Study of the influence of the structural grain size on the mechanical properties of technical materials Untersuchung des Einflusses der Korngro ¨ ße auf die mechanischen Eigenschaften technischer Werkstoffe M. Harnic ˇa ´ rova ´ 1, 2 , J. Valı ´c ˇek 1, 2 , M. Kus ˇnerova ´ 1 , J. Kmec 1 , Z. Palkova ´ 1, 2 , I. Kopal 3 , J. Krmela 3 , A. Panda 4 The mechanical properties of technical materials depend on their structure. They are influenced not only by their chemical composition, but particularly by the structural grain size. Significant changes in the mechanical behaviour of materials are related both to surface and volume properties, and not only in the field of mechanical parame- ters. A wide range of physical and chemical parameters changes as well. Nano-materi- als are the materials, the structural grain size of which is in the dimensional area from 10 9 to 10 7 m. Nano-particles and nanostructures are thus so small that their behav- iour is affected by atomic forces, properties of chemical bonding, and quantum phe- nomena. The wave nature of the very small particles begins to manifest itself. The aim of the authors is to contribute by their paper to the solution of the problems in the field of material engineering. This means to investigate the specifics in the behaviour of technical materials depending on the change in the structural grain size towards the nano-areas, as well as the design and use of new techniques of mathematical and physical modelling including the operative measurement method. Keywords: Nanomaterials / grain size / mechanical parameters / mathematical and physical modelling Die mechanischen Eigenschaften technischer Werkstoffe ha ¨ ngen von ihrer Struktur ab. Sie werden nicht nur von ihrer chemischen Zusammensetzung, sondern insbe- sondere von der Korngro ¨ ße beeinflusst. Wesentliche A ¨ nderungen im mechani- schen Verhalten von Werkstoffe ha ¨ ngen sowohl mit den Oberfla ¨ chen- als auch den Volumeneigenschaften zusammen und dies nicht nur im Bereich der mechani- schen Parameter. Eine Vielzahl von physikalischen und chemischen Parametern a ¨ ndern sich ebenfalls. Nanowerkstoffe sind die Werkstoffe, deren Korngro ¨ße im Corresponding author: M. Harnic ˇa ´ rova ´ , Department of Mechanical Engineering, Faculty of Technology, Insti- tute of Technology and Business in C ˇ eske ´ Bude ˇ jovice, Okruz ˇnı ´ 10, 37001 C ˇ ESKE ´ BUDE ˇ JOVICE, CZECH REPUBLIC, E-Mail: harnicarova@mail.vstecb.cz 1 Department of Mechanical Engineering, Faculty of Technology, Institute of Technology and Business in C ˇ eske ´ Bude ˇ jovice, Okruz ˇnı ´ 10, 37001 C ˇ ESKE ´ BUDE ˇ JOVICE, CZECH REPUBLIC 2 Faculty of Engineering, Slovak University of Agricul- ture in Nitra, Tr. A. Hlinku 2, 94976 NITRA, SLOVAK REPUBLIC 3 Faculty of Industrial Technologies in Pu ´ chov, Alex- ander Dubc ˇek University of Trenc ˇı ´n, Ivana Krasku 491/30, 02001 PUCHOV, SLOVAK REPUBLIC 4 Technical University of Kosice, Faculty of Manufac- turing Technologies with a seat in Pres ˇov, Bayerova 1, 08001 PRES ˇ OV, SLOVAK REPUBLIC Materialwiss. Werkstofftech. 2019, 50, 635–645 DOI 10.1002/mawe.201800177 635 © 2019 WILEY-VCH Verlag GmbH & CO. KGaA, Weinheim www.wiley-vch.de/home/muw