Wyniki wyszukiwania - BazTech

1

Mikrostruktura odlewniczych stopów magnezu wzmacnianych cząstkami AL2O3

Piórkowski P., Kurzawa A.

Technical Issues

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2016

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nr 3

99--105

EN

The article discusses problems of performing magnesium alloys composites, reinforced with Al2O3 particles. The chemical composition of casting magnesium alloys, most common alloy elements and their impact on alloy properties were described. The method of producing magnesium composites - „stir casting” and the impact of Al2O3 particles on properties of a composite were also described. Research were performed based on the AZ91D alloy for several different mixing times. The microstructure of an alloy and composite materials, including phases identification and quality of matrix-particle interphase were analysed. Based on the microstructure, the mixing efficiency was set. The percentage of Al2O3 particles in a composite was defined. The results of hardness and impact of mixing time on a microstructure and properties of a Mg-Al2O3 composite were shown.

2

Utlenianie plazmowe stopu magnezu AZ91D prądem impulsowym

Nawrat G., Wierzbińska M., Gilewska M., Wieczorek T., Nieużyła Ł., Maciej A., Krząkała A., Gnot W.

Ochrona przed Korozją

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2013

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nr 11

483--489

PL

W pracy przedstawiono wyniki badań nad wytwarzaniem powłok konwersyjnych na stopie magnezu AZ91D przy zastosowaniu metody elektrolitycznego utleniania plazmowego (PEO) w alkalicznym roztworze krzemianu sodu z zastosowaniem prądu impulsowego. Przeprowadzone badania dotyczą wpływu dodatku czteroboranu sodu do kąpieli i częstotliwości prądu impulsowego na morfologię i chropowatość powierzchni, skład chemiczny i grubość powłok oraz na odporność korozyjną próbek stopu magnezu z nałożoną powłoką tlenkową określaną metodami elektrochemicznymi, w teście zanurzeniowym i w komorze solnej w środowisku chlorku sodu.

EN

In this work the results of investigations on conversion coating obtaining on AZ91D magnesium alloy by impulse current electrochemical plasma oxidation (PEO) in sodium silicate solution are presented. The influence of addition of sodium tetraborate to the bath and frequency of impulse current on morphology, roughness chemical composition and thickness of obtained layers was determined as well as on the corrosion resistance samples with oxide layer determined by electrochemical method, immersion test and salt spray chamber test in the environment of sodium chloride fog.

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Precipitation evolution and surface modification of magnesium alloys

Tański T., Król M., Dobrzański L.A., Malara S., Domagała-Dubiel J.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

87--149

EN

Purpose: The purpose of this publication is to present the results of own long-term research summarising the experience concerning as casting magnesium alloys, and in especially a thermal analysis describing the process of alloys crystallisation, standard heat treatment according to the occurring phase transitions and precipitation processes, surface treatment with the CVD and PVD methods, laser surface treatment of surface layers, as well as using the methods of Computer Materials Science. Design/methodology/approach: The research concerned in the first place an analysis of Mg-Al-Zn alloys crystallisation kinetics. Optimisation investigations for heat treatment conditions taking into consideration different cooling mediums were performed in order to identify fully the structure of the investigated magnesium casting alloys. Investigations were carried out of the structure and properties of coatings produced with the CVD and PVD methods on the investigated Mg-Al-Zn alloys. The last stage of investigating the presented Mg-Al-Zn alloys applied to laser surface treatment enabling to produce a quasi-composite structure of MMCs characterised by the gradient of phase composition as well as functional properties by feeding hard ceramic particles, in particular carbides and oxides, into the surface of the materials produced. Findings: Valuable and original results were achieved based on the broad scope of the research performed both, in cognitive and applicational terms, concentrated mainly on the analysis and influence of chemical composition and technological heat and surface treatment processes on the structure and properties of the investigated alloys. Practical implications: The properties of the core and surface layer of the part produced can be customised most advantageously by selecting the part’s material and its structure and properties formation processes appropriately along with the surface layer type and technology ensuring the required functional properties. Originality/value: The knowledge gathered for years concerning light metal alloys, and in particular Mg-Al-Zn alloys, of an undoubtedly valuable cognitive character, is dedicated not only to students but also postgraduates and researches to improve the conditions of education.

4

Kształtowanie struktury l własności warstwy wierzchniej odlewniczych stopów magnezu obróbką laserową

Dobrzański L. A., Domagała-Dubiel J.

Rudy i Metale Nieżelazne

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2011

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R. 56, nr 7-8

411-419

PL

W artykule zaprezentowano wyniki badań struktury, własności mechanicznych i odporności korozyjnej warstwy wierzchniej odlewniczych stopów magnezu Mg-AI-Zn o zróżnicowanym stężeniu aluminium MCMgAIBZnl, MCMgAI6Znl, MCMgAI9Znl oraz MCMgAll2Znl po laserowej obróbce powierzchniowej. Wtapianie laserowe cząstek WCw odlewnicze stopy magnezu wykonano przy użyciu lasem diodowego dużej mocy (HPDL). Stwierdzono, że struktura warstwy wierzchniej badanych odlewniczych stopów magnezu, krzepnąca po obróbce laserowej, charakteryzuje się zróżnicowaną morfologią i składa się z osnowy z dendrytami z eutektyką płytkową Mgl7All2 i Mg w obszarach międzydendrytycznych oraz dyspersyjnych cząstek wtopionych węglików WC. Największym przyrostem twardości odznaczają się stopy magnezu MCMgAIBZnl i MCMgAI6Znl z laserowo wtopionymi cząstkami WC, co spowodowane jest umocnieniem materiału w następstwie utwardzania dysper-syjnego. Warstwy wierzchnie odlewniczych stopów magnezu z laserowo wtopionymi cząstkami węglików uzyskują wyższe wartości prądów korozyjnych i niższe potencjały korozyjne, co wskazuje na ich słabszą odporność korozyjną w odniesieniu do materiału podłoża. Warstwy te ulegają korozji wżerowej.

EN

Structure, mechanical properties, as well as corrosion resistance of the surface layer Mg-AI-Zn casting magnesium alloys with the diversified aluminium concentration of MCMgAI3Znl, MCMgAI6Znl, MCMgAI9Znl, MCMgAH2Znl after laser surface treatment was presented in this work. Penetrated with WC carbide particles using laser fusion of the casting magnesium alloys carried out using high power diode laser (HPDL). It has been stated that the structure of the surface layer of the examined casting magnesium alloys solidified after the laser treatment demonstrates diversified morphology and consists of matrix with dendrites with the eutectic lamellae Mgl7AH2 and Mg in the inter-dendritic and dispersion spacing oj the fused WC carbide particles. The highest hardness increase, is demonstrated by the MCMgAI3Znl and MCMgAI6Znl magnesium alloys with the laser fused carbide particles, due to the consolidation of the material resulting from the dispersion hardening. The surface layers of the casting magnesium alloys with the laser fused carbide particles achieve higher values of the corrosion current and lower corrosion potential which indicate their weaker corrosion resistance in relation to the substrate material. These layers corrode to pitting corrosion.