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Wyświetlanie 1-23 z 23
Tytuł:
Correlation between Microstructure/Fracture Surfaces and Material Properties
Autorzy:
Bidulský, R.
Bidulská, J.
Actis Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/1418955.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.20.Ev
81.40.-z
62.20.mm
62.25.Mn
Opis:
The present paper deals with the evaluation of the effect of different vacuum heat treatments on the microstructure and fracture surfaces of a low alloyed sintered Fe-[1.5Cr-0.2Mo]-0.6C steel, in correlation with the mechanical and plastic properties achieved. The heat treatment consists of the sintering process in vacuum furnace at 1393 K for 1800 s, followed by different cooling conditions and an integrated final tempering at 473 K for 3600 s. The average cooling rates, calculated in the range of 1393 K to 673 K, were 0.1, 0.235, 3, and 6 K/s, respectively. Vacuum heat treatment is supporting the bainitic-martensitic microstructure, the higher the faster cooling rate applied. This provides a marked increase in strength coupled to a decrease in ductility. The decrease of the impact energy after heat treatment is justified by the microstructural changes, especially if a part of bainite is converted to brittle martensite. Samples with bainitic microstructure presented higher impact energies than those with martensitic microstructure. This is fully confirmed by the fracture surface analysis at higher magnification, revealing three main micromechanisms of fracture: brittle, ductile and quasi-cleavage.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 548-552
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of microstructure discontinuities in the soft magnetic composites with aluminium alloy addition
Rola niejednorodności mikrostruktury w magnetycznie miękkich kompozytach z dodatkiem stopu aluminium
Autorzy:
Bidulský, R
Bidulská, J.
Actis Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/351805.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
soft magnetic composites
insulated iron powder compound
aluminium alloy
coercivity
specific losses
magnetycznie miękkie kompozyty
materiał IIPC
stop aluminium
straty
Opis:
The paper focuses on the effect of both the aluminium alloy addition and microstructural inhomogeneties on the magnetic behaviour of soft magnetic materials tested at low frequencies. The IIPC material (base on the commercial Somaloy 1P powder) has been blended with different amounts of commercially aluminium alloy Alumix 321 (0, 5 and 10 wt %). Specimens with a different green density were obtained by pressing at a pressure in the range from 400 to 800 MPa. Different thermal treatments (in air or nitrogen at the maximum temperature of 500ºC for 30 min) were carried out on the evaluated systems. The microstructure investigation revealed that for materials with high aluminium alloy contents, pores are located nearby or around the aluminium alloy particles. The heat treatment regime resulted in a coarse-grained structure with a small number of inclusions within the grains and at the grain boundaries. The comparison of the results indicated that the magnetic properties were considerably dependent on the microstructural inhomogeneities.
Przedmiotem pracy jest wpływ dodatku stopu aluminium oraz niejednorodności mikrostruktury na właściwości magnetyczne magnetycznie miękkich materiałów badanych przy niskich częstotliwościach. Materiał IIPC (na bazie komercyjnego proszku Somaloy 1P) został zmieszany z różnymi ilościami komercyjnego stopu aluminium ALUMIX 321 (0, 5 i 10% wag.). Próbki o różnych gęstościach nasypowych prasowano stosując ciśnienie w zakresie od 400 do 800 MPa. Zastosowano różne obróbki cieplne (w powietrzu i azocie) ustalając maksymalną temperaturę 500ºC. Badania mikrostruktury pokazały, że dla materiałów o wysokiej zawartości stopu aluminium, pory sa w pobliżu lub otaczają cząstki stopu aluminium. W wyniku obróbki cieplnej tworzy się gruboziarnista struktura z minimalną liczbą wtraceń wewnątrz ziaren i na ich granicach. Porównanie wyników pokazuje, ąe właściwości magnetyczne zaleza w znacznym stopniu od niejednorodności mikrostruktury.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 2; 365-370
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Densification Process and Structure of PM Al-Mg-Si-Cu-Fe and Al-Zn-Mg-Cu-Sn Alloys
Analiza procesu zagęszczania i struktury spiekanych stopów Al-Mg-Si-Cu-Fe i Al-Zn-Mg-Cu-Sn
Autorzy:
Bidulský, R
Bidulská, J.
