The Nature and Multiscale Techniques for Characterization of Mechanical Properties: from Nanostructured Materials to Single Macromolecules. Part II. Strength of Low-Dimensional Materials

The paper analyzes the experimental data on the mechanical properties of low-dimensional objects and materials: film coatings, thin near-surface layers, superlattices, nanopillars, fibers, nanotubes and macromolecules. The dependencies of the hardness, yield stress and strength on the grain size are considered for nanocrystalline materials. The range of applicability of the Hall-Petch ratio and physical factors causing deviations from it are discussed. The dynamics of the behaviour of single molecules under the action of increasing or constant applied force is considered. Estimates of the role of the mechanical properties of biological macromolecules in the functioning of living systems are presented.