Livarski vestnik 63/2016 nr. 3
Mustafa Acarer1, Gökhan Arıcı1, Fatih Aydın2, Mesut Uyaner1, Murat Çolak3, Ramazan Kayıkçı4, 1Selcuk University, Konya-TURKEY, 2Karabuk University, 3Bayburt University, Faculty of Engineering, Bayburt, TURKEY, 4Sakarya University, TURKEY
PRODUCTION OF 3CR-3W STEEL BY INVESTMENT CASTING
D. Sojer1, Ž. Erman1, I. Anžel2, M. Brunčko1,2, 1Magneti Ljubljana d.d., Ljubljana, Slovenia,
2University of Maribor, Faculty of Mechanical Engineering, Maribor, Slovenia,
CENTRIFUGAL ATOMIZATION OF ND–FE–B FLAKES USED FOR PRODUCTION OF PERMANENT MAGNETS
Nadežda M. Talijan1, Vladan R. Ćosović1, Aleksandar R. Ćosović2, Dragana T. Živković3, 1University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Belgrade, Serbia, 2Institute for Technology of Nuclear and Other Mineral Raw Materials, Belgrade, Serbia, 3Technical Faculty in Bor, University of Belgrade, Bor, Serbia
M. Petrič1, J. Medved1, S. Kastelic1, A. Križman3, P. Mrvar1, 1Univerza v Ljubljani, Naravoslovnotehniška fakulteta, 3Univerza v Mariboru (SI)
MEASUREMENT OF DIMENSIONAL CHANGES OF ALSI ALLOYS DURING SOLIDIFICATION
Mustafa Acarer1, Gökhan Arıcı1, Fatih Aydın2, Mesut Uyaner1, Murat Çolak3, Ramazan Kayıkçı4, 1Selcuk University, Konya-TURKEY, 2Karabuk University, 3Bayburt University, Faculty of Engineering, Bayburt, TURKEY, 4Sakarya University, TURKEY
PRODUCTION OF 3CR-3W STEEL BY INVESTMENT CASTING
Abstract
In this study, 3CrW steel was produced by casting. 3CrW steel alloyed with Co and Ta. The effect of heat treatment on microstructure and hardness of samples was examined. It was observed that the heat treatments performed at different temperatures change the microstructure and hardness of the materials.
D. Sojer1, Ž. Erman1, I. Anžel2, M. Brunčko1,2, 1Magneti Ljubljana d.d., Ljubljana, Slovenia,
2University of Maribor, Faculty of Mechanical Engineering, Maribor, Slovenia
CENTRIFUGAL ATOMIZATION OF ND–FE–B FLAKES USED FOR PRODUCTION OF PERMANENT MAGNETS
Abstract
Nd–Fe–B-type permanent magnets are widely used in applications that require a high magnetic energy product in order to reduce weight. Automotive industry, hard drives, or wind turbines are examples of applications where their use can be found. Conventional casting techniques cause the formation of -Fe and large RE-rich regions. On the other hand, techniques like strip casting, melt-spinning, and centrifugal atomization, produce homogeneous and fine scaled microstructures.
This paper discusses the application of rapid solidification by the centrifugal atomization method for preparation of Nd–Fe–B flakes. The effect of alloy composition and various process parameters of centrifugal atomization on the microstructure of rapidly solidified Nd–Fe–B alloy were investigated. The microstructures and the phase composition were examined by metallographic techniques, namely optical and scanning electron microscopy. Additionally, the influence of the processing methods on the microstructures of as-cast flakes and subsequent magnetic properties of the prepared magnets will be discussed.
Nadežda M.Talijan1, Vladan R. Ćosović1, Aleksandar R. Ćosović2, Dragana T. Živković3, 1University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Belgrade, Serbia, 2Institute for Technology of Nuclear and Other Mineral Raw Materials, Belgrade, Serbia, 3Technical Faculty in Bor, University of Belgrade, Bor, Serbia
INNOVATIVE APPROACH ON IMPROVEMENT OF METAL OXIDE DISPERSION AND STRUCTURE DEPENDENT PROPERTIES OF Cd FREE SILVER/METAL OXIDE ELECTRICAL CONTACT MATERIALS
Abstract
In the present study an innovative attempt has been made to improve dispersion of metal oxides (MeO) in Ag-MeO electrical contact materials by introducing metal oxide nanoparticles (SnO2, ZnO, In2O3, Bi2O3, and WO3), into silver matrix and preparation of nanocomposite powders by template method using soluble starch as template material. The morphology and microstructure of the prepared Ag-MeO composite powders were studied using SEM and FESEM. The obtained results show that the prepared composite powders exhibit high degree of dispersion of metal oxide nanoparticles and high uniformity. Furthermore, it was found that they are very suitable for further production of Ag-MeO electrical contact materials and that the benefits are primarily illustrated as an improvement of homogeneity of microstructure and structure dependent properties. The prepared and studied final Ag-SnO2 and Ag-ZnO contact materials exhibit finer dispersion of oxides, higher hardness, higher density, lower porosity and slightly lower electrical conductivity compared to corresponding conventionally prepared materials, however still within the required range for commercial contact material of this type.
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M. Petrič1, J. Medved1, S. Kastelic1, A. Križman3, P. Mrvar1, 1Univerza v Ljubljani, Naravoslovnotehniška fakulteta, 3Univerza v Mariboru (SI)
MEASUREMENT OF DIMENSIONAL CHANGES OF ALSI ALLOYS DURING SOLIDIFICATION
Abstract
Solidification of AlSi12 alloy was described using different techniques such as thermal analysis, dilatometric analysis in accordance with thermodynamic calculation carried out by Thermo-Calc software. Metallographic investigation was made using optic and scanning electron microscopy (SEM). Phase analysis was done by energy dispersive spectroscopy (EDS). The aim of the paper is to investigate dimensional changes of a casting during solidification. Four specimens were analysed. First one was AlSi12 alloy without additions, second is grain refined with AlTi5B1 master alloy, third one modified with AlSr10 master alloy and the last one with both master alloys. Microstructures were different in terms of grain size of αAl phase and size of βSi particles. Dilatometric analysis has shown differences in shrinkage of basic alloy and modified alloys where shrinkage is lower.