Actis Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/355248.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
powder metallurgy
aluminium alloy
compressibility
microstructure
metalurgia proszków
stop aluminium
ściśliwość
mikrostruktura
Opis:
The paper is focused on the role of the pressing pressure on the densification behaviour of PM aluminium alloys. Commercially aluminium based powders Al-Mg-Si-Cu-Fe and Al-Zn-Mg-Cu-Sn were used as materials to be investigated. The apparent density of the powder mixes was determined according to MPIF St. 04. A set of cylinder test specimen 55x10x10 mm3 was uniaxially pressed in a floating hardened steel die. Compaction pressures ranged from 50 MPa up to 700 MPa. Considering the densification of metal powders in uniaxial compaction, quantification of aluminium compaction behaviour was performed. The compressibility behaviour was evaluated, considering the effect on specimens, as well as on their microstructure. The development of compressibility values with pressing pressure enables to characterize the effect of particles geometry and matrix plasticity on the compaction process.
Przedmiotem pracy jest wpływ ciśnienia prasowania na zagęszczanie proszków stopów aluminium. Materiałem badanym były komercyjne proszki aluminium Al-Mg-Si-Cu-Fe I Al-Zn-Mg-Cu-Sn. Gęstość pozorna mieszanek proszków określono według MPIF St.04. Cylindryczne próbki 55x10x10 mm3 ściskane były jednokierunkowo w samonastawnej matrycy z hartowanej stali. Nacisk wahał się od 50 MPa do 700 MPa. Biorąc pod uwagę zagęszczenie proszków metali w trakcie prasowania jednoosiowego, przeprowadzono kwantyfikacje zagęszczania aluminium. Oceniono zachowanie ściśliwości biorąc pod uwagę wpływ na próbki, jak również na ich mikrostrukturę. Zestawienie wartości ściśliwości z ciśnieniem prasowania pozwala scharakteryzować wpływ geometrii cząstek i plastyczności matrycy na proces prasowania.
Źródło:
Archives of Metallurgy and Materials; 2014, 59, 1; 17-23
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of the high-temperature behaviour of aluminium alloy EN AW 2014
Wysokotemperaturowe zachowanie stopu aluminium EN AW 2014
Autorzy:
Bidulská, J.
Pokorný, I.
Kvačkaj, T.
Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/352627.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stopy aluminium
naprężenie płynięcia
równanie konstytutywne
aluminium alloy
flow stress
constitutive equation
hot working
Opis:
The high-temperature behaviour of aluminium alloy EN AW 2014 was investigated in a wide range of deformation temperatures and strain rates. The influence of strain rate and temperature on the peak stress was analysed using the conventional constitutive equation (relating strain rate, flow stress, and temperature) and by means of precise definition of the peak stress value, in the non-linear regression model. Moreover, a study on apparent activation energy of EN AW 2014 stabilized by zirconium was carried out using Arrhenius-type plot. The stress-strain curves exhibit rapid increase up to the peak value followed by a gradual softening up to the material fracture, without the steady state usually observed before the fracture. In terms of formability maps, the presented experimental results exhibit a decrease of ductility, respectively with an increase of strain rate and a decrease of temperature, respectively.
Wysokotemperaturowe zachowanie stopu aluminium EN AW 2014 badane było w szerokim zakresie temperatur i predkości odkształcenia. Wpływ prędkości odkształcenia i temperatury na maksymalne naprężenie analizowany był z użyciem konwencjonalnego podstawowego równania (wiazacego predkość odkształcenia, naprezenie płyniecia i temperature) oraz za pomocą precyzyjnej definicji wartości maksymalnego naprężenia w modelu regresji nieliniowej. Ponadto, analiza obserwowanej energii aktywacji stopu EN AW 2014 stabilizowanego cyrkonem przeprowadzono z użyciem wykresu typu Arrheniusa. Krzywe naprężenie-odkształcenie wykazują gwałtowny wzrost do maksymalnego naprężenia, po którym następuje stopniowe mięknięcie aż do zerwania materiału, bez obszaru stałego zwykle obserwowanego przed zerwaniem. Jesli chodzi o mapy plastycznosci, przedstawione wyniki doświadczalne wykazują spadek plastycznosci, odpowiednio ze wzrostem szybkości odkształcenia oraz ze spadkiem temperatury.
Źródło:
Archives of Metallurgy and Materials; 2011, 56, 4; 981-981
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the torsion test in calculating the extrusion force
Zastosowanie testu skręcania w obliczeniach siły wyciskania
Autorzy:
Pernis, R.
