Selected by the editorial

Fundamental and applied researches in the field of superplasticity and related phenomena have always been extensively carried out at the Institute for Metals Superplasticity Problems of the Russian Academy of Sciences (IMSP RAS)

Assembling of pseudo-graphene from grain boundaries with structural units 5-7.

Microstructure and superplastic (SP) characteristics of the alloy 1570C subjected to equal channel angular pressing (ECAP) at the temperature of 325°C and subsequent warm rolling (WR) at the same temperature and cold rolling (CR) at room temperature with reductions 86 and 80%, respectively, were compared.

A method for the construction of initial atomic models of nanocrystals with extrinsic dislocations in grain boundaries for molecular dynamics simulations is developed. The method is used to determine atomic structures and energies of grain boundaries in columnar f.c.c. nanocrystals with [112] column axis.

The recrystallization mechanism after ECP was deduced to be similar to that operating during conventional static annealing. The microstructural changes were explained in terms of Joule heating and similar observations for static recrystallization.

Oscillations of kinetic temperature in harmonic triangular lattice with random initial velocities.

Typical TEM structures of pre-quenched 1420-type alloys after HPT (RT, 4 revolutions, P=6GPa) and further annealing

Many questions remain open in the understanding the role of microstructural factors in the acoustic emission (AE) phenomenon occurring in deforming materials. A comparative analysis of AE time parameters in tensile testing of pure aluminum, copper, silver and nickel specimens having very different values of stacking fault energy (SFE) was undertaken in the present work to clarify the SFE effect on the AE signal. Continuous digital wideband recording was used for AE waveform registration, which offers the possibility to avoid the threshold discriminators and to analyze a continuous AE signal generated during plastic deformation mediated by dislocation mechanisms. The power of the AE signal were selected as the descriptive parameters. Following the evolution of dislocation structures, the AE energy parameters were demonstrated to have a similar behavior in all investigated materials, i.e. the AE level increases sharply at the onset of plastic flow and then decays gradually during the uniform strain hardening stage. However, the absolute values of the AE amplitude and energy differ significantly depending on SFE. It was shown unambiguously that in contrast to expectations, the AE energy parameters reduce as the SFE value increases. This effect is discussed qualitatively in terms of the features of dislocation behavior, which are governed by the SFE value.

The movement of oxygen ions in the Al melts under action of a constant electric field is studied by molecular dynamics. The speed and intensity of oxygen ions movement across the melts depends on their concentration.

By the method of molecular dynamics the structural changes in Ni-Al bimetal particles during the passage of shock waves were studied. Investigated the possibility of forming pores near the interphase boundary metals and related effects.

It was processed by electron beams of a surface of a titanium alloy and the increase of fatigue life is established. Scanning and transmission electron microscopy has been used to study the structure of a titanium alloy modified with electron beams and destroyed by fatigue.

Numerical simulation of necking in tension cylindrical sample with simplified elastic-plastic material properties and large deformations. For experimental verification of the calculated data was carried out by sample testing tensile check deformations on the surface of the sample in real time by the method of digital image correlation.

Using transmission electron microscopy (TEM) method, the microstructure and phase composition of nickel based superalloy ZHS32 processed by selective laser melting (SLM) of a powder composition on a monocrystalline substrate and their evolution during heat treatment (HT) and hot isostatic pressing (HIP) by different regimes have been studied. Microstructure of ZHS32 alloy after SLM subjected T2 (a) and T1 (b) vacuum heat treatment is shown on the figure.

Сopper powders with approximately the same average particle size, but with different internal structures and surface morphologies were obtained by electrolytic method in this work. SEM image of surface morphology of powder particles of copper after heat treatment at T = 600°C: sample 1 (a), sample 2 (b) is shown on the figure.

Basing on finite elements method simulations and experiments the stress and strain distributions in surface points of a disk specimen loaded according to the "Brazilian test" (compression of the disk in the diametrical plane) have been studied. The color pattern of the strain distribution εх in the surface of iron sample points: (a) — the initial stage of loading, the (b) — stage preceding the destruction, (c) — stage destruction are shown on the figure.

The effect of severe plastic deformation by high pressure torsion (HPT) on the structure of AK12MMgN-18%SiCp composite alloy was investigated. The secondary electron image and the mapping to this region on the main elements of alloy after post-HPT annealing at 500°C for 2 hours is shown on the figure.

The formation of the bimodal structure in YBa2Cu3O7−x high-Tc superconducting ceramics during high-temperature deformation is considered. Abnormally coarse grains of Y123 ceramics with (a) rectilinear form and (b) curvilinear form is shown on the figure .

New two-phase VT8-based titanium alloy and its mechanical properties are considered. Microstructure of the VT8-20Zr-0.1B alloy after multiple isothermal forging (a) subsequent quenching (b) and ageing (c) is shown on the figure.

Features of the Rehbinder effect consist in a qualitative change of the development of multi-scale damage kinetics in a deformed sample with presence of surfactants , its influence on the fatigue life of pure iron in gigacycle loading conditions associated with qualitative changes in the role of the surface are discussed. An example of fatigue crack initiation as observed by optical microscopy is shown.

The structure of multilayer carbon nanotubes was studied by means of X-ray diffraction and elector microscopy.An example of scanning electron microscopic image of carbon material heated up to 800 °C and following cooling in distilled water is presented. The outlined rectangular zone A contains scrolled structure

The review paper briefly summarizes the principles of grain refinement in f.c.c. and h.c.p. metals and then presents examples of superplastic flow in several different metals processed by SPD (example of the specimens elongation of ZnAl alloy subjected to equal channel angular pressing is presented on the figure)

The paper reports results of investigation that has been carried out on the morphology, particle size, phase composition and the structure of particles deposited from the low-temperature plasma arc discharge on the walls of the vacuum chamber during the spray of a titanium cathode.

SEM images of samples with CNT’s in central part in copper and aluminium.

This paper presents results of a research on the effect of warm rolling on structure and mechanical properties of the low-carbon pipe steel. It is shown that impact toughness at -196 °C in UFG steel is 15 times higher than that in initial FG condition.

Model investigations of new sp2+sp3 carbon phases that can be modeled as a result of partially alignmenting of armchair single-walled carbon nanotubes (SWNTs) using density functional theory (DFT) is performed. As a result of the simulation revealed that there are five stable structures with equivalent atom positions.

We present the results of in-situ studies of evolution of grain boundary misorientations in ultrafine grained (UFG) aluminum alloy Al-4%Cu-0.5%Zr during annealing. It was found that relaxation processes during annealing are accompanied by grain rotation.

A method for refining the profile of quasibreathers in the space of all initial atoms displacements is developed in the framework of the density functional theory. The method is exemplified by the procedure of constructing the discrete breathers in graphane.