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1

The Magnetoelectric Effect of a Ni0.3Zn0.62Cu0.08Fe2O4 - PbFe0.5Nb0.5O3 Multilayer Composite

Guzdek P., Sikora M., Góra Ł., Kapusta Cz.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 3

1011--1015

EN

The magnetoelectric effect in multiferroic materials has been widely studied for its fundamental interest and practical applications. The magnetoelectric effect observed for single phase materials like Cr2O3, BiFeO3, and Pb(Fe0.5Nb0.5)O3 is usually small. A much larger effect can be obtained in composites consisting of magnetostrictive and piezoelectric phases. This paper investigates the magnetoelectric effect of a multilayer (laminated) structure consisting of 6 nickel ferrite and 7 PFN relaxor layers. It describes the synthesis and tape casting process for Ni0.3Zn0.5Cu0.08Fe2O4 ferrite and relaxor PbFe0.5Nb0.5O3 (PFN). Magnetic hysteresis, ZFC - FC curves and dependencies of magnetization versus temperature for PFN relaxor and magnetoelectric composite were measured with a vibrating sample magnetometer (VSM) in an applied magnetic field up to 85 kOe at a temperature range of 10 – 400 K. Magnetoelectric effect at room temperature was investigated as a function of a static magnetic field (0.3 - 6.5 kOe) and the frequency of sinusoidal magnetic field (0.01 - 6.5 kHz). At lower magnetic field, the magnetoelectric coefficient increases slightly before reaching a maximum and then decreases. The magnetoelectric coefficient aME increases continuously as the frequency is raised, although this increase is less pronounced in the 1-6.5 kHz range. Maximum values of the magnetoelectric coefficient attained for the layered composites exceed about 50 mV/(Oe cm).

PL

Materiały kompozytowe wykazujące efekt magnetoelektryczny są obecnie szeroko badane zarówno dla celów poznawczych jak i aplikacyjnych. Szczególny nacisk kładzie się na kompozyty ferrytowo – relaksorowe, w których efekt magnetoelektryczny jest znacznie większy niż w materiałach jednofazowych. W opracowaniu przedstawiono technologię wytwarzania wielowarstwowego kompozytu ceramicznego składającego się z magnetycznych warstw ferrytu Ni0.3Zn0.62Cu0.08Fe2O4 rozdzielonych warstwami ferroelektryka PbFe0.5Nb0.5O3. Przedstawiono wyniki badań właściwości magnetycznych otrzymanego kompozytu. Badania te przeprowadzono przy użyciu magnetometru wibracyjnego w szerokim zakresie temperatur (10K- 400K) w polu magnetycznym dochodzącym do 85 kOe. Wykonano pomiary efektu magnetoelektrycznego w temperaturze pokojowej w zależności od częstotliwości zmiennego pola magnetycznego (0.01 - 6.5 kHz) oraz natężenia stałego pola magnetycznego (0.3 - 6.5 kOe). Współczynnik magnetoelektryczny najpierw rośnie, osiąga maksimum a następnie lekko maleje ze wzrostem natężenia stałego pola magnetycznego. Współczynnik magnetoelektryczny badanego kompozytu rośnie ze wzrostem częstotliwości sinusoidalnego zmiennego pola magnetycznego osiągając maksymalną wartość około 50 mV/(Oe cm).

2

Processing, Microstructure and Properties of Different Method Obtained Cu-Al2O3 Composites

Strojny-Nędza A., Pietrzak K.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 4

1301--1306

EN

Alumina/copper composites are used where high thermal conductivity, high absorption and dissipation of heat, high resistance to thermal fatigue and good frictional wear resistance are required. The properties of these composites depend on a number of factors including the content, shape and distribution of the ceramic phase, the method of their obtaining, as well as the conditions under which they are obtained. All these variables have influence on mentioned properties and, in consequence, on the future applications of the final material. The aim of this paper was to develop Cu /Al2 O3 composites, processed using two techniques, namely sintering (of Cu /Al2 O3 high-energy mixed powders) and tape casting (of slurry of the following composition: 1, 3 and 5 vol.% of Al2 O3 phase; the remaining part: Cu). The compositions were determined taking into consideration the planned applications. The paper presents newly developed technologies, the results of both microstructure investigations as well as of the measurements of selected physical and mechanical properties (microhardness, wear resistance, thermal conductivity etc.) and contains the analysis of the influence of selected techniques and processing conditions on the properties and the interface morphology between ceramic and copper.

