| The Department | Members | Working paper | Teaching materials | Schoolleaver |
Scientific work
Scientific directions:
1. Mechanical, diffusive properties and relaxation behavior of solids of various faulted structure; 2. Physics in biomaterials.
Scientific achievements (for the last 10 years):
1. There is experimental evidence that rotation effects are not only of great accommodative importance (concern) but these effects also make substantial contribution in plastic deformation. Our received scientific results (go to prove that) point to a significant role of special and near-special grain boundaries in formation of plastic rotations. It was suggested crystal-geometrical model of grain boundaries’ structure that takes account (with consideration of) not only of full match, but also of partial match of atoms in the boundary. By use of the model it was calculated a value of effective energy of the boundary for various disorientation angles and it was also described the nature of low energy in special grain boundaries. It was established a law of formation and development of cracks (splits) in 2-dimensional polycrystalline samples of aluminum with grains of various size and with various types of grain boundaries and it also was determined destruction mechanisms of samples, it was cleared up a question about influence of titanium nitride strengthening covering on the development of relaxation processes and on destruction mechanisms. By use of these scientific results 31 articles were published and 3 Ph.D. thesis were defended (Sakharova N.O., 1999; O.V. Shekhovtsov, 2005; R.V.Shurinov, 2009).
New effects of internal friction and changes in Young’s modulus of alloys were discovered and these changes were connected with structural, phase and kinetic transformations in alloys under the conditions of superplastic effect. It was shown that the impellent of these transformations is structural and phase metastability that occurs in the process of crystallization and due to the mechanical reduction of alloys. It was established that slippage in grain boundaries is not always dominating mechanism of superplastic deformation. From the experiments it was concluded that hydrodynamic deformation mode occurs due to superplastic conditions. Mass transport processes in alloys at the early stages of superplastic deformation are largely determined by amorphized area in grain boundaries that forms in the process of crystallization or in the process of mechanical presetting of the samples. 20 scientific articles about this question area were published at most in abstract journals.
2. It was synthesized unique calcium-phosphate nanomaterials that by their structure, composition and morphology are close to mineral constituent of hard tissue of vertebrates. It was suggested a new model of hydroxyapatite crystallization from amorphous calcium phosphate by its removal from solutions. It was studied the nature and properties of structural changes in hydroxyapatite nanopowders on annealing. It was discovered a new effect of annealing activation of hydroxyapatite pressings caused by influence of impurity. Based on scientific results of studied physical processes during synthesis and annealing of hydroxyapatite it was created ceramic biomaterials with functional properties close to those of natural bones and of adamantine substance of teeth (enamel). Those materials that showed excellent biocompatibility and bioactivity in experimentation on animals were applied in clinical practice; more than 200 orthopedic operations were made (put/carried out). Postoperative research showed that used biomaterials were high-performance artificial hard tissue substitutes and they could be used successfully in further clinical practice. On this subject it was defended Ph.D. thesis (Rokhmistrov D.V., 2009) and 25 scientific articles appreciated by Scopus system were published.