Tyurin A.I., Pirozhkova T.S., Vorobyov M.O.

TSU named after G.R. Derzhavin

Studies of the physical and mechanical properties and deformation mechanisms of the material of medical and biological applications in the micro- and nanovolume

Medicine is always one of priority direction for the development of humanity. She also incorporates the latest achievements and developments of almost all other sciences (biology, chemistry, pharmacology physics, materials science, computer technology, etc.). At the modern stage of development of medicine the design and application of new materials is particularly intense issue. This is primarily due to an increase in the requirements for the materials used for the production of all kinds of prostheses and implants, as well as other applications (in dentistry, traumatology, orthopedics, etc.). Medical devices are usually used in very extreme conditions when the material is subject to physical, chemical, biological, and other influences. Therefore materials biomedical applications must meet some characteristics a such as chemical and biological inertness, biocompatibility, low specific weight, high mechanical strength (hardness, elasticity, etc.), etc.

Today, such materials include zirconia ceramics, which have superior biocompatibility and high strength properties compared to other materials (metals, metal alloys, polymers, etc.) [1]. However, many of ceramics used in medicine (as dentures, implants, etc.), cause permanent mechanical interaction of the material. In this case, despite the possible large size of the implant or prosthesis mechanical interaction between the various moving parts or between the implant and bone tissue occurs in localized areas of the interaction of contacting surfaces. The behavior of the material, its physical properties and mechanisms of deformation in such interactions still remain unclear until the end [2, 3, 4], especially for advanced nanostructured materials, which include zirconium ceramic. Therefore, the aim was to study the physical and mechanical properties and deformation mechanisms of nanostructured materials biomedical applications of micro-and nano volume.

Method was used for the study of dynamic micro and nanoindentation. The studies were conducted on samples of the nanostructured zirconia ceramics. As the test material used fused quartz. Indentation performed symmetrical triangular impulse loading. The amplitude of the applied force is varied in the range of 1 µN to 1N. It is possible to study the deformation zone from tenths of nanometers to several microns (0.6 nm to 1 micron). The studies were conducted nanotriboindentometre Hysitron TI 950 TriboIndenter.

Knowledge of the real kinetics of the applied load P(t) and the depth of indentation h(t) allows continuous real-time analysis of the rate of deformation as a function of the instantaneous contact stresses, separate different phases of the process, supply analysis, to determine the energy parameters and from these results to talk about micromechanisms displacement of the material under the indenter.

Rebuilding kinetic dependences R(t) and h(t) in typical P(h) diagrams to determine the transition from purely elastic to elastic-plastic deformation and to determine the energy characteristics of the indentation process (input energy, the return energy, the energy absorbed in the formation of a indent, the reduced energy, etc.).

The results show that at depths of up to 2 - 4 nm, the local deformation is entirely elastic, which then h = 4 nm is replaced by the elastic-plastic. So much for the study of ceramics and fused quartz in the range of 16 nm - 1000 nm, the absorbed energy calculations evidence in favor fact that the deformation occurs due to the formation and movement of point defects and low-atomic clusters. LiF single crystals obtained data indicate that the elastic - plastic deformation occurs in several stages: the stage of the deformation mechanisms by monoatomic (3 <h <130 nm), the stage of the dislocation flow (h> 1200 nm) between them (130 <h <1200nm) may be mixed mechanisms of deformation or deformation due to crowdion or low-atomic clusters.

Thus in the work identified micromechanisms of deformation of materials, including materials of medical and biological applications.

References:

1. A. B. Sloboda, A. G. Lezhnev, Traumatology and Orthopedics of Russia, 2011, Vol. 2 (60), pp. 44-49.

2. Anthony C. Fischer-Cripps, Nanoindentation, Springer-Verlag, New York, 2011, 279 p.

3. Y. I. Golovin, Nanoindentation and its possibilities.
M. Engineering, 2009, 312 p.

4. Y. I. Golovin, A. I. Tyurin, Journal of Applied Physics, 2005, Vol. 75, no. 4, pp. 91-95.