Formation of Polygonization Nanoscale Substructure and Its Impact on the Physical and Mechanical Properties of Metals, Alloys, and Sprayed Coatings
O. M. Dubovyy, A. A. Karpechenko, M. M. Bobrov, O. O. Zhdanov, T. O. Makrukha, Yu. E. Nedelko
Admiral Makarov National University of Shipbuilding, 9 Heroyiv Stalingradu Ave., UA-54025 Mykolaiv, Ukraine
Received: 19.08.2016. Download: PDF
The review of scientific papers devoted to nanostructurization of products by methods of the intensive plastic deformation (IPD) is presented. The analysis of application of methods of mechanothermal and thermomechanical formation of the polygonization substructure in metals is carried out. The perspectives and drawbacks of the state-of-the-art formation of shredded and nanoscale substructures are shown. The possibilities of such formation of substructure, which are not used fully because of processes of dynamical and collecting polygonization taking place at comparatively long holding time and high temperature are proven. Nanostructurization of large parts by the IPD methods causes significant technical and technological difficulties and are not economically efficient. The main part of these methods is not proven to practical application. The results of previous research, which provide outlook for next research and application of method of the shredded polygonization substructure formation by pre-recrystallization heat treatment of metals, alloys, and sprayed coatings, are presented. The investigations are carried out on technically clean metals (Fe, Ni, Cu, Al, Ag) and allow finding out the influence of temperature, holding time, degree of previous plastic deformation, and crystal-lattice type on processes of strengthening by pre-recrystallization heat treatment. The studies are executed on carbonaceous (20, 40, 45, U8) and alloyed (40H, 12H13, 20H13, 40H13, 18H2N4MA, 12H18N10T, PH18N15, PRH18N9, EP533-ID, Sv-08G2S) steels and alloys (Ni80Cr20, BrAMts 9-2, D16) to identify patterns of the influence of amount of carbon and alloying elements on the processes of strengthening by pre-recrystallization heat treatment. The influence of the IPD methods on both the size of coherent X-ray scattering regions and the hardness is investigated by example of comprehensive pressing and traditional compression deformation with next pre-recrystallization heat treatment, which provides maximum hardness of the material. As demonstrated by X-ray diffraction and electron microscopy, the pre-recrystallization heat treatment of plastically deformed metals and steels by means of the modes, which provide the highest characteristics of physical and mechanical properties, causes shredding of substructure and allows to form nanoscale elements in the structure of metals and steels deformed by compression more than 60%, whose number can reach 25% of the total number of the structural components. The increasing of stability of shredded polygonization substructure at increasing in temperature and holding time by blocking subgrains’ growth thought processes of artificial ageing or stable dislocation tangles’ formation is shown and enables to expand the industrial applications of pre-recrystallization heat treatment of metals, alloys, and sprayed coatings.
Key words: pre-recrystallization heat treatment, nanoscale substructure, physical and mechanical properties of metals, alloys, and sprayed coatings.
PACS: 81.05.Bx, 81.07.Bc, 81.10.Jt, 81.15.Rs, 81.20.Hy, 81.40.Ef, 83.50.Uv
Citation: O. M. Dubovyy, A. A. Karpechenko, M. M. Bobrov, O. O. Zhdanov, T. O. Makrukha, and Yu. E. Nedelko, Formation of Polygonization Nanoscale Substructure and Its Impact on the Physical and Mechanical Properties of Metals, Alloys, and Sprayed Coatings, Metallofiz. Noveishie Tekhnol., 39, No. 2: 209—243 (2017) (in Ukrainian)