V.E. Panin

Spectrum of excited states and the rotational mechanical field in a deformed crystal

The authors discuss, from the standpoint of quantum gauge theory, the plastic deformation of crystals as a process of their structural transformation in regions of strongly excited states and their relaxation by the emission of defects as elements of a new structure. Plastic deformation is considered on the basis of the behavior of inhomogeneous highly nonequilibrium systems which undergo local structural transformations and move toward equilibrium through the motion of elements of new structures in the fields of stress gradients.

Role of local nanostructural states in plastic deformation and fracture of solids

The paper substantiates the concept of physical mesomechanics that the basis for nonlinear behavior of solids under plastic deformation and fracture is the formation of nanostructural states in local highly nonequilibrium zones. Their structural transformations and two-phase decay govern the generation of strain-induced defects and cracks. Nonlinear wave mechanisms of nanostructural states influence on plastic deformation and fracture are discussed.

Formation of periodic mesoband structures in the tension of polycrystals with long boundaries

A study is made of how the mechanism of plastic deformation of polycrystalline low-carbon steel is a ffected by large-scale interface in the form of long localized regions of remelted material extending in the transverse direction. It is shown theoretically and experimentally that oscillating stress mesoconcentrators develop in the neighborhood of such interfaces and that relaxation of these concentrators results in the formation of periodic mesoband structures in deformable polycrystals.

Nonlinear wave processes in a deformable solid as a hierarchically organized system

Theoretical predictions and experiments demonstrate that solid state mechanics should consider, along with a structurally equilibrium 3D crystalline subsystem, a structurally nonequilibrium planar subsystem as a complex of all surface layers and internal interfaces with broken translation invariance. Primary plastic flow of a loaded solid develops in its structurally nonequilibrium planar subsystem as channeled nonlinear waves of local structural transformations that determine the self-organization law of multiscale plastic flow. These waves initiate mesoscale rotational deformation modes, giving rise to all types of microscale strain-induced defects in the planar subsystem. The strain-induced defects are emitted into the crystalline subsystem as an inhibitor of nonlinear waves of plastic flow in the planar subsystem. Plastic deformation of solids, whatever the loading type, evolves in the field of rotational couple forces. Loss of hierarchical self-consistency by rotational deformation modes culminates in fracture of material as an uncompensated rotational deformation mode on the macroscale.

Magnetron deposition of metal-ceramic protective coatings on glasses of windows of space vehicles

Transparent refractory metal-ceramic nanocomposite coatings with a high coefficient of elastic recovery and microhardness on the basis of Ni/Si-Al-N are formed on a glass substrate by the pulse magnetron deposition method. The structure-phase states were investigated by TEM, SEM. It was established that the first layer consists of Ni nanograins with a fcc crystalline lattice, the second layer is two-phase: 5-10 nm nanocrystallites of the AlN phase with the hcp crystalline lattice in amorphous matrix of the Si3N4 phase.

Effect of heat treatment and elastoplastic deformation on magnetic properties of 50Ni2Mo powder steel

The paper studies the effect of heat treatment modes and uniaxial tension on the magnetic properties, internal stress and specific resistance of 50Ni2Mo powder steel. It is shown that when treated and mechanically loaded in the elastic range and weak magnetic fields, the steel reveals anomalous behavior of its magnetic characteristics such as coercive force, maximum permeability and residual induction. The observed anomalous behavior is analyzed in the framework of physical mesomechanics and is associated with porosity of the powder material. It is demonstrated that physical mesomechanics and magnetic measurements hold promise as an efficient tool of research in porous ferromagnetic materials in various effective external fields. The thus studied magnetic characteristics allow efficient control of heat treatment modes of 50Ni2Mo powder steel.

The effect of Al intermediate layer on thermal resistance of EB-PVD yttria-stabilized zirconia coatings on titanium substrate

The yttria-stabilized zirconia coatings sprayed on titanium substrates by the electron beam physical vapor deposition were subjected to thermal annealing in air at 1000°C for 1, 30 and 60u2005min. The delamination and fracture of the coatings are studied by the scanning electron microscopy and X-ray diffraction. It is shown that a magnetron sputtered Al interlayer between the coating and the substrate considerably improves the thermal resistance of ceramic coatings.

Study of fracture toughness of ZrO2 ceramics

The fracture toughness characteristics of ZrO2ceramics were determined experimentally using an original technique of wedging small-sized chevron notch specimens developed at the Institute of Strength Physics and Materials Science SB RAS (Russia) in the laboratory of physical mesomechanics of materials and non-destructive testing. Measurements have shown that inelastic displacements can be more than 22% of the total displacement of the consoles by the time of the specimen failure. The effect of the Y2O3 stabilizer on the critical stress intensity factor KIc was verified. It was shown that an increase in the Y2O3 stabilizer content from 3 to 8% significantly decreases the fracture toughness. The stress intensity factor KIc falls within the range from 5.7 to 2.35u2005MPa m1/2.The fracture toughness characteristics of ZrO2ceramics were determined experimentally using an original technique of wedging small-sized chevron notch specimens developed at the Institute of Strength Physics and Materials Science SB RAS (Russia) in the laboratory of physical mesomechanics of materials and non-destructive testing. Measurements have shown that inelastic displacements can be more than 22% of the total displacement of the consoles by the time of the specimen failure. The effect of the Y2O3 stabilizer on the critical stress intensity factor KIc was verified. It was shown that an increase in the Y2O3 stabilizer content from 3 to 8% significantly decreases the fracture toughness. The stress intensity factor KIc falls within the range from 5.7 to 2.35u2005MPa m1/2.

Modification of Ti-Al-N coatings by high energy (Cr+ + B+) ion bombardment

The effect of the bombardment by high-energy ions Cr+ and B+ on the structure and mechanical properties of TiAlN coatings is investigated. It is found that the wear resistance of coatings decreases by ∼9 times and the microhardness keeps the magnitude at the fluency 2 × 1017 sm−2. It is established by the X-ray analysis method that the amorphization of the surface layer of the coating occurs at the used modes of ionic processing. The secondary ion mass spectrometry and X-ray analysis show that this effect causes an amplification of destruction of the surface layer of the coating under ion bombardment due to the induced crystalline lattice amorphization.

Mechanics of deformation of structurally nonuniform media

It is shown theoretically and experimentally that the complete deformation of structurally nonuniform media consists of two components: macrodeformation, which is determined by the relative displacement of the elements in the structure (grains, subgrains, phases, and so on) as a whole, and microdeformations, which represent the deformations of these elements themselves.