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Formation of the solids’ acoustics department is associated with the name of prof. I.G. Polotskiy — a prominent scientist in the field of physical acoustics. In 1935 I.G. Polotskiy began to research the Ultrasonics in Ukraine and performed a number of original studies of physical and chemical mechanisms of the effect of powerful ultrasonic vibrations on a substance. I.G. Polotskiy organized the ultrasound laboratory at the Metal Metallurgy Institute (Kharkov) in 1940. The effects of ultrasound on the crystallization process of melts had been studied there. In 1952 I.G. Polotskiy together with employees transferred to work into the Laboratory of Metal Physics (Kiev), and then he headed the Department of ultrasonic methods of metal research in the newly created Institute of Metal Physics of AS of the Ukrainian SSR in 1966.

A large amount of fundamental and applied activities had been fulfilled in the department since 1966, the acoustic research methods were developed and pilot setups for studying crystal defects in a wide range of frequencies and temperatures were created. While studying the amplitude-dependent internal friction the regularities of the admixtures influence on the dislocations` mobility were determined, the research methods of metal microdeformation were developed, the energy of dislocations` interaction with atoms of admixtures was calculated (I.G. Polotskiy, T.Ya. Benieva, V.S. Skopin).

Various theories of oscillation damping at the dislocations had been subjected to the experimental verification, which made it possible to determine the parameters of their thermally activated motion in metals with different lattice types (I.G. Polotskiy, G.I. Prokopenko). During the experimental verification of the theory of M.A. Krivoglaz the energy absorption mechanism of elastic vibrations at phase transitions in alloys based on copper and cobalt were determined (I.G. Polotskiy, N.S. Mordyuk).

A cycle of activities devoted to the generation mechanisms of point defects under the impact of strong ultrasound by helium and nitrogen temperatures is known (I.G. Polotskiy, V.F. Belostotskiy). The principles of structural changes, increase in strength and plasticity of refractory metals of VIA group by their processing with ultrasound and low-frequency oscillations were formulated (S.A.Firstov, G.I. Prokopenko).

Using the precision measurements of velocity and damping of elastic waves the critical phenomena in crystals occurred at phase transitions induced by the external influences were studied. The effects of thermocyclic and ultrasonic processing, as well as single-axis compression and alloying on elastic properties of mono- and polycrystalline chromium nearby the Neel temperature was studied (O.I. Zaporozhets).

The activities, connected with the creation and improvement of the experimental base, are constantly carried out in the department. The ultrasonic set-ups / equipment for measurements of velocities and oscillation attenuation within the MHz frequency range (V.F. Taborov, G.I. Prokopenko, O.I. Zaporozhets) and damping at low sound frequencies (V.F.Taborov, V.S. Skopin) have been created. The laboratory variant of multifunctional ultrasonic equipment used for precision researches and diagnostics of metallic materials of nuclear power engineering as well as constructional and functional materials has been developed and produced (O.I. Zaporozhets, N.A. Dordienko, V.A. Mikhailovskiy). The research activity connected with the creation of unique ultrasonic equipment for non-destructive control of material is conducted as well. The set-ups to control the superhard materials and cutting tools, as well as to determine the density of half-finished goods and tungsten wire have been developed and implemented on the enterprises of Ukraine and the Commonwealth of Independent States (UCIS). The methodology and equipment to register the signals of acoustic emission have been created (G.I. Prokopenko, Yu.V. Hanopolskiy, G.I.Kuzmich).The methods, facilities and devices for ultrasonic impact treatment of samples have been created (G.I. Prokopenko, V.P. Krivko, B.N. Mordyuk).

The study of regularities of the behavior of elastic and non-elastic properties of alloys with f.c.c, and h.c.p. lattices and with different type of solid solution decomposition refers to the essential achievements of the department. The regularities have been laid into the basis of new conceptions of acoustic methods usage to study kinetics and staging decomposition of supersaturated solid solutions (T.V.Golub, O.N. Kashevskaya).

The phenomenological theory of acousto-plasticity effect (APE) allowing to describe the amplitude, frequency and velocity dependences of APE, as well as to predict a number of extreme points on temperature and strain rate dependencies of deforming force reduction in an ultrasonic field have been developed (A.V. Kozlov, S.I. Selitser, N.S. Mordyuk).

The dislocation mechanisms of appearing acoustic emission (AE) signals have been researched. The mechanisms were based on a barrier conception of local formation of internal stresses with their further avalanche-like relaxation due to accommodative sliding or formation of microcracks. The mentioned conceptions fully explain the structural sensitivity of parameters AE, dependence of its activity on grain sizes, quantity of second phase particles, stacking fault energy, etc. (L.V. Tikhonov, G.I. Prokopenko).

The effect of a considerable reduction in yield stress of pure metals (Al, Ti, Fe) and some alloys was revealed at multiple impact loading with frequency 1–3 kHz. The rheological model of inelastic behaviour of ductile materials in these conditions was developed (G.I. Prokopenko).