Bidulska, J.
Kvačarkaj, T.
Pokorny, I.
Powiązania:
https://bibliotekanauki.pl/articles/354146.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
siła wyciskania
test skręcania
stopy aluminium
extrusion force
torsion test
aluminium alloy
Opis:
The paper deals with the calculation of the extrusion force using the results of the torsion test of aluminium alloy EN AW-2014. The mathematical model for the calculation of the extrusion force requires the knowledge of the functional relationship between the yield stress and the temperature, the deformation and the deformation rate. Based on the proposed mathematical model for the calculation of the yield stress, the functional relationship was derived to determine the extrusion force in the hot extrusion of semi-products of aluminium alloy EN AW-2014.
Źródło:
Archives of Metallurgy and Materials; 2011, 56, 1; 81-85
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
New Approach In The Properties Evaluation Of Ultrafine-Grained OFHC Copper
Nowe podejście do oceny właściwości ultra drobnoziarnistej miedzi OFHC
Autorzy:
Kvačkaj, T.
Kováčová, A.
Bidulská, J.
Bidulský, R.
Kočičko, R.
Powiązania:
https://bibliotekanauki.pl/articles/958234.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
OFHC copper
UFG
ECAP
strain rate
fractography
wear resistance
miedź OFHC
szybkość odkształcenia
fraktografia
odporność na zużycie
Opis:
In this study, static, dynamic and tribological properties of ultrafine-grained (UFG) oxygen-free high thermal conductivity (OFHC) copper were investigated in detail. In order to evaluate the mechanical behaviour at different strain rates, OFHC copper was tested using two devices resulting in static and dynamic regimes. Moreover, the copper was subjected to two different processing methods, which made possible to study the influence of structure. The study of strain rate and microstructure was focused on progress in the mechanical properties after tensile tests. It was found that the strain rate is an important parameter affecting mechanical properties of copper. The ultimate tensile strength increased with the strain rate increasing and this effect was more visible at high strain rates (έ~102s−1) . However, the reduction of area had a different progress depending on microstructural features of materials (coarse-grained vs. ultrafine-grained structure) and introduced strain rate conditions during plastic deformation (static vs. dynamic regime). The wear behaviour of copper was investigated through pin-on-disk tests. The wear tracks examination showed that the delamination and the mild oxidational wears are the main wear mechanisms.
W pracy zbadano szczegółowo statyczne, dynamiczne i tribologiczne właściwości ultra drobnoziarnistej (UFG) beztlenowej miedzi o wysokiej przewodności cieplnej (OFHC). W celu oceny właściwości mechanicznych przy różnych szybkościach odkształcenia, miedź OFHC badano za pomocą dwóch urządzeń w warunkach statycznych i dynamicznych. Ponadto miedź poddano dwóm różnym sposobom przetwarzania, co umożliwiło badanie wpływu struktury. Badanie szybkości odkształcenia i mikrostruktury koncentrowało się na zmianie właściwości mechanicznych po próbie rozciągania. Stwierdzono, że szybkość odkształcania jest ważnym parametrem wpływającym na właściwości mechaniczne miedzi. Wytrzymałość na rozciąganie wzrosła ze wzrostem szybkości odkształcenia i ten efekt był bardziej widoczny przy dużej szybkości odkształcania (ε~102s−1) . Jednak zmniejszenie obrazu przebiegało inaczej w zależności od cech mikrostruktury materiałów (struktura gruboziarnista a struktura ultra drobnoziarnista) i zadanych warunków szybkości odkształcenia podczas odkształcenia plastycznego (warunki statyczne a warunki dynamiczne). Zużycie miedzi badano za pomocą testów zarysowania. Badanie ścieżek zużycia wykazało, że delaminacja i umiarkowane utlenienie to główne mechanizmy zużycia.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2A; 605-614
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Material Recovery of OFHC Cu and FeSi Steel after Processing by Plastic Deformations
Autorzy:
Kvackaj, T.
Kocisko, R.
Bidulska, J.
Luptak, M.
Kovacova, A.
