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Open access

P. Mrva, D. Kottfer and Ł. Kaczmarek

Effect of Shot Peening and NiAl Coating on Fatigue Limit of Mg-Al-Zn-Mn Alloy

The paper deals with an influence of cylic load on fatigue limit of the Mg-Al-Zn-Mn alloy without or with the NiAl coating. The fatigue limit was determined for the following three types of specimens of the Mg-Al-Zn-Mn alloy: (1) fine-turned specimens; (2) fine-turned specimens with an application of the shot peening process; (3) fine-turned and shot-peened specimens with the NiAl coating deposited by the thermal spraying technique. A standard measurement of the fatigue limit was used for the analytical determination of the Wohler curves (S-N curves). The Wohler curves for the specimens (1) and (3) were in agreement with those presented in literature. The specimens (2) exhibited a lower value of the fatigue limit compared with that of the specimens (1), although the increase of the fatigue limit of the specimens (2) was expected due to the presence of the application of the shot peening process. An analysis of reasons of the decrease of the fatigue limit of the specimens (2) is presented.

Open access

Łukasz D. Kaczmarek, Piotr Haładziński, Lech Kaczmarek, Błażej Bączkowski, Michał Ziarko and Stephan U. Dombrowski

A comprehensive understanding of participants’ motives to complete web-based surveys has the potential to improve data quality. In this study we tested the construct validity of a scale developed to measure motivation to participate in webbased surveys. We expected that 7 different motivations observed in our previous study will form a 3-factor structure, as predicted by Self-Determination Theory. This web-based questionnaire study comprised 257 participants completing the Voluntary Participation in Online Studies Scale. Their responses to 21 items underwent a principal component analysis and confi rmatory factor analysis. As we expected, three factors were identifi ed: intrinsic motivation, extrinsic motivation and amotivation. In line with Self-Determination Theory there are three distinct groups of motives among web-surveys participants with amotivation as an understudied motivational state. We discuss the results suggesting which types of motivation might lead to higher quality of data with an emphasis on possible negative effects of amotivation.

Open access

D. Kottfer, M. Ferdinandy, L. Kaczmarek, P. Trebuňa and P. Hvizdoš

This study investigates the selected properties of the thin Ti coating applied by activated evaporation EB PVD technique. This technique was used for the deposition of Ti thin coating onto inner surface of OKhN3 MFA steel tubes. Deposition process was carried out at temperature 200°C. Conventional type of coatings - monolayer Ti - was analyzed by standard techniques for surface status and quality assessment - coating thickness, chemical composition by EDX analysis, adhesion, hardness, roughness, and growth direction of columns at room temperature. Ti monolayer achieved roughness Ra equal from 0.42 μm to 0.47 μm. The resulting hardness was from 2 GPa to 8.5 GPa depending on the sample location inside the vacuum chamber. Placing of the coated surface also affected the direction of grain growth of Ti coating columns. The angles α of grain growth were found to be from 40° to 60°. Angle α increased two to three times more than the incidence angle β (from 12° to 28°) of evaporated Ti particles. Values of the adhesion measured along the Ti growth direction were mostly higher (up to 10%) or the same as those measured perpendicular to it.

Open access

Łukasz D. Kaczmarek, Błażej Bączkowski, Jolanta Enko, Barbara Baran and Peter Theuns

Abstract

Curiosity is a personality trait that is inversely related to depression and positively related to subjective wellbeing. However, the relationship between curiosity and these two outcomes is still unclear which hampers our general understanding of well-being. Based on research within positive psychology that showed character strengths such as curiosity can indirectly decrease depression, we hypothesized that the inverse relationship between curiosity and depression would be mediated by subjective well-being. Two hundred and fifty seven participants, between 18 and 64 years old (M = 24.50, SD = 8.33) completed a web-based survey comprising: The Curiosity and Exploration Inventory - II, Center for Epidemiological Studies - Depression and the Steen Happiness Index. We found that well-being mediated the relationship between curiosity and depression. The results indicate that curious individuals tend to report higher levels of subjective well-being which, in turn, is associated with lower levels of depression. Our findings contribute to the understanding of positive results obtained from clinical samples that underwent positive psychotherapy of depression.

Open access

Ł. Kaczmarek, M. Steglinski, J. Sawicki, J. Swiniarski, D. Batory, K. Kyzioł, Ł. Kołodziejczyk, W. Szymanski, P. Zawadzki and D. Kottfer

This paper describes two stages of optimization of the properties of 2024 and 7075 aluminium alloys, in particular their resistance to pitting by first T6, T6I6 or T6I4 treatment, and second increase its tribological properties by depositing by RF PACVD method a gradient coating of high adhesion to the substrate.

