Obrabotka Metallov 2018 Vol. 20 No. 4

OBRABOTKAMETALLOV Vol. 20 No. 4 2018 104 MATERIAL SCIENCE The Effect of Equal-Channel Angular Pressing on the Surface Quality of Aluminum Alloy 7075 after Milling Andrey Filippov 1 , 2, a,* , Sergei Tarasov 1, 2, b , Oleg Podgornykh 1, c , Nikolay Shamarin 1, d , Andrey Vorontsov 2, e 1 National Research Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk, 634050, Russian Federation 2 Institute of Strength Physics and Materials Science of the Siberian Branch of the RAS, 2/4, pr. Akademicheskii, Tomsk, 634055, Russian Federation a http://orcid.org/0000-0003-0487-8382, avf@ispms.ru, b http://orcid.org/0000-0003-0702-7639, tsy@ispms.ru , c https://orcid.org/0000-0002-7758-9242, podgornysh.o.a@mail.ru , d https://orcid.org/0000-0002-4649-6465, serper89@gmail.com , e Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2018 vol. 20 no. 4 pp. 96–106 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2018-20.4-96-106 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ARTICLE INFO Article history : Received: 16 October 2018 Revised: 31 October 2018 Accepted: 08 November 2018 Available online: 15 December 2018 Keywords : Aluminum alloy ECAP Milling Surface microgeometry Funding This work is supported by the Russian Science Foundation under grant No. 17-79-10013. Metallographic studies were carried out within the framework of the Program of Basic Scientific Research of the State Academies of Sciences for 2013–2020, line III.23. ABSTRACT Introduction. The development of instrument and mechanical engineering is based on the achievement of high quality indicators and precision dimensional processing of modern structural materials. An important direction of improving the manufacturing technology of critical products is the use of materials with improved physical and mechanical properties and structure. Most often used methods of severe plastic deformation (SPD) are used to obtain such materials. As a result of SPD exposure, an ultrafine-grained (UFG) material structure is formed and its strength increases. The preservation of structural integrity and mechanical properties is an important task in the manufacture of parts from UFG materials that have a low temperature of the onset of recrystallization processes. During dimensional processing, the material is subject to significant deformation and thermal effects, which can affect its structural integrity and mechanical properties. Milling is one of the most common methods for producing high-quality parts from aluminum alloys. This method is preferred for dimensional processing of aluminum alloys with a UFG structure, since it is characterized by a local effect on thin surface layers of the material, in which no substantial heating of the entire volume of the workpiece occurs. The deformation of the surface layer of the material under the action of the cutting blade of the cutter forms the micro-relief of the surface of the part. The difference in the deformation behavior of coarse-grained (CG) and UFG materials can significantly affect the quality of mechanical processing of the latter. As a result, the known optimal machining conditions may not be applicable to UMP materials. The purpose of the work : to study the effect of structural changes in aluminum alloy 7075 on the quality of its machining during milling. In this work, samples of aluminum alloy 7075 in the as-delivered condition and after structure formation are investigated using modern metal-cutting tools and equipment, as well as recommended cutting conditions. The methods of investigation are mechanical tests for compression and tension, optical metallography, transmission electron microscopy, laser scanning microscopy. Results and discussion. Based on the obtained experimental results, it can be concluded that ECAP is an effective way to improve the quality of surface machining when milling 7075 aluminum alloy. At the same time, to ensure the optimum ratio of processing quality and high mechanical strength, two ECAP passages are sufficient, under the selected conditions for the process of structure formation. The obtained results indicate a great potential for the use of products from bulk UFG materials in industry due to the possibility of combining high mechanical properties and quality of dimensional machining in them. The data obtained can be applied in the design of technological processes for the machining of aluminum alloy 7075 with an ultrafine-grained structure under conditions of mass production engineering. ______ * Corresponding author Filippov Andrey V. , Ph.D. (Engineering), Assistant Professor Institute of Strength Physics and Materials Science of the Siberian Branch of the RAS 2/4, pr. Akademicheskii Tomsk, 634055, Russian Federation Tel.: 8 (913) 128-72-07, e-mail: avf@ispms.ru For citation: Filippov A.V., Tarasov S.Yu., Podgornykh O.A., Shamarin N.N., Vorontsov A.V. The effect of equal-channel angular pressing on the surface quality of aluminum alloy 7075 after milling. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2018, vol. 20, no. 4, pp. 96–106. doi: 10.17212/1994-6309-2018-20.4-96-106. (In Russian). https://orcid.org/0000-0002-4 334 - 7616 , vav@ispms.com