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1

The Influence of Variable Parameters of Horizontal Continuous Casting on the Structure of AlCu4MgSi Alloy Ingots

Nuckowski P. M., Wróbel T.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 1

196--202

EN

The article presents results of research on the influence of variable parameters of horizontal continuous casting on the structure of AlCu4MgSi (EN AW-2017A) alloy ingots. The special character of the process allows for a continuous change of some of its parameters, namely, of the casting speed and of the rate of the cooling fluid flow thorough the crystallizer. These parameters have a significant impact on the crystallization process of the liquid metal. Depending on the cooling rate, intensity of the convection inside the solidifying alloy, and its chemical composition, there may arise some differences in the structure of the cast. In this study, ingots obtained at different casting speeds have been analyzed. The research methodology, based on light microscopy and electron microscopy (SEM), as well as energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), allowed for a thorough examination of the structure of the studied materials. The results were shown that an increase in the ingot casting speed leads to an increase in the average grain surface area.

2

Evaluation of the Possibility of Applying Spatial 3D Imaging Using X-Ray Computed Tomography Reconstruction Methods for Quantitative Analysis of Multiphase Materials

Matysik P., Chojnacki M., Jóźwiak S., Czujko T., Lipiński S.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 4

2663--2670

EN

In this paper the possibility of using X-ray computed tomography (CT) in quantitative metallographic studies of homogeneous and composite materials is presented. Samples of spheroidal cast iron, Fe-Ti powder mixture compact and epoxy composite reinforced with glass fibers, were subjected to comparative structural tests. Volume fractions of each of the phase structure components were determined by conventional methods with the use of a scanning electron microscopy (SEM) and X-ray diffraction (XRD) quantitative analysis methods. These results were compared with those obtained by the method of spatial analysis of the reconstructed CT image. Based on the comparative analysis, taking into account the selectivity of data verification methods and the accuracy of the obtained results, the authors conclude that the method of computed tomography is suitable for quantitative analysis of several types of structural materials.

PL

W pracy przedstawiono możliwość wykorzystania rentgenowskiej tomografii komputerowej (CT) w ilościowych badaniach metalograficznych materiałów jednorodnych oraz kompozytowych. Badaniom porównawczym poddano wypraskę mieszaniny proszkowej Fe – Ti, żeliwo sferoidalne, a także kompozyt epoksydowy zbrojony włóknami szklanymi. Udział objętościowy poszczególnych składników strukturalnych określano za pomocą klasycznych metod stereologicznych z wykorzystaniem skaningowej mikroskopii elektronowej (SEM) oraz metodami rentgenowskiej analizy ilościowej (XRD). Uzyskane typowymi metodykami wyniki porównano z rezultatami otrzymanymi za pomocą metody przestrzennej analizy obrazu tomografii komputerowej. Na podstawie przeprowadzonych analiz, biorąc pod uwagę selektywny sposób weryfikacji danych oraz dokładność uzyskiwanych wyników, można stwierdzić przydatność wykorzystania metody tomografii komputerowej, w obszarze ilościowej analizy strukturalnej szerokiego spektrum materiałów konstrukcyjnych.

3

Effect of Bi2O3 excess on morphology and structure of BiNbO4 ceramics

Czekaj D., Lisińska-Czekaj A., Osińska K., Biernacki K.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 4

1317--1321

EN

Goal of the present research was to fabricate BiNbO4 ceramics from the mixture of powders by the solid state reaction route and pressureless sintering at various temperatures (TS =870°C and TS =910°C) and study microstructure, phase composition and crystalline structure of BiNbO4 ceramics. Four batches were fabricated and examined, namely the one fabricated from the stoichiometric mixture of reagent - grade oxide powders, viz. Bi2 O3 and Nb2 O5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2 O3 . It was found that apart from the main orthorhombic α-BiNbO4 phase additional phases, namely tetragonal Bi5Nb3O15, and cubic Bi3 NbO7 are possible to form from the mixture of bismuth oxide and niobium oxide. It was found that α-BiNbO4 ceramics exhibited the orthorhombic symmetry identified as Pnna (52). However, small differences in elementary cell parameters were found for the samples sintered from stoichiometric and non-stoichiometric mixture of initial powders.

PL

Celem niniejszej pracy było wytworzenie ceramiki BiNbO4 z mieszaniny proszków metodą reakcji w fazie stałej z następującym spiekaniem swobodnym przeprowadzonym w temperaturze TS =870°C i TS =910°C. Ponadto zbadano wpływ zawartości Bi2 O3 na mikrostrukturę, skład chemiczny, fazowy i strukturę krystaliczną ceramiki BiNbO4. Mieszaniny tlenków wyjściowych Bi2O3 i Nb2O5 przygotowano zarówno w ilości stechiometrycznej, jak i z nadmiarem tlenku bizmutu odpowiednio 3%mol, 5%mol i 10%mol. Na podstawie rentgenowskiej fazowej analizy stwierdzono, że oprócz głównej fazy rombowej α-BiNbO4 wytworzona ceramika zawiera niewielkie domieszki fazy tetragonalnej Bi5NB3O15 i regularnej Bi3NbO7. Stwierdzono, że faza α-BiNbO4 wykazuje symetrię rombową opisywaną jako Pnna (52), natomiast niestechiometryczność mieszaniny proszków wyjściowych powoduje niewielkie różnice parametrów komórki elementarnej.

4

Development of the fundamentals of melting and casting technology of Al-Me (Cr, Ni, Mo, W, Ti) master alloys used for modification of microstructure in silumins

Piątkowski J.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 2

17-20

EN

The study presents the technological backgrounds of the process of melting and casting Al-Cr, Al-Ni, Al-Mo, Al-W and Al-Ti master alloys, used as refiners of the microstructure of cast silumins. Basing on the analysis of phase equilibrium diagrams for an Al-Me (Cr, Ni, Mo, W, Ti) system at a temperature of 900oC, the characteristic intermetallic phases of AlxMey were investigated. Due to their similarity with Al and Si in respect of both structure and lattice arrangement, these phases may act as heterogeneous nuclei and promote solution hardening during, e.g., heat treatment. Using the method of thermal analysis ATD, the temperature was plotted in function of time, and then the characteristic values of the solidification parameters of master alloys were read out from the respective curves.