Obrabotka Metallov 2019 Vol. 21 No. 1

OBRABOTKAMETALLOV Vol. 21 No. 1 2019 105 MATERIAL SCIENCE Investigation of Structural Factors that Increase the Mechanical Properties of Surface Layers Modified by Pulsed Electro-Beam Irradiation 1 Institute of Strength Physics and Materials Science SB RAS, 2/4, pr. Akademicheskii, Tomsk, 634055, Russian Federation 2 National Research Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk, 634050, Russian Federation 3 National Research Tomsk State University, 36 Lenin Avenue, Tomsk, 634050, Russian Federation a https://orcid.org/0000-0001-9396-0219, igkon@ispms.tsc.ru, b http://orcid.org/0000-0002-8381-061X , shilko@ispms.ru , c http://orcid.org/0000-0003-1776-1212, ove45@mail.ru , d http://orcid.org/0000-0002-3447-0487, sp@ispms.tsc.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2019 vol. 21 no. 1 pp. 93–107 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2019-21.1-93-107 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov References 1. Mortensen A., Llorca J. Metal matrix composites. Annual Review of Materials Research , 2010, vol. 40, pp. 243–270. – doi: 10.1146/annurev-matsci-070909-104511. 2. Suryanarayana C., Al-Aqeeli N. Mechanically alloyed nanocomposites. Progress in Materials Science , 2013, vol. 58, pp. 383–502. doi: 10.1016/j.pmatsci.2012.10.001. ARTICLE INFO Article history : Received: 09 November 2018 Revised: 24 January 2019 Accepted: 29 January 2019 Available online: 15 March 2019 Keywords : Pulsed electron-beam irradiation Nanostructured layers Increased mechanical properties TiC-NiCr Numerical simulation Movable cellular automata method Funding The investigation is carried out with funding from the Basic Research Program of Russian Academy of Sciences for 2013–2020 (priority direction III.23). ABSTRACT Introduction Currently, a significant part of the cutting elements of the processing equipment is made of composite materials based on a metal matrix with dispersed ceramic inclusions. As a rule, such compositions are synthesized by powder metallurgy methods from a mixture of powders with a characteristic particle size from a few micrometers to tens of micrometers. Durability of cutting element is determined by the mechanical properties (including strength, hardness and fracture toughness) of thin surface layers of the composite. It is known that mechanical properties of the surface layers of the composites with microscale reinforcing ceramic inclusions are significantly inferior to the properties of these same compositions with characteristic sizes of reinforcing ceramic particles of tens to hundreds of nanometers. One of the successful ways to solve this problem is to modify the structure of the surface layers of synthesized composite with microscopic ceramic inclusions by the method of high-energy pulsed electron-beam irradiation in inert gas plasma. In the previous papers, the authors have shown that such processing leads to qualitative change in the structure of the surface layers, namely, to multiple crushing of original stochastically packed ceramic inclusions, their dissolution and subsequent precipitation in the form of regularly packed columnar particles with the preferential orientation normal to the surface. The change in the parameters of the internal structure determines a significant change in the mechanical properties of the surface layers and requires detailed parametric study. The aim of the work was to numerically study the influence of the key structural parameters, namely, the type of packing, the size and non-equiaxiality of ceramic particles on strength and fracture toughness of the modified surface layers . Results and discussion. The performed numerical analysis has revealed the key factors that determine the increase in the mechanical and tribological properties of modified surface layers of metal-ceramic composites. These are the features of packing and geometrical characteristics of ceramic inclusions. We showed that multiple decrease in the size of inclusions together with a change in their shape from equiaxial to substantially non-equiaxial and regular packing of inclusions with a preferential orientation normal to the surface lead to change in the pattern of stress distribution under compression from dispersed to frame-like as well as to elongation and complication of crack paths. This results in increase in the values of strength, yield stress and strain hardening of the surface layers. We explained that by varying the degree of non-equiaxiality of ceramic inclusions it is possible to achieve a necessary balance of competing mechanical characteristics like strength and fracture toughness. For citation: Konovalenko I.S., Shilko E.V., Ovcharenko V.E., Psakhie S.G. Investigation of structural factors that increase the mechanical properties of surface layers modified by pulsed electro-beam irradiation. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2019, vol. 21, no. 1, pp. 93–107. doi:10.17212/1994-6309-2019-21.1-93-107. (In Russian). ______ * Corresponding author Konovalenko Igor S. , Ph.D. (Physics and Mathematics), Senior Researcher Institute of Strength Physics and Materials Science SB RAS 2/4, pr. Akademicheskii, 634055, Tomsk, Russian Federation Tel.: 8 (3822) 286-975, e-mail: igkon@ispms.tsc.ru Igor Konovalenko 1, 2 , a,* , Evgenii Shilko 1, 3 , b , Vladimir Ovcharenko 1 , c , Sergei Psakhie 1 , d