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Документ Erosion features of tungsten surfaces under combined steady-state and transient plasma loads(Національний науковий центр "Харківський фізико-технічний інститут", 2016) Herashchenko, S. S.; Makhlaj, V. A.; Girka, O. I.; Aksenov, N. N.; Bizyukov, I. A.; Malykhin, S. V.; Surovitskiy, S. V.; Sereda, K. N.; Bizyukov, A. A.The paper presents the experimental research on damage of the tungsten surfaces under combined plasma exposures. Steady-state hydrogen exposures (particle flux of 2×10²² mˉ² sˉ¹, heat flux of 1.7 MW/m², fluence of 10²⁶ mˉ², average ion energy of 2 keV) were provided by FALCON ion source. The pulsed plasma loads below the tungsten melting threshold (hydrogen plasma streams with surface heat load of 0.45 MJ/m² and the pulse duration of 0.25 ms) were performed by means of QSPA Kh-50 device. The behavior of structure, sub- structure and stress-state of tungsten samples have been studied after each cycle of pulsed and steady-state plasma loads.Документ Structural-phase changes in thin films and surface layers of Ti₄₁.₅Zr₄₁.₅Ni₁₇ alloy, stimulated by radiation-thermal impact of hydrogen plasma(Національний науковий центр "Харківський фізико-технічний інститут", 2018) Surovitskiy, S. V.; Herashchenko, S. S.; Makhlaj, V. A.; Malykhin, S. V.; Kopylets, I. A.Документ Materials surface damage and modification under high power plasma exposures(2018) Garkusha, I. E.; Makhlaj, V. A.; Byrka, O. V.; Taran, V. S.; Voitsenya, V.; Malykhin, S. V.; Herashchenko, S. S.; Surovitskiy, S. V.; Nowakowska-Langier, K.; Sadowski, M. J.; Skladnik-Sadowska, E.; Terentyev, D.Influence of powerful plasma impacts on several materials used for the construction of energy systems, i.e. different grades of steels as well as tungsten coatings, has been discussed. Irradiations of these materials with hydrogen and helium plasma streams have been performed in several high-current-pulse and quasi-stationary plasma accelerators which provided the variation of a power load upon the exposed surface as well as changes of the particle flux in wide ranges: the energy flux density in the range of 1-25 MJ/m2, particle flux - up to 1026-1029 ion/m2s, the plasma stream velocity - up to about 500 km/s, and the pulse duration in the range of 1-250 μs. A response of the investigated materials to extreme plasma loads, which are relevant to transient events in fusion reactors, is briefly discussed. It is demonstrated that a broad combination of mechanisms of powerful plasma interactions with various materials includes not only a surface damage caused by different erosion mechanisms, but under certain conditions it may also result in a significant improvement of material properties in the nearsurface surface layer of several tens μm in thickness. Some improvement of the structure and substructure of such a layer may be caused by the high-speed quenching, the shock wave formation and material alloying with plasma- and coating-species. The creation of unique surface structures and a considerable improvement of physical and mechanical properties of different materials can be achieved by the pulsed plasma alloying, i.e. pre-deposited coating modifications and mixing caused by the impacting plasma streams.Документ Erosion features of tungsten surfaces under combined steady-state and transient plasma loads(Національний науковий центр "Харківський фізико-технічний інститут", 2016) Herashchenko, S. S.; Aksenov, N. N.; Bizyukov, I.; Girka, O.; Makhlaj, V. A.; Malykhin, S. V.; Surovitskiy, S. V.; Bizyukov, A.; Garkusha, I. E.Документ Structure evolution of tungsten coatings exposed to plasma flow under ITER ELM relevant conditions(Національний науковий центр "Харківський фізико-технічний інститут", 2016) Malykhin, S. V.; Surovitskiy, S. V.; Makhlaj, V. A.; Aksenov, N. N.; Byrka, O. V.; Borisova, S. S.; Herashchenko, S. S.; Reshetnyak, M. V.; Garkusha, I. E.Документ Alloying and modification of stainless steels by powerful plasma streams(Національний науковий центр "Харківський фізико-технічний інститут", 2016) Makhlaj, V. A.; Aksenov, N. N.; Byrka, O. V.; Chunadra, A. G.; Herashchenko, S. S.; Malykhin, S. V.; Mikhailov, I. F.; Sereda, K. N.; Surovitskiy, S. V.; Garkusha, I. E.Документ Alloying and modification of stainless steels by powerful plasma streams(2016) Makhlaj, V. A.; Aksenov, N. N.; Byrka, O. V.; Chunadra, A. G.; Herashchenko, S. S.; Malykhin, S. V.; Mikhailov, I. F.; Sereda, K. N.; Surovitskiy, S. V.The stainless steel surfaces coated of tungsten have been alloyed and modified with powerful QSPA Kh-50 plasma streams. The plasma streams exposures result in modification of steel-based materials and formation of re-solidified layers. The changes of substrate texture were also registered. Phase characterized by body-centered cubic lattice appeared due to recrystallization of affected material. Thus, the favorable conditions were created for penetration of tungsten into the stainless steel bulk. Growth of lattice parameter was observed as result of plasma irradiation of coated samples. It's indication of tungsten penetration into the depth of substrates.Документ Structure evolution of tungsten coatings exposed to plasma flows under ITER ELM relevant conditions(Kharkiv Institute of Physics and Technology, 2017) Malykhin, S. V.; Surovitskiy, S. V.; Makhlaj, V. A.; Aksenov, N. N.; Byrka, O. V.; Borisova, S. S.; Herashchenko, S. S.; Reshetnyak, V. V.Structure, substructure and stress parameters both on the surface and distributed by depth in the tungsten/steel coatings exposed to high energy hydrogen plasma fluxes were studied by X-ray diffraction methods. The hydrogen plasma exposure results in the following recrystallization processes in the thin surface layer of the coating: appearing the texture axis normal to the surface; increasing the coherence length from 60 nm in the initial state to 80 nm after the plasma exposure; completely annealed micro-strains; and dislocation density lowered twice in the exposed surface layer all these facts confirm the thermal character of the hydrogen plasma influence.