Powiązania:
https://bibliotekanauki.pl/articles/1032938.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.82.Bg
07.20.Mc
81.20.Wk
62.20.F-
81.40.Ef
Opis:
The influence of thermoplastic processes through severe plastic deformations carried out at ambient temperature and through rolling carried out at cryogenic temperature on the recovery for two types of materials was investigated. As experimental materials, there were used oxygen free high conductivity copper and FeSi steel presenting materials with middle and high stacking fault energy, respectively. Both materials have been previously investigated, however mainly considering their material properties. In this study, oxygen free high conductivity Cu was processed by 13 passes through equal channel angular rolling which belongs to the severe plastic deformations group of methods. The rolling of FeSi steel at ambient and cryogenic temperatures was performed using a laboratory duo rolling mill, samples were rolled only by one pass. The aim of this study was to insert the strain to the materials with different stacking fault energy (middle and high) under ambient and cryogenic thermal conditions, respectively, and subsequently to observe the influence of stored energy on structural recovery of materials through differential scanning calorimetry method. This study implies that the recovery process characterized by the mobility of structural defects begins earlier for FeSi steel compared to oxygen free high conductivity Cu.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1315-1318
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effects of Chemical Composition on Soft Magnetic Materials Behaviour
Autorzy:
Bidulský, R.
Actis Grande, M.
Ferraris, L.
Ferraris, P.
Bidulská, J.
Powiązania:
https://bibliotekanauki.pl/articles/1533981.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
81.20.Ev
81.40.Rs
Opis:
The main aim of the presented work was to study the effects of chemical composition on the magnetic properties (in terms of B-H characteristics) of an insulated iron powder compound with various addition of the aluminium alloy (0, 5 and 10 wt%). The magnetic properties of the powder were significantly influenced by density and "sintering" effects. The addition of aluminium alloy maintaining suitable values of coercive force, remanence and core losses; this makes the modified insulated iron powder compound a promising soft magnetic material in several applications.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 802-803
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:
Porosity behaviour of insulated iron powder compounds
Autorzy:
Bidulská, J.
Bidulský, R.
Petroušek, P.
Fedoriková, A.
Katreničová, I.
Pokorný, I.
Powiązania:
https://bibliotekanauki.pl/articles/1050774.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
81.20.Ev
81.40.Np
Opis:
The goal of the present paper is to determine the porosity behavior of new development insulated iron powder compounds without and with different additions of aluminum alloy Alumix 321 (5 and 10 wt%). A significant disadvantage of PM processing 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 the reduction of the effective load bearing area. Quantitative image analysis of investigated material treats pores as isolated plane two-dimensional objects in solid surroundings. To describe the dimensional and morphological porosity characteristics, the dimensional characteristic D_{circle} and the morphological characteristics f_{shape} and f_{circle} were explored. Both the morphology and the distribution of pores shows a significant effect on the cold welding or appropriate bonds between adjacent particles.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1384-1386
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microdeformation Processes in Soft Magnetic Compounds
Autorzy:
Bidulský, R.
Bidulská, J.
Petroušek, P.
Fedoriková, A.
Dudrová, E.
Actis Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032942.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.-y
81.20.Ev
81.40.Np
Opis:
Porosity can be defined in different ways. The most frequently used definition is the total porosity, which is the total volume fraction of empty space in the specimen. The presence of pores strongly affects the fracture mode. Besides the evaluation of geometry and quality of connections, fractographic analysis enables a quantification of the important microstructural characteristics of the plane porosity. This quantity allows to quantify the existing relations between microstructure and properties. The fractographic evaluation of the distribution of microdeformation processes in the volume of experimental material demonstrates the influence of porosity on the concentration of deformation flows into the microvolume of connections. Plain porosity contributes to the recognition of critical microstructural defects and therefore, to enable evaluating the relationship between the processing parameters, microstructural constituents, and pores. In the fractography evaluation, the analysis of the quality of interparticle bonding using determination of elementary types of fracture facets allows to interpret the mechanical and plastic properties of investigated materials.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1367-1370
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formability Evaluation of Aluminium Alloys by FLD Diagrams
Autorzy:
Petroušek, P.
Kočiško, R.
Kvačkaj, T.
Bidulský, R.
Bidulská, J.
Fedoriková, A.
