Nanoindentation and Mechanical Properties of Materials at Submicro- and Nanoscale Levels: Recent Results and Achievements

The review is dedicated to characteristics of the mechanical behavior of various materials at submicro- and nanoscale levels. To a large extent, progress in this area is determined by the development of a large family of methods for precision force nanotesting, which have been referred to as "nanoindentation". However, nanomechanical properties are studied to date not only and not so much by nanoindentation methods in narrow sense, i.e., the methods of local deformation of macro-, micro-, and nanoscale objects. Force nanomechanical testing is interpreted more broadly and includes the application of small forces to the test object and the precise measurements of deformation with nanometer resolution under uniaxial compression, tension, bending, shear, and torsion by various methods with simultaneous in situ registration of their microstructural parameters by electron microscopy and X-ray diffraction methods. The main research directions developed in the last decade to improve experimental approaches and the results on single-, micro-, and nanocrystalline materials, composites, films, and coatings obtained by means of these approaches in amorphous solids and biomaterials (tissues, living cells, and macromolecules) are described. Particular attention is paid to size effects and atomic deformation/fracture mechanisms at the nanoscale. This review is a natural continuation and development of the author's review published in Phys. Solid State, vol. 50, issue 12, p. 2113 (2008), in which the specifics of the nanomechanical properties of solids are analyzed, and describes both the basic concepts of nanomechanical testing of materials and the latest advances in this area.