Quantitative microstructural characteristics reveals that it is possible to increase hardness (up to 190HV for 7075 alloy) with relatively high yield strength (520 MPa) and high ultimate elongation (about 20%) by optimizing dispersion of precipitates using two-stage artificial aging process.

Next to eliminate forming of thin Al2O3 layer with relatively poor adhesion to the aluminium substrate, gradient a-C: H/Ti layers synthesis hybrid plasma chemical RF PACVD reactor equipped with pulsed magnetron sputtering system was used. Using such configuration enables forming a thick and highly adherent diamond-like carbon layer on aluminium surface with low coefficient of friction (0.05), at a substrate temperature below 470K. Due to application of Ti magnetron cathode it was possible to improve the adhesion strength up to 30mN of diamond-like carbon layer to the covered substrate. Influence of deposition parameters on microhardness profile as well as adhesion and morphology were determined by nanotest and AFM, respectively.

Open access

J. Domaradzki, D. Kaczmarek, M. Mazur, D. Wojcieszak, J. Halarewicz, S. Glodek and P. Domanowski

Abstract

The paper presents results of optical and surface morphology investigations of semitransparent silver single thin films deposited on glass substrate in relation to their heat radiation treatment. The thickness of 15 nm for the silver thin films was selected using computer designing of optical spectra and the films were deposited using electron beam evaporation process. Optical transmission and reflection were investigated for as deposited samples and after exposition to heat radiation from quartz-halogen lamp. The changes in the optical spectra were observed which suggested degradation of deposited heat mirrors. Structure and surface morphology studies performed using scanning electron microscopy, X-ray photoelectron spectroscopy and atomic force microscopy allowed us to conclude about formation of nanometric silver islands, regularly distributed over the surface of the glass substrate after exposure to heat treatment.

Open access

M. Mazur, K. Sieradzka, D. Kaczmarek, J. Domaradzki, D. Wojcieszak and P. Domanowski

Abstract

In this paper investigations of structural and optical properties of nanocrystalline Ti-V oxide thin films are described. The films were deposited onto Corning 7059 glass using a modified reactive magnetron sputtering method. Structural investigations of prepared Ti-V oxides with vanadium addition of 19 at. % revealed amorphous structure, while incorporation of 21 and 23 at. % of vanadium resulted in V2O5 formation with crystallites sizes of 12.7 and 32.4 nm, respectively. All prepared thin films belong to transparent oxide semiconductors due to their high transmission level of ca. 60–75 % in the visible light range, and resistivity in the range of 3.3·102–1.4·105 Ωcm. Additionally, wettability and hardness tests were performed in order to evaluate the usefulness of the films for functional coatings.

Open access

Ł. Kaczmarek, P. Zawadzki, M. Stegliński, R. Wójcik, M. Klich, K. Kyzioł, D. Kottfer, B. Januszewicz and W. Pawłowski

Abstract

The article present the results of the study on the improvement of mechanical properties of the surface layer of 7075 aluminum alloy via two-stage aging combined with shot peening. The experiments proved that thermo-mechanical treatment may significantly improve hardness and stress distribution in the surface layer. Compressive stresses of 226 MPa±5.5 MPa and hardness of 210±2 HV were obtained for selected samples.

Open access

Sebastian Borucki, Jacek Łuczak, Dariusz Zmarzły, Andrzej Cichoń, Jerzy Filipiak, Tadeusz Gudra, Dariusz Banasiak, Krzysztof Herman, Krzysztof Opieliński, Tomasz Hejczyk, Krzysztof Jasek, Mateusz Pasternak, Michał Grabka, Witold Kardyś, Andrzej Milewski, Adam Kawalec, Michał Kunicki, Marta Okoń-Fąfara, Bartłomiej Fąfara, Aneta Olszewska, Piotr Pruchnicki, Marcin Wrzosek, Józef Nicpoń, Przemysław Podgórski, Tadeusz Pustelny, Tomasz Rogala, Piotr Serafin, Marta Okon-Fafara, Marcin Szugajew, Czeslaw Lesnik, Adam Kawalec, Olga Stec, Tomasz Rogala, Adam Kawalec, Grzegorz Szerszeń, Franciszek Witos, Daria Wotzka, Agnieszka Boruń, Adam Bald, Marzena Dzida, Sylwia Jężak, Monika Geppert-Rybczyńska, Katarzyna Kaczmarek, Tomasz Hornowski, Arkadiusz Józefczak, Arkadiusz Józefczak, Tomasz Hornowski, M. Kubovčíková, A. Skumiel, Z. Rozynek, M. Timko, Krzysztof Klimaszewski, Peter Kopcansky, Bogumił Linde, Milan Timko, Vyacheslav N. Verveyko, Marina V. Verveyko, Darya V. Verveyko, Andrey Yu. Verisokin, Nikita S. Chebrov, Witold Mikulski, Dariusz Pleban, Danuta Augustyńska and Bożena Smagowska