СУЧАСНИЙ СТАН ТА ПЕРСПЕКТИВИ РОЗВИТКУ НАНОСТРУКТУРУВАННЯ ДЕФОРМОВАНИХ МЕТАЛІВ І СПЛАВІВ ТА НАПИЛЕНИХ ПОКРИТТІВ

Abstract

The information presented in the article is an overview of the possibility of improving the mechanical properties of metals, alloys and sprayed coatings in order to obtain a dispersed, in particular, nanoscale substructure, which allows obtaining a set of unique operational characteristics, which, in turn, will increase the resource of parts of machines and mechanisms that are used in mechanical engineering.Today, the most common methodof nanostructuring is intensive plastic deformation (by friction, by equal-channel angular pressing, etc.), however, these methods can only be used for the manufacture of parts with a small cross-section, so the creation of new methods of deformation-thermal treatment is an urgent task of modern materials science.The paper shows the possibility of applying pre-deformation and pre-recrystallization heat treatment for technically pure iron, carbon steels of 1020 (сталь 20), 1045 (сталь 45), 1070 (сталь 70),A284Gr.D (Ст3) and C80W (У8) brands, alloyed steels of 5140H (40Х) and AISI 420 (20Х13) brands, Sv-08G2S (Св-08Г2С) gas-thermal and electric arc coatings, as well as Ni80Cr20 nichrome alloy and CuA19Mn2 (2.0960) bronze (БрАМц9-2).The work compares methods of static deformation with methods of intensive plastic deformation and shows that pre-recrystallization heat treatment allows to significantly strengthen metals (more than 30%) in combination with sufficient plasticity (for A284Gr.D (Ст3) steel, the relative elongation is up to 7.5%, and the relative narrowing is up to 75 %).The work presents the results of the experimental investigation of the influence of deformation and thermal factors on the mechanical properties, in particular, hardness and strength, of metals, alloys and sprayed coatings. It is established that the strengthening effect occurs due to the refinement of substructural elements, such as the size of coherent scatteringregions, the disorientation angle of subgrains, and the number of substructural elements to a nanoscale state. Thus, with the help of additional deformation followed by pre-recrystallization and heat treatment of carbon and alloyed steels, it is possible to obtain subgrains with a size of less than 200 nm with a disorientation angle of up to 2 ° with a relative amount of nanoscale subgrains of up to 65%.The possibility of industrial application of the proposed technology is shown on the example of production of regulating springs of membrane valves of pipelines made of 1070 (сталь 70) steel, which allows to increase the hardness by 19%.