The phenomenon of abnormal mass transfer by multiple impact loading was studied (G.I. Prokopenko, D.S. Hertsriken). During the last years the systematic fundamental researches of structure formation in the surface layers of metallic materials with different types of crystalline lattice by severe plastic deformation caused by high-frequency impact loading using the ultrasonic impact treatment (UIT) were conducted (B.N. Mordyuk, G.I. Prokopenko). The results of these researches were laid into a basis of doctoral thesis of B.N. Mordyuk. It was shown that the main structure forming factor is multiplication and redistribution of dislocations that causes the formation of misoriented cell structures in the conditions of a dynamic recovery or recrystallization accompanied by the increase in concentration of vacancies. An essential role of multisystem twinning and initiated by deformation of phase transformations in formation of ultrafine-grained structures in the materials with the limited amount of sliding systems (h.c.p.–Ti, Zr) was shown. It was determined that the additional factors of grains structure refinement to nano- scale level could be the dispersed particles of the second phase, dispersed powders, implanted into the deformative zone or fine precipitates of phases — the decomposition products of metastable matrix phase.

The phenomenological model of combined ultrasonic impacts which takes into account different micromechanisms of strain hardening was developed. The reduction of the deformative stresses by acoustoplastic effect, under simultaneous action of ultrasound and magnetic and/or electric fields was researched (B.N. Mordyuk). The formation of ultrafine-grained and nano-sized grain structures with the help of high-frequency impact loading (UIT) allows considerably to increase the damping capacity, fatigue strength, hardness, as well as corrosion and wear resistance of different metallic materials (B.N. Mordyuk, G.I.Prokopenko).

The results of the fundamental researches obtained in the department were used as a base for creation of different technologies for strengthening, relaxation processing and plastic forming of constructional materials. Thus, for example, the method of surface strengthening of parts made of titanic alloys, hardened at δ-phase was proposed (G.I. Prokopenko, V.L. Svechnikov). Unlike the traditional technology of metallic rolled tape production the ultrasonic way for wire flatting was suggested and a plant was created, which allowed to produce more qualitative tape with the thickness down to 10 µm, including those made of tungsten and other materials (N.S. Mordyuk, A.V. Kozlov, B.N. Mordyuk).

The team of authors (L.V. Tikhonov, V.A. Kononenko, G.I. Prokopenko, V.A. Rafalovskiy) published a reference book “Mechanical properties of metals” in 1986, in which for the first time the physical-and-mechanical properties were presented in full measure for practically all pure metals and monocrystals, as well as steels, nonferrous and refractory metals and alloys.

The Kurdyumov Institute for Metal Physics and Paton Welding Institute (PWI) of the NAS of Ukraine conducted in the early seventies of the last century the joint activities researching the influence of UIT on the level of residual stresses in welded joints. Later this direction of scientific and applied researches became a base for creation of technology for increasing the fatigue strength of critical welded constructions using the ultrasonic impact treatment. The department in cooperation with Physical-and-Technical Centre of NAS of Ukraine (a corresponding member of NASU V.T. Cherepin, T.A. Krasovskiy) conducts the activities to create an ultrasonic generator and ultrasonic piezoceramic transducers with power output up to 1 kW.

The cooperation with foreign researchers, in particular, with the Edison Welding Institute (Columbus, USA) is developed. A fruitful cooperation of Ukrainian institutes with Canadian company Integrity Testing Laboratory Inc. (ITL) has begun since 1998. A number of partner projects between the ITL and Ukrainian organizations has been fulfilled under the funding of Canadian International Development Agency (CIDA). The methods and equipment for ultrasonic impact treatment were created that favored the progress in distribution of the developments in the whole world. In execution of the activity participated the researchers of Kurdyumov Institute for Metal Physics (G.I. Prokopenko. B.N. Mordyuk) and Paton Welding Institute of NASU (P.P.Mikheev, V.V.Knysh) as well as researchers of the National Technical University of Ukraine “Kyiv Polytechnic Institute” (A.F. Luhovskoi, A.N. Movchanyuk). A pilot sample and later the industrial equipment was developed and produced as a result of the project. The company SINTEC Inc. has organized the assembling of these devices in Canada according to the engineering documentation given by the Ukrainian party. The equipment is used for processing of different constructions and buildings, machines and machinery in different countries of the world — Canada, USA, Italy, Germany, Japan and Australia.

During last years the researchers of the department paid much attention to improvement and development of methods for ultrasonic nondestruction control (US NDT) of materials and constructions of nuclear power engineering. Within the program of NAS of Ukraine “The resource” (2004–2006) the method of control of thermomechanical loadings on separated areas of the reactor vessels of Water-Water Power Reactor type in non-stationary heat conditions was theoretically and experimentally grounded (O.I. Zaporozhets, N.A. Dordienko, V.A. Mikhailovskiy, V.V. Nemoshkalenko, A.I. Nosar, V.B. Molodkin, A.P. Shpak). The method is based on temperature dependencies of elastic modules and appropriate ultrasonic velocities in materials in elastic heterogeneous state.

Within the state nuclear goal-oriented program “ßÌßÐÒ” (2009–2010) the researchers of the department (O.I. Zaporozhets, N.A. Dordienko, V.A. Mikhailovskiy) in association with representatives of the National Science Centre Kharkov Institute of Physics and Technology (NSC KIPT), Ukraine, improved the method of ultrasonic texture diagnostics in plates and tubes of Zr–Nb alloys and other metals with h.c.p. lattice. Although the method is less precise than neutron diffraction and X-ray methods, it is more rapid and cheap. Because of this the ultrasonic method is more effective for application in production conditions. Highly perspective application of the given method is, in particular, US NDT of the thin-walled tubes- shells of fuel element, the texture of which influences on the operation properties essentially.