DEFORMATION, STRUCTURE AND PROPERTIES OF CERAMICS AND CRYSTALS OF HIGH-T(C)-SUPERCONDUCTORS

Data are reported on the deformation and structure of YBa2Cu3O7-x cera mics and single crystals, and other high-T(c) metal-oxides at T congru ent-to 77-1200 K, and the data on the microhardness of single crystals of various compositions are compared. The activation parameters of th e deformation processes are estimated under crystal indentation. The e ffect of oxygen content on the mechanical properties of ceramics and s ingle crystals is commented on and the role of dislocations in the def ormation of ceramic crystallites and single crystals is discussed. A c onclusion is drawn about the determinant role played by the processes of grain boundary glide and crack formation at the deformation of cera mic samples. Finally, the first results from studies of the mechanical properties of a new class of materials-fullerites C60-are reported.