PL

Kompozyty na bazie miedzi znajdują zastosowanie tam, gdzie jest wymagane: wysokie przewodnictwo cieplne, wysoka absorpcja i rozpraszanie ciepła, wysoka odporność na zmęczenie cieplne i dobra odporność na zużycie ścierne. Właściwości tych kompozytów zależą od wielu czynników tj. zawartości, kształtu i rozkładu fazy ceramicznej w metalowej osnowie jak również od samego sposobu (warunków) ich wytwarzania. Celem niniejszej pracy było otrzymanie kompozytów Cu-Al2 O3 stosując dwie techniki: spiekania mieszaniny proszków pod ciśnieniem oraz odlewanie folii kompozytowych (tape casting), laminowanie oraz końcowe spiekanie otrzymanych materiałów. Ze względu na przyszłe zastosowania tych kompozytów (m.in. elementy w układach turbin w samolotach) wytypowane zostały następujące składy: 99%ob j:Cu-1%ob j:Al2 O3 , 97%ob j:Cu-3%ob j: Al2 O3 , 95%ob j:Cu-5%ob j: Al2 O3 : W prezentowanej pracy przedstawiono dwie technologie otrzymania kompozytów na bazie miedzi. Przeprowadzone zostały badania mikrostruktury otrzymanych kompozytów ze szczególnym zwróceniem uwagi na możliwość pojawienia się warstwy przejściowej ceramika/metal. Przeprowadzone zostały również badania właściwości fizycznych (twardość, gęstość), badania właściwości cieplnych (dyfuzyjność cieplna, przewodnictwo cieplne) oraz badania właściwości mechanicznych (zużycie ścierne) otrzymanych kompozytów.

3

Casting of aluminium alloy strip using an unequal diameter twin roll caster

Haga T., Inui H., Watari H., Kumai S.

Archives of Materials Science and Engineering

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2008

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Vol. 29, nr 2

113-116

EN

Purpose: of this paper is to clear the property and ability of an unequal diameter twin roll caster to cast commercial size strip. Therefore, 400mm-width strip was cast as first step. Surface-condition, microstructure and mechanical property of the strip was investigated. Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster. This method was devised to realize easy operation of the twin roll casting and increase of casting speed. Findings: are that 400-width-strip of 3084, 5182 and 6022 could be cast at speed of 20 m/min. This strip was about 4 mm-thick. There were some defects on the surface. As cast strip could be cold-rolled down to sheet of 1 mm-thick. 180 degrees bending test was operated on the 6022 sheet after T4 heat treatment. Crack did not occurred at the outer surface when strip was bent at width-direction. Research limitations/implications: is that the quantity of the melt was 21kg and investigation of the properties was not enough for practical use. The larger weight of melt must be cast for production. Practical implications: are as below. The 400mm-width strip can be cast easily by the unequal diameter twin roll caster. This caster can be adapted to 3083, 5182 and 6022. Originality/value: as below. The economy sheet with 400mm width can be produced by the unequal diameter twin roll caster. 3083, 5182 and 6022 can be cast at the speed of 20m/min. The thickness of the strip was about 4mm.

4

High speed twin roll casting of Al-3Si-0.6Mg strip

Haga T., Ikawa M., Watari H., Kumai S.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

337--340

EN

Purpose: Purpose of this paper is to clear the possibility of high speed roll casting of thin strip of Al-3%Si-0.6%Mg alloy. Investigation of the mechanical properties of the roll cast Al-3%Si-0.6%Mg strip was purpose, too. Design/methodology/approach: Method used in the present study was high speed twin roll caster and low temperature casting. These methods were used to realize rapid solidification, and increase of casting speed. Findings: Findings are that Al-3%Si-0.6%Mg was could be cast at speed of 60 m/min. This strip was 3.1 mm-thick. As cast strip could be cold-rolled down to sheet of 1 mm-thick. 180 degrees bending test was operated on the sheet after T4 heat treatment and crack was not occurred at the outer surface. Research limitations/implications: Research limitation is that the width of the strip was 100 mm and investigation of the properties was not enough for practical use. Wider strip must be cast using the twin roll caster of the size for production. Practical implications: Practical implications are as below. The economy sheet for the auto mobile can be produced by the high speed twin roll caster. Al-3%Si-0.6%Mg can be used both the casting and plastic forming. Therefore, fractionation in the recycle of the aluminum alloy will becomes easy. The content of Fe in the recycled aluminum alloy increases. Fe becomes intermetallic of AlSiFe. Si for Mg2Si becomes deficient. 3%Si was enough for Mg2Si if AlSiFe was precipitated. Al-3%Si-0.6%Mg is suitable for recycle. Originality/value: The result means the roll cast Al-3%Si-0.6%Mg has ability to be used as the body sheet of the auto mobile.

