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Wyszukujesz frazę "Kvackaj, T." wg kryterium: Autor


Wyświetlanie 1-6 z 6
Tytuł:
The Porosity Evaluation during ECAP in Aluminium PM Alloy
Autorzy:
Bidulská, J.
Kvačkaj, T.
Bidulský, R.
Actis Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/1418956.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.07.Bc
81.20.Ev
81.40.-z
Opis:
The main aim of this paper is to show porosity evolution during application of various processing conditions including pressing, sintering and equal channel angular pressure. An aluminium based powder (Al-Mg-Si-Cu-Fe) was used as investigated material. After applying different pressing pressures (400 and 600 MPa), specimens were dewaxed in a ventilated furnace at 400C for 60 min. Sintering was carried out in a vacuum furnace at 610C for 30 min. The specimens were processed by single equal channel angular pressure pass. A significant disadvantage of powder metallurgy processing methods is the presence of porosity. Pores act as crack initiators and, due to their presence, the distribution of stress is inhomogeneous across the cross-section and leads to reduction of the effective load bearing area. The equal channel angular pressure process, causing stress distribution in deformed specimens, made the powder particles to squeeze together to such an extent that the initially interconnected pores transform to small isolated pores. The proposed safety diagram includes the combined effect of stress and strain behaviour during equal channel angular pressure. The "safety line" eliminates and quantifies the effect of large pores as a potential fracture initiation sites with respect to the mechanical viewpoint.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 553-556
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the Fracture Surfaces of New Development Insulated Iron Powder Compounds
Autorzy:
Bidulský, R.
Bidulská, J.
Kvačkaj, T.
Actis Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/1201089.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
81.20.Ev
81.40.Np
Opis:
Goal of the present paper is the analysis of the fracture surfaces of an Insulated Iron Powder Compound (IIPC) with different additions of aluminium alloy (0.25, 0.5 and 0.75 wt.%), in order to improve the mechanical properties, evaluated as the transverse rupture strength (TRS) with sufficient magnetic properties (mainly represented by the iron loss and coercivity force). Investigation of microstructure and porosity development concluded that improvements in bending strength and impact values require the reduction of surface oxides during the heat treatment, in order to get a proper load bearing area between the adjacent particles.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 154-155
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Fracture Surfaces of Soft Magnetic Materials
Autorzy:
Bidulská, J.
Kvačkaj, T.
Bidulský, R.
Actis Grande, M.
Ferraris, L.
Powiązania:
https://bibliotekanauki.pl/articles/1533971.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
81.20.Ev
81.40.Np
Opis:
The present paper focused on the analysis of the fracture surfaces of a new development insulated iron powder compound with the addition of the aluminium alloy in order to improve the mechanical properties. Results show that in the pressed state, mainly pores act as crack initiators and due to their presence the distribution of stress is inhomogeneous across the cross-section and leads to the reduction of the effective load bearing area. Investigation of fracture surfaces concluded that improvements in bonding during the pressing process and heat treatment can be helpful in the development of soft magnetic materials to give a suitable combination between pressing pressure, annealing temperature and time as well as magnetic properties.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 800-801
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of the critical pore sizes in sintered and ecaped aluminium 6XXX alloy
Przewidywanie powstawania porowatości podczas wyciskania w kanale kątowym stopu aluminium otrzymanego metodą proszkową
Autorzy:
Bidulská, J.
Kvačkaj, T.
Pokorný, I.
Bidulský, R
Actis Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/353976.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminium alloy
ECAP
porosity
critical pore sizes
microstructure
fracture
stop aluminium
wyciskanie w kanale kątowym
porowatość
mikrostruktura
pękanie
Opis:
The main aim of this paper is to investigate, by means of comparison of experimental studies and mathematical models, the evolution of porosity as consequence of pressing, sintering and ECAPping an aluminium based powder (6xxx). After applying the compacting pressure, specimens were dewaxed in a ventilated furnace at 400º for 60 min. Sintering was carried out in a vacuum furnace at 610ºC for 30 min. The specimens were then ECAPed for 1 pass. The 2-dimensional quantitative image analysis was carried out by means of SEM and OM for the evaluation of the aforementioned characteristics. Results show the effect of processing parameters on the fracture/microstructure behaviour of the studied aluminium PM alloy. Quantitative image analysis, as well as fractographic interpretation and microstructure identification of weak sites in the studied aluminium PM alloy, provide a reliable and reproducible statistical procedure for the identification of the critical pore sizes.
Głównym celem pracy jest badanie zmian porowatości podczas prasowania, spiekania i wyciskania przez kanał katowy proszku na bazie aluminium (Ai-Mg-Si-Cu-Fe) za pomocą eksperymentu i symulacji numerycznych. Po przyłożeniu ciśnienia podczas zagęszczania usuwano lepiszcze z próbek w piecu w temperaturze 400ºC przez 60 minut. Spiekanie prowadzono w piecu próżniowym w temperaturze 610ºC przez 30 min. Próbki następnie były wyciskane przez kanał kątowy w jednym przejściu. Dwuwymiarowa ilościową analizę obrazu przeprowadzono za pomocą skaningowej mikroskopii elektronowej i mikroskopii optycznej w celu oceny wyżej wymienionych właściwości. Wyniki opisują wpływ parametrów procesu na pękanie/ mikrostrukturę badanego proszku stopu aluminium. Ilościowa analiza obrazu, jak równiez mikrostruktury w badanym stopie proszku aluminium zapewniają wiarygodne i statystycznie powtarzalne procedury dla identyfikacji miejsc inicjacji pękania.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 2; 371-375
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of ECAP-Back Pressure on the Porosity Distribution
Autorzy:
Bidulská, J.
Kvačkaj, T.
Kočiško, R.
Bidulský, R.
Actis Grande, M.
Donič, T.
Martikán, M.
Powiązania:
https://bibliotekanauki.pl/articles/1538174.pdf
Data publikacji:
2010-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.20.Ev
81.40.-z
81.70.Fy
Opis:
The main aim of this paper is to show how back pressure equal channel angular pressing (ECAP-BP) influences the porosity distribution in powder metallurgy (PM) aluminium alloys. When back pressure is applied, the accumulation of damage in deformed samples decreases due to the fact that the shear strain takes place under predominantly compressive stresses. Consequently, ECAP-BP influences the porosity distribution in terms of the severe shear deformation involved. According to the obtained results, interesting applications for this new progressive method in physical and metallurgical research fields are shown.
Źródło:
Acta Physica Polonica A; 2010, 117, 5; 864-868
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Microstructural and Mechanical Properties after Cold Rolling of an Electro-Sinter-Forged Cu-Sn Alloy
Autorzy:
Gobber, F. S.
Bidulská, J.
Fais, A.
Franchini, F.
Bidulský, R.
Kvačkaj, T.
Actis Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/352541.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Electro-Sinter-Forging
powder metallurgy
CuSn15
rolling
Opis:
Traditional press and sinter processes have gained in the last decades more and more importance in the manufacturing of high volume and precise mechanical components especially in the field of iron based powders. In recent years, the reductions of processing times and temperatures were spotted as critical targets to increase productivity and reduce energy consumption. Electric current assisted sintering (ECAS) technologies have always been seen as an alternative to traditional furnace based sintering techniques and have been the target of different researches with the specific purpose of reducing both operational times and costs. The aim of the present study is to investigate the effect of an innovative process called Electro Sinter Forging (ESF) applied to CuSn15 powders. Thanks to a very short processing time (less than 1 second to densify loose powders), this process is able to retain a very small grain size, thus enhancing mechanical properties of the processed materials. Furthermore, to the authors knowledge, cold – rolled electro – sinter – forged alloys has never been investigated before. First of all, bars were electro – sinter – forged and subsequently characterized in the as sinter – forged condition. The observation of microstructure evidenced an extremely fine microstructure and a reduced degree of porosity. Afterwards, bars were cold rolled after different reduction ratios; macrostructural integrity of the rolled bars was assessed before evaluating the effects of cold rolling on the sinter – forged microstructure.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 2; 787-792
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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