Sabol, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032922.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Hy
62.10.+s
62.20.M-
81.05.-t
82.80.-d
Opis:
The goal of the present work is evaluated mechanical properties and forming limit diagrams of ambient rolled aluminium alloy based on AlMgSi. Forming limit diagrams are convenient and often used as a tool for the classification of the formability and the evaluation of the forming process of sheet materials. Forming limits of sheet metal are represented in the forming limit diagrams occurring by various deformation states. The most widely used type is the Keeler-Goodwin diagram. Input data got from static tensile test are important for formability evaluating of the thin sheet by mathematical simulations, such as tensile strength, yield strength, elongation, and the strain hardening exponent. The result is a consideration of the suitability of the material for stamping technology.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1344-1346
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
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:
Investigation of the Ultrafine-Grained Structure Formation Under Different Strain Rates
Autorzy:
Kováčová, A.
Kvačkaj, T.
Bidulský, R.
Bidulská, J.
Kočiško, R.
Dutkiewicz, J.
Lityńska-Dobrzyńska, L.
Powiązania:
https://bibliotekanauki.pl/articles/353994.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electron microscopy
EBSD
nanostructured materials
equal channel angular processing
grain refinement
Opis:
The present paper deals with a study on formation of specific substructural features in OFHC copper processed by equalchannel angular pressing (ECAP) considering different strain rate conditions. Since two mechanical tensile testing equipments were being used, strain rate response could be studied in a wide range (both in static and dynamic regimes). Moreover, the copper before tensile testing was subjected to drawing and ECAP, separately, which allows to study the influence of both structural and substructural features (CG vs. UFG structure). Considering the static regime, it was found that UFG materials have advanced properties, showing higher strength and ductility in comparison to their CG counterparts. However, this is valid only to the critical value of the strain rate. In the dynamic regime, mathematical linearized results imply that ultimate tensile strength in samples processed by ECAP increases twice every 10 s-1 rising, however, they lost approximately the same plastic properties than samples after drawing. Differences in the progress of mechanical properties are related to specific structural and substructural features evolved in the material during ECAP processing. Above mentioned features were studied in detail by methods of transmission and scanning electron microscopy (TEM, SEM).
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 851-856
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interparticle Neck Connections in Innovative Insulated Iron Powder Compounds
Autorzy:
Bidulský, R.
Bidulská, J.
de Oro, R.
Hryha, E.
Maccarini, M.
Forno, I.
Actis Grande, M.
Powiązania:
https://bibliotekanauki.pl/articles/1402111.pdf
Data publikacji:
2015-10
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 interparticle neck connections in a system made of insulated iron powder compounds with different additions of an Al-Mg-Si-Cu alloy (0.25, 0.5 and 0.75 wt%). The introduction of the aluminium alloy powder has been made in order to improve the mechanical properties, evaluated as the transverse rupture strength, without decreasing the magnetic properties (evaluated in terms of iron loss and coercivity force). The fracture analysis of investigated systems puts into evidence the breaking of interparticle neck connections. Heat treatment (at the temperature of 500°C) contributes to the early stages of interparticle neck developments. The chosen aluminium alloy presents a sort of pre-sintering behaviour at 500°C, with the possibility of mass-transport processes around the insulated iron powder compounds. The air heat treatment applied aims at providing an increase in the mechanical behaviour of the material, with a final good rigidity after the cooling process. Fracture surfaces and transverse rupture strength values show that, at 500 MPa, the strength and the area related to the inter-particle necks can be correlated to the occasional broken insulated point-to-point surfaces that hinder the development of inter-particles necks.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 647-650
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
Tytuł:
Application of workability test to SPD processing
Zastosowanie testu obrabialności do intensywnego odkształcenia plastycznego
Autorzy:
Kvačkaj, T.
Kočiško, R.
Tiža, J
Bidulská, J.
Kováčová, A
Bidulský, R
Bascó, J
Vlado, M.
Powiązania:
https://bibliotekanauki.pl/articles/351817.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compression test
powder metallurgy
fracture criteria
ECAR
Deform 3D
próba ściskania
metalurgia proszków
kryteria pękania
Opis:
The aluminium alloy with chemical conception AlMgSi prepared by PM (powder metallurgy) technology was used. The experiments such as a ring and compression test, ECAR (equal channel angular rolling) for determination of friction coefficient, stress-strain curves and material workability based on analytical methods (Freudenthal, Cockcroft-Latham and normalized Cockcroft-Latham criteria) were performed. Numerical simulations of sample processed by ECAR was carried out by a software Deform 3D with focus on the description of stress, strain fields and workability criteria (Cockcroft-Latham and normalized Cockcroft-Latham). The prediction of fracture formations in a real ECAR sample during processing conditions was also done.
