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1

Quantitative X-Ray Diffraction Analysis of Zn-Al Based Alloys

Gogola P., Gabalcová Z., Suchánek H., Babinec M., Bonek M., Kusý M.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

959--966

EN

The paper describes modification to Fm3 ̅m (space group no. 225) lattice of aluminium based α-solid solution observed in Zn-Al alloys required to properly correlate quantitative data from X-ray diffraction analysis with results obtained from quantitative scanning electron microscopy image analysis and those predicted from Zn-Al binary phase diagram. Results suggests that 14 at.% of Zn as a solute atom should be introduced in crystal lattice of aluminium to obtain correct estimation of phase quantities determined by quantitative X-ray diffraction analysis. It was shown that this modification holds for Cu mould cast as well as annealed and water-cooled samples of Zn-3wt.%. Al and Zn-5wt.% Al.

2

The Influence of the Laser Beam Fluence on Change in Microstructure, Microhardness and Phase Composition of Feb-Fe2B Surface Layers Produced on Vanadis-6 Steel

Bartkowska A., Jurči P., Hudáková M., Bartkowski D., Kusý M., Przestacki D.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

791--800

EN

The paper presents the study results of laser modification of Vanadis-6 steel after diffusion boronized. The influence of laser beam fluence on selected properties was investigated. Diffusion boronizing lead to formation the FeB and Fe2B iron borides. After laser modification the layers were consisted of: remelted zone, heat affected zone and substrate. It was found that increase of laser beam fluence have influence on increase in dimensions of laser tracks. In the thicker remelting zone, the primary dendrites and boron eutectics were detected. In the thinner remelting zone the primary carbo-borides and eutectics were observed. In obtained layers the FeB, Fe2B, Fe3B0.7C0.3 and Cr2B phases were detected. Laser remelting process caused obtained the mild microhardness gradient from the surface to the substrate. In the remelted zone was in the range from 1800 HV0.1 to 1000 HV0.1. It was found that the laser beam fluence equal to 12.7 J/mm2 was most favorable. Using this value, microhardness was relatively high and homogeneous.

3

Evaluation of tribological properties of laser textured hardened tool steels

Šugárová J., Frnčík M., Necpal M., Moravčíková J., Kusý M.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2016

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z. 88 [293], nr 3

233--245

EN

In this paper the laser surface texturing (LST) technology as one of the methods of tribological properties modifying of mating steel surfaces is analysed. The area density of dimple-like depression along with the dimple diameter are the only main factors which significantly influence the friction coefficient value, therefore the effect of different values of area density of dimples: 6 %, 11 % and 16 % on the contact coefficient of friction was analysed. Surface textures were manufactured on the planar areas of compression platens (90MnCrV8 tool steel) using a pulsed-beam laser. The values of coefficients of friction were obtained via a ring compression test. Test sample compression was realized in lubrication-free and hydrodynamic regime. A significant improvement of tribological properties in contact steel areas was experimentally observed in both friction regimes. The results of experiments showed that by applying of surface texturing with defined shape and dimensions of dimples and lubricating oil at the same time, the coefficient of friction value can be reduced to about of 75%.

PL

W artykule przedstawiono analizę technologii laserowego teksturowania powierzchni (LTP) jako jedną z metod modyfikacji właściwości tribologicznych współpracujących powierzchni stalowych. Podstawowy szyk tekstury powierzchni składa się z wgłębień o zakrzywionym dnie, które są umieszczone w narożach sześciokąta foremnego. Dodatkowo jedno zagłębienie jest umieszczone w środku szyku. Parametry zagłębień są następujące: średnica 100±5 μm, głębokość 11 μm, stosunek głębokości do średnicy 0,11. Gęstość powierzchniowa wgłębień oraz średnica wgłębienia są głównymi czynnikami, które w sposób istotny wpływają na wyjściową wartość współczynnik tarcia, dlatego analizowano wpływ różnych wartości gęstości powierzchniowej wgłębień, tj. 6%, 11% i 16% na wartość kontaktowego współczynnika tarcia. Tekstury powierzchni zostały utworzone na płaskich powierzchniach płyt dociskowych (stal narzędziowa 90MnCrV8) za pomocą wiązki pulsacyjnej lasera. Wartości współczynników tarcia otrzymano za pomocą testu ściskania pierścienia. Próbki do badań ze stali węglowej S235JRG1 były ściskane osiowo pomiędzy parą teksturowanych płyt dociskowych. Ściskanie badanej próbki zostało zrealizowane w warunkach braku smarowania oraz smarowania hydrodynamicznego. Wyniki doświadczalne wykazały, że przez zastosowanie teksturowania powierzchni o określonym kształcie i wymiarach wgłębień oraz ciekłego smaru, wartość współczynnika tarcia może być zmniejszona prawie o 75%.

4

The corrosion performance of Zn-Al-Mg based alloys with tin addition in neutral salt spray environment

Gondek J., Babinec M., Kusý M.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 70, nr 2

70--77

EN

Purpose: Ternary Zn-Al-Mg system was modified with 0.5, 1.0, 2.0 and 3.0 wt. % of Sn in order to study its microstructure, phase composition and corrosion performance in neutral salt spray test. Addition of tin was devised to modify phase composition and phase quantities, particularly Zn2Mg intermetallic phase. Design/methodology/approach: Ternary and quaternary alloys were prepared from 4N purity elements under a flux layer. Chemical composition was verified using optical emission spectrometer. Light and scanning electron microscopy was used to study microstructure further complemented with local chemical analysis using energy dispersive X-ray spectrometry. Phase composition and phase quantity of as-cast samples and samples after corrosion tests were determined using X-ray diffraction. Performance of alloys in neutral salt spray test was evaluated by method of weight change. Findings: Addition of Sn caused change in solidification mechanism which influenced also phase composition and phase quantity. Typical weight loss was determined after exposure of ternary system in salt spray chamber. Contrary, weight gain was observed in all four tin alloyed ternary systems. This finding was explained by blister formation. Research limitations/implications:Results introduced in this paper are limited to relatively slowly cooled coarse-grained samples. Different cooling rates may affect phase composition and also corrosion performance. Practical implications: Paper shows alternative way of changing phase composition of ternary Zn-Al-Mg system by alloying using tin. Change in phase composition may have, however, impact on corrosion performance as it is shown in this paper. Originality/value: Paper describes change of the corrosion mechanism when ternary Zn-Al-Mg system is alloyed with Sn. It also shows that blister formation found in quaternary system depends on grain orientation with respect to the exposed surface.