01697nas a2200205   4500008004100000245008800041210006900129300001400198490000800212520109100220653000801311653000701319100002401326700001901350700002301369700001801392700001901410700001601429856004601445       2022                        eng d00aExperimental analysis of microhardness changes of subsurface areas affected by WEDM0 aExperimental analysis of microhardness changes of subsurface are  a1979-19910 v2363 a<p>The influence of the surface area by the impact of high temperatures after wire electric discharge machining (WEDM) is a known fact. However, the affected parameters also include a change in microhardness. In order to further investigate this statement, 5 different ferrous and non-ferrous materials were selected, from which three samples were always made with different settings of machine parameters (gap voltage, pulse on and off time, wire feed and discharge current). This examined not only the effect of the machining itself on the material but also whether the change in the microhardness of the material is affected by the setting of the machine parameters. In order to measure the microhardness of the subsurface layer, a metallographic preparation was made from each sample, which enabled accurate measurements always in the same area. Subsequent evaluation revealed that the microhardness may not be affected at all and everything depends only on the type of material being machined. The changes in microhardness affected by setting machine parameters are negligible.</p>10aAIF10aMF1 aMouralova, Katerina1 aMichna, Stefan1 aZahradnicek, Radim1 aBednar, Josef1 aPlichta, Tomas1 aFries, Jiri  uhttps://doi.org/10.1177/0954408922107838302627nas a2200181   4500008004100000022001400041245005600055210005600111300001100167490000800178520211100186653000802297653000702305100001902312700002302331700001902354856007202373       2022                        eng d  a0040-609000aSurface topography affects the nanoindentation data0 aSurface topography affects the nanoindentation data  a1391050 v7453 a<p>The near-surface mechanical properties of thin films as well as bulk materials are amongst the key parameters important for their application, and instrumented nanoindentation is a standard technique for determining these mechanical properties. However, it is known that the surface topography of the characterized materials may affect the nanoindentation data when a sharp indenter for small penetration depths (displacements) is used. A thin film of hydrogenated amorphous silicon carbide with a thickness of 1.0&nbsp;μm was deposited on a silicon wafer by plasma-enhanced chemical vapour deposition. The cyclic nanoindentation was used to construct a depth profile of mechanical properties for the flat surface (0.5&nbsp;nm roughness) of the thin film, which made it possible to determine its modulus of elasticity of 83&nbsp;GPa and hardness of 8.6&nbsp;GPa unaffected by the silicon substrate. Grains with a spherical cap geometry with a typical radius of 0.5&nbsp;µm and a&nbsp;height of 60&nbsp;nm are distributed along the flat surface of the film. The grains have the same mechanical properties as the deposited film. Depth profiles of mechanical properties were determined for different types of contact between the Berkovich indenter with a radius of 50&nbsp;nm and the selected grain (grain top, grain foot, two or three grains); i.e. for these measurements the following applied - the radius of the tip curvature was less than grain radii (RBerkovich &lt; Rgrain). Residual imprints after nanoindentation measurements were carefully observed by atomic force microscopy and scanning electron microscopy. The near-surface mechanical properties were significantly affected by the surface topography, and the determined modulus of elasticity and hardness were crucially under- or overestimated in the range of 50% to 100% compared to the real values. The nature of these deviations was discussed. The solution is to use cyclic nanoindentation performed on the flat surfaces or on the top of grains, followed by extrapolation of the depth profiles to the zero-contact depth (film surface).</p>10aAIF10aMF1 aPlichta, Tomas1 aZahradnicek, Radim1 aCech, Vladimir  uhttps://www.sciencedirect.com/science/article/pii/S0040609022000268