Wyniki 1-9 spośród 9 dla zapytania: authorDesc:"Dariusz Garbiec"

Iskrowe spiekanie plazmowe (SPS): teoria i praktyka DOI:10.15199/28.2015.2.2


  Spark plasma sintering: theory and practise The study discusses the method of Spark Plasma Sintering (SPS). It presents a historical outline of resistance sintering, and the developmental stages of sintering technology using high-current DC pulses. The material presents a schematic illustration of a spark plasma sintering furnace, and describes its construction approach. It also enables the reader to gain some awareness as to the current levels of knowledge found - with regards to the mechanism of sintering using high-current DC pulses - and, the method of spark plasma sintering and possible future developments in this field. The analysis presented in this paper utilizes parameters of the SPS device located at the Metal Forming Institute in Poznan. It describes results of tests carried out on materials which have been sintered at the Metal Forming Institute, since 2011. It has been shown, that it is possible to perform sintering using the SPS method on one or multiphase materials, which the individual components differ in melting point, density and particle size. Key words: spark plasma sintering, Joule’s heat, composite. W pracy omówiono metodę iskrowego spiekania plazmowego. Przedstawiono rys historyczny spiekania rezystancyjnego oraz etapy rozwoju technologii spiekania z wykorzystaniem silnoprądowych impulsów prądu stałego. Zaprezentowano schemat urządzenia do iskrowego spiekania plazmowego oraz opisano jego budowę. Przedstawiono obecny stan wiedzy na temat mechanizmu spiekania z wykorzystaniem silnoprądowych impulsów prądu stałego oraz wskazano zastosowanie metody iskrowego spiekania plazmowego, jak i jej dalszy rozwój. W pracy zaprezentowano parametry urządzenia SPS znajdującego się w Instytucie Obróbki Plastycznej w Poznaniu. Przedstawiono wyniki badań nad materiałami, które spiekano w Instytucie Obróbki Plastycznej od roku 2011. Wykazano, iż metodą SPS jest możliwe spiekanie materiałów jedno- i wielofazowych, których poszczególne[...]

Spiekanie tytanu i hydroksyapatytu metodą iskrowego spiekania plazmowego


  W artykule omówiono metodę iskrowego spiekania plazmowego SPS (ang. Spark Plasma Sintering). Przedstawiono graficznie proces spiekania wraz ze schematem urządzenia oraz wyjaśniono mechanizm spiekania impulsami prądu stałego. Opracowano proces spiekania proszku stopu tytanu Ti6Al4V oraz proszku hydroksyapatytu (HA) wraz z 5 % dodatkiem srebra. Ocenie za pomocą mikroskopu skaningowego poddano powierzchnię uzyskanych próbek. Na podstawie badań zaproponowano parametry wytwarzania próbek przeznaczonych do badań in-vitro. Wykazano, że minimalną temperaturą przy której można uzyskać powłokę HA charakteryzującą się dobrym połączeniem z podłożem jest 750 oC. The article discusses the method of Spark Plasma Sintering. Presented graphically sintering process and SPS device diagram. Explained the mechanism of sintering DC pulses. Titanium alloy powder Ti6Al4V and hydroxyapatite powder with 5 % silver sintering process was developed. Evaluated by scanning electron microscopy were obtained surface samples. Based on the research proposed parameters for sample preparation on in-vitro. It was shown that the minimum temperature at which the HA coating can be characterized by good access to the substrate is 750 °C. Słowa kluczowe: iskrowe spiekanie plazmowe, ciepło Joule’a, stop tytanu Ti6Al4V, hydroksyapatyt Key words: Spark Plasma Sintering, Joule heating, titanium alloy Ti6Al4V, hydroxyapatite.Wprowadzenie. Instytut Obróbki Plastycznej realizuje i koordynuje prace badawcze w ramach projektu w 7. Programie Ramowym Komisji Europejskiej w ramach wspólnego konkursu Komisji Europejskiej UE i Meksykańskiej Organizacji CONACYT "Adding Value to Mining at the Nanostructure level" - "Rozwój i zastosowanie nowych nanokompozytowych materiałów otrzymywanych w recyklingu metali szlachetnych" o akronimie NANOMINING [1]. W ramach projektu wytworzono przy wykorzystaniu metody iskrowego spiekania plazmowego podłoża ze stopu tytanu Ti6Al4V o wymiarach Ø20 × 10 mm (rys. 1[...]

STALE SZYBKOTNĄCE SPIEKANE METODĄ SPS DOI:10.15199/67.2015.8.5


  W artykule przedstawiono wyniki w zakresie badania mikrostruktury spiekanych metodą SPS kompozytów na osnowie stali szybkotnącej gatunku M3/2. Kompozyty na osnowie stali szybkotnącej wytwarzano do tej pory wieloma metodami, jednak metoda iskrowego spiekania plazmowego (Spark Plasma Sintering) stanowi nowatorską metodę ich wytwarzania. Materiał badawczy stanowiły kształtki ze stali szybkotnącej z dodatkiem żelaza i z dodatkiem żelaza i miedzi. Kształtki spiekano metodą SPS z wcześniej przygotowanych mieszanek proszków. Kompozyty poddano badaniom gęstości względnej, twardości, wytrzymałości