5

High speed twin roll casting of 6016 strip

Haga T., Ikawa M., Watari H., Kumai S.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

371--374

EN

Purpose: of this paper is to clear the possibility of high speed roll casting of thin aluminum alloy strip. 6016 aluminum alloy is used for sheet metal of the automobile. Therefore, casting of 6016 was tried in this study. Castability and characteristics of roll cast 6016 strip were investigated. Design/methodology/approach: was a high speed twin roll caster. The high speed twin roll caster was designed to overcome the low castability of the twin roll caster. Findings: are as below. The 6016 could be cast at speed of 60 m/min. The thickness of the 6016 was 3 mm. The microstructure at as-cast and after T6 heat treatment was shown. The microstructure was very fine by the effect of the rapid solidification. The mechanical properties were investigated by the tension test and 180 degrees bending test. The as-cast strip could be cold rolled down to 1 mm without homogenization. The result of tension test (gage length 50mm) of T4 strip was as below, tensile stress was 242 MPa, proof stress was 123 MPa and elongation was 26%. There was no crack at the outer surface of 180-degree-bent strip until contact. This shows the strip endure the hem forming. Research limitations/implications: is the width of the strip was 100 mm. The test using a large scale twin roll caster must be operated. Practical implications: are as below. The mechanical properties of the roll-cast 6016 were enough for the sheet metal for the automobile. The low productivity of the twin roll caster could be improved, and economy 6016 strip was able to produce. Originality/value: is that 6016 strip could be cast at speed 60 m/min and this strip had good mechanical properties.

6

High speed roll casting of Mg alloy strip by a vertical type twin roll caster

Haga T., Watari H., Kumai S.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 15, nr 1-2

186--192

EN

Purpose: The possibility of high speed roll casting of AZ31, AM60 and AZ91 was investigated. Warm deep drawing of roll cast magnesium alloy was operated. and formability of roll cast magnesium strip was cleared. Design/methodology/approach: A vertical type high speed twin roll caster was used. The roll casting was operated in the air atmosphere. The casting speed was from 60 m/min up to 180 m/min. Low temperature casting was adopted to realize high speed casting. Findings: Strip thinner 3 mm with 100 width could be cast continuously. The casting ability became better with increasing content of Al. Roll cast Mg alloy strips could be hot-rolled down to 0.5 mm. AZ31 as-cast strip could be thinner down to 0.5 mm only by three times of hot rolling. Deep drawing was operated with three kinds of Mg alloy at 250°C, and LDR value was larger than 2.0. It was shown that deep drawing of AZ91 alloy for casting was possible. Research limitations/implications: There was tendency that cracks occurred at the center in the thickness direction as Al content increased. Practical implications: Sheet metal forming of magnesium alloy with high content Al can be realized. Originality/value: It was shown that possibility of high speed roll casting of magnesium alloy, and warm deep drawing of roll cast AZ91 strip.

7

Aluminum alloy semisolid strip casting using an unequal diameter twin roll caster

Haga T., Sakaguchi H., Inui H., Watari H., Kumai S.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 14, nr 1-2

157--162

EN

Purpose: A Purpose of the present study was to break through the disadvantage of the twin roll caster for aluminum alloy. They were slow casting speed and limitation of alloy. For example, the casting speed was slower than 5 m/min, and casting of hypereutectic Al-Si alloy was difficult. In order to break through the disadvantages, semisolid casting using an unequal diameter twin roll caster was tested its ability. Design/methodology/approach: The specification of the unequal diameter twin roll caster is as below. The diameter of the upper roll was 250 mm, and that of the lower roll was 1000 mm. The width of the roll was 100 mm. The semisolid slurry was made by a cooling slope. Findings: The microstructure of the strip became very fine. Especially, primary and eutectic Si became very fine. This was the effect of rapid solidification. As the result, the ductility of Al-16%Si was improved. Research limitations/implications: 6111 aluminum alloy strip was cast at speeds of 5, 10 and 20 m/min. This caster could cast the strip at the speeds higher than the conventional twin roll caster. Start of casting was very easy. The hypereutectic Al-16%Si alloy, which has wide freezing zone, could be cast in to the strip by the unequal diameter twin roll caster. This was the effect of the cooling of the strip on the lower roll. Originality/value: The roll cast Al-16mass%Si strip had good ductility, and could be cold rolled. Annealed 0.5 mm thick Al-16mass%Si could be bent at radius of 0.75mm.

8

Problem utleniania ciekłego stopu cynku z miedzią i tytanem podczas odlewania taśmy metodą ciągłą.

Wesołowski J., Ciura L., Kazana W.

Rudy i Metale Nieżelazne

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2001

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R. 46, nr 1

3-6

PL

Przedstawiono wyniki przeprowadzonych badań dotyczących zjawiska okresowego występowania dużej intensywności utleniania stopu cynk-miedź-tytan w warunkach odlewania z tego stopu taśmy metodą ciągłą. Ustalono skład chemiczny fazy niemetalicznej dobrze zwilżonej przez fazę metaliczną stopu. Określono prawdopodobne przyczyny nasilonego utleniania ciekłego stopu na drodze jego transportu do maszyny odlewniczej.

EN

Investigation results of the phenomenon of periodical, great oxidation intensity of the zinc-copper-titanium alloy, at continuous strip casting of that alloy, are presented. The chemical composition of the non-metallic phase of the alloy was determined. The probable cause of the intensified oxidation of the molten alloy, during its transport to the casting machine, has been defined.