Stop aluminium o składzie chemicznym AlMgSi przygotowano metodą proszkową. Wykonano badania takie jak próba ściskania swobodnego pierścieni i walcowatych, ECAR (wyciskanie w kanale kątowym z walcowaniem) w celu wyznaczenia współczynnika tarcia, krzywych naprężenie-odkształcenie oraz podatności materiału na odkształcenie z użyciem metod analitycznych (kryterium Freudenthal, Cockcroft-Latham i znormalizowane Cockcroft-Latham). Symulacje numeryczne dla próbki poddawanej procesowi ECAR przeprowadzono przy pomocy oprogramowania Deform 3D z naciskiem na opis pól sił i naprężeń oraz kryteriów obrabialności (Cockcroft-Latham i znormalizowane Cockcroft-Latham). Przeprowadzono również symulacje mozliwości tworzenia się pęknięć w rzeczywistej próbce poddanej procesowi ECAR.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 2; 407-412
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Annealing Conditions on Structural Development of Cryo Rolled FeSi Steel
Autorzy:
Kvackaj, T.
Bidulska, J.
Bidulsky, R.
Kovacova, A.
Kocisko, R.
Bella, P.
Luptak, M.
Bacso, J.
Powiązania:
https://bibliotekanauki.pl/articles/1367991.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Bb
81.05.Bx
81.40.Rs
81.40.Ef
Opis:
Non grain oriented isotropic electrical steels, commercially called NGOES, were investigated in cryogenic temperature conditions. At cryogenic temperatures plastic deformations form strong structural heterogeneities in the sample thickness. Samples processed by cryo rolling show a bigger storage energy. To achieve abnormal grain growth through the process of static recrystallization, the annealing conditions were applied to the deformed samples. Moreover, minimal magnetic losses were reached when mean grain size diameter was approximately 150 μm.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 184-185
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical and Structural Properties of High Purity Al Processed by ECAP
Autorzy:
Kvačkaj, T.
Kočiško, R.
Pokorný, I.
Bidulská, J.
Kvačkaj, M.
Kováčová, A.
Bidulský, R.
Lityńska-Dobrzyńska, L.
Dutkiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/1418957.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.07.-b
81.20.Hy
81.40.-z
Opis:
The mechanical properties and substructure formation of high purity aluminium (99.999%) processed by severe plastic deformation method (equal channel angular pressing) were studied. The equal channel angular pressing process was carried out at room temperature by route C (sample rotation around the axis about 180° after each pass) in a die with two channels intersecting at an angle of Φp = 90. The softening mechanism through dynamic recovery was recognized up to 6th equal channel angular pressing pass, however, after that the mechanical strengthening was revealed. The samples after equal channel angular pressing processing were annealed in different temperature and time conditions. The influence of annealing temperature and time on microhardness as well as diameter of grain size were investigated in samples processed by the 4th equal channel angular pressing pass.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 557-560
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Cryo-Rolling and Annealing on Magnetic Properties in Non-Oriented Electrical Steel
Autorzy:
Kvačkaj, T.
Bella, P.
Bidulský, R.
Kočiško, R.
Petroušek, P.
Fedoriková, A.
Bidulská, J.
Jandačka, P.
Lupták, M.
Černík, M.
Pernis, R.
Powiązania:
https://bibliotekanauki.pl/articles/1032280.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Bb
81.05.Bx
81.40.Rs
81.40.Ef
Opis:
The goal of the present work is to compare progressive technology - rolling at cryogenic temperature and classical rolling at ambient temperature followed by an investigation of their impact on the final microstructure and the magnetic properties of non-oriented electrical steel. Non-oriented electrical steel is characterized by high magnetic induction, low magnetic losses, and low coercivity. The best magnetic properties are achieved using preferable texture and optimal grain size. In this paper there is analyzed the percentage of different textural components after cryo-rolling and after rolling at ambient temperature. To obtain maps of inverse pole figures, the electron backscatter diffraction method was used. The main contribution of this study was that the samples rolled at cryo conditions and after final annealing reached better magnetic properties than at ambient temperature, which was reflected by low magnetic losses and coercivity.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1105-1107
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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