refinement with grains that are typically in the submicrometer or even the nanometer range. These ultrafine-grained (UFG) materials provide an opportunity for achieving exceptional flow properties including high strength at ambient temperature and, if the very small grains are reasonably stable, superplastic elongations at high testing temperatures. These flow characteristics are examined for materials processed using the two SPD procedures of equal-channel angular pressing (ECAP) and high-pressure torsion (HPT).

Abstract: In the present study the effect of second γ'-phase particles which do not undergo martensitic transformation on the functional properties – shape memory effect and superelasticity, in ferromagnetic FeNiCoAlX (X = Ta, Nb, Ti) and NiFeGaCo single crystals are investigated. Dispersed γ'-phase particles allow to control both mechanical and functional properties due to variation of chemical composition, volume fraction and size of nanoparticles, and to obtain the nanocomposites with complex of necessary properties.

Abstract: Effect of a size of closed structural formation on accumulation of dislocation density and its components at plastic deformation is studied. Main attention is given to a role of a division of boundaries of a different type. Structural formation sizes are determined and different parameters of structure defining micro-and mezolevel at development of plastic deformation mechanisms are distinguished. A role of statistically stored dislocations (SSD) and geometrically necessary dislocations (GND) for defect structure formation of a material is examined. It is determined that than a size of closed structural formation is less than that a component of GND is larger and component of SSD is less. The work is based on results of TEM reserches of a structure of deformed materials.

Abstract: In this paper the study of structural characteristics of the coarse-crystalline Ni₃Al alloy deformed by cold-rolling at a room temperature is presented. The research was carried out by the X-ray methods. It is established that plastic deformation leads to an increase in lattice strain, causes disturbance of a grain structure and order-disorder phase transition. Lowering the long-range order degree of the alloy is accompanied by inhomogeneous decrease in the antiphase domains sizes. Heterogeneity of the order - disorder transformation is connected with strain localization.

Abstract: It is shown how action of the directed laser radiation leads to formation of column educations in cement MgO system – MgO – H3BO₃ – H₂O. Are considered from feature of structurization in the metal and nonmetallic systems hardening by cooling and hardening of fusions from positions of ap-plication of ideology of hierarchical structures.

Abstract: The results of the analysis of phase equilibria ordered phases in binary systems based on palladium Pd-Me (Me = Co, Rh, Ir, Cu, Ag, Au, Ni, Pt) are set out to search for correlations and crystal-chemical and crystal geometric factors. It is found that the packing factor in disordered solid solutions in binary systems based on Pd is close to the value of 0.74 on a background of a slight deviation from the atomic volumes Xena. It is revealed that increasing of the hydrogen permeability in Cu-Pd binary alloys correlates with significant reduction of the packing factor in B2 ordered phase in the range of 40 at.% Pd. It is found that various structural-phase states are formed in Pd-Me binary systems with certain combinations of temperature and size factors.

Abstract: This paper presents the results of a study of stress relaxation in Ni₃Ge single crystals with the L1₂ structure oriented along the [001] axis. The anomalous temperature dependence of the strain rate at relaxation has been determined.

Abstract: The dislocation structure and mechanical properties of Ni₃Fe single crystals with the short range order were investigated. The laws of the dislocation structure evolution of single crystals at different deformation axis orientations were analysed. Correlation of the dislocation structure evolution with the deformation stages for the single crystals with the deformation axis orientations [001], [11], [011] and [1.8.12] was established. The role of the slipping plane numbers in the substructure evolution was revealed.