The solid-state reaction in Pt(15 nm)/Fe(15 nm) and Pt(15 nm)/Ag(10 nm)/Fe(15 nm) thin films after postannealing at 593 K and 613 K for different annealing times has been studied. The structural properties of these samples were investigated by various methods including depth profiling with secondary neutral mass spectrometry, transmission electron microscopy, and X-ray diffraction. It is shown that after annealing at the above temperatures where the bulk diffusion processes are still frozen, homogeneous reaction layers of FePt and FePt with about 10 at.% Ag, respectively, have been formed. Corresponding depth profiles of the element concentrations revealed strong evidence that the formation mechanism is based on a grain boundary diffusion induced solid-state reaction in which the reaction interfaces sweep perpendicularly to the original grain boundary. Interestingly, X-ray diffraction indicated that in both thin-film systems after the solid-state reaction the ordered L1 0 FePt

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FePt thin films with a thickness of 30 nm were deposited by dc magnetron sputtering at room temperature onto SiO 2 (100 nm)/Si(100) substrates. These films were post-annealed in a temperature range of 500 C to 900 C for 30 s in three different atmospheres-N 2 , Ar, and forming gas (ArþH 2 (3 vol. %)). Irrespective of the annealing atmosphere, the chemically ordered L1 0 FePt phase has formed after annealing at 500 C. Higher annealing temperatures in N 2 or Ar atmosphere resulted in a strong increase in grain size and surface roughness but also in the appearance of a pronounced (001) texture in the FePt films. However, these films show the presence of iron oxide. In contrast, annealing in forming gas atmosphere suppressed the oxidation process and resulted in a reduced grain size and lower surface roughness. However, no (001)-but a strong (111)-texture was obtained after annealing at 700 C, which might be related to the reduced unit cell tetragonality and incorporation of hydrogen to the FePt lattice. Thus, this study clearly demonstrates that the oxygen/hydrogen content plays an important role in controlling the crystallographic orientation during post-annealing.

Оттиски доступны непосредственно от издателя Фотокопирование разрешено только в соответствии с лицензией 2016 ИМФ (Институт металлофизики им. Г. В. Курдюмова НАН Украины) Напечатано в Украине. 546 М. О. ВАСИЛЬЄВ, Б. М. МОРДЮК, С. І. СИДОРЕНКО та ін. зміцнення (200-350%) та зростання зносостійкости (в  7 разів) поверхні стопу Д16 спостерігаються за умов армування частинками Al 2 O 3 і B 4 C. Ключові слова: ультразвукове ударне оброблення (УЗУО), поверхневий нанокомпозит, інтенсивна пластична деформація, квазигідростатичне стиснення, зносостійкість. Исследовано влияние ультразвуковой ударной обработки (УЗУО) в инертной среде на структуру, фазовый состав и микромеханические свойства композиционных покрытий, сформированных внедрением в поверхностные слои алюминиевого сплава Д16 дисперсных частиц упрочняющих порошков Al 2 O 3 , B 4 C, BN и углеродных нанотрубок. Под действием интенсивной пластической деформации, вызванной УЗУО, происходят частичное дробление и внедрение частиц порошков и процесс наноструктуризации матричного сплава с формированием деформационных композитных слоёв. Максимальное упрочнение (200-350%) и увеличение износостойкости (в  7 раз) поверхности сплава Д16 происходит в условиях армирования частицами Al 2 O 3 и B 4 C. Ключевые слова: ультразвуковая ударная обработка (УЗУО), поверхностный нанокомпозит, интенсивная пластическая деформация, квазигидростатическое сжатие, износостойкость. The influence of ultrasonic impact treatment (UIT) in an inert atmosphere on the structure, phase composition and micromechanical properties of composite coatings formed by embedding of dispersed particles of Al 2 O 3 , B 4 C, BN hardening powders and carbon nanotubes into the surface layers of D16 aluminium alloy is investigated. Under influence of severe plastic deformation caused by UIT, a partial grinding and introduction of powder particles and the nanostructurization of matrix alloy with the deformation composite layers take place. The observed maximum strengthening (200-350%) and durability increase ( 7 times) of D16 alloy surface occur due to reinforcement by Al 2 O 3 and B 4 C particles.

Îòòèñêè äîñòóïíû íåïîñðåäñòâåííî îò èçäàòåëÿ Ôîòîêîïèðîâàíèå ðàçðåøåíî òîëüêî â ñîîòâåòñòâèè ñ ëèöåíçèåé 2017 ÈÌÔ (Èíñòèòóò ìåòàëëîôèçèêè èì. Ã. Â. Êóðäþìîâà ÍÀÍ Óêðàèíû) Íàïå÷àòàíî â Óêðàèíå. 50 М. О. ВАСИЛЬЄВ, Б. М. МОРДЮК, С. І. СИДОРЕНКО та ін. Обговорено можливий механізм формування залiзовмiсного поверхневого шару за інтенсивної пластичної деформації та масоперенесення Fe, спричинених багатократним ударним навантаженням при УЗУО бойком з армко-заліза. Ключові слова: ультразвукове ударне оброблення (УЗУО), поверхня, масоперенесення, механічне леґування, алюмінієві стопи, інертне середовище. The hardening process of the surface layers of 2024 aluminium alloy caused by structural evolution and mass transfer of Fe induced by ultrasonic impact treatment (UIT) with the pin from Armco-Fe carried out in both the air and an inert environment is studied. The cyclical nature of changes in microhardness, which comprises the alternating stages of hardening and plasticization, is confirmed. The increase in the microhardness of the surface layers of 2024 aluminium alloy of  30 m thick after the UIT process with the pin from Armco-Fe in an inert environment (4 GPa) and in the air (up to  9 GPa) is associated with the decrease in the size of coherent scattering areas during severe plastic deformation and with the increase in crystal lattice microstrains, with mechanochemical interaction between Al and Fe with the formation of Fe-Al intermetallic phases as well as between Cu and O during UIT in the air. A possible mechanism for the formation of the iron-containing surface layer by severe plastic deformation and mass transfer of iron caused by repetitive impact loading at UIT with the pin of Armco-Fe is discussed.