The paper studies the localization of plastic deformation and fracture in a material with a porous coating. A dynamic boundary value problem in the plane strain formulation is solved. The numerical simulation is performed by the finite difference method. The composite structure corresponds to the experimentally observed one and is specified explicitly in the calculation. A generation procedure of the initial finite-difference grid is developed to describe the coating structure with adjustable porosity and geometry of the substrate-coating interface. Constitutive equations for the steel substrate include an elastic-plastic model of an isotropically hardening material. The ceramic coating is described by a brittle fracture model on the basis of the Huber criterion which accounts for crack nucleation in triaxial tension zones. It is shown that the specific character of deformation and fracture of the studied composite results from the presence of local tensile regions in the vicinity of pores and along the coating-substrate interface, in both tension and compression of the coated material. The interrelation between inhomogeneous plastic flow in the steel substrate and crack propagation in the coating is studied.

The theory of structural transformations in the planar sybsystem (surface layers and internal interfaces) of solids under plastic deformation is developed. The theory is based on a consideration for local curvature of the crystal lattice, with new structural states arising in its interstices, responsible for plastic distortion. To satisfy the superplastic condition, such high-rate mechanisms should develop in both planar and 3D crystal subsystems. In a translation-invariant crystal, this condition is met by concentration fluctuations. The multiscale criterion of superplasticity is formulated based on the scale invariance of plastic deformation of the planar and crystal subsystems in a deformable solid. Beyond the criterion, superplasticity passes to the creep mode with restricted plasticity of the material.

В учебном пособии представлена современная научная информация о возможностях атомно-силовой и электронной сканирующей микроскопии. Приведены характерные особенности методик атомно-силовой микроскопии, которые позволяют получать дополнительную информацию о ее свойствах. В частности рассмотрены режим фазового контраста, метод Зонда Кельвина, метод латеральных сил. Рассмотрены принцип работы электронного сканирующего микроскопа и примеры реализации различных методик для исследования микроскопических объектов электролитического происхождения. В частности, продемонстрированы методические приемы получения изображений, позволяющие однозначно идентифицировать габитус микрокристаллов, а также способы получения изображений из внутренних поверхностей полостей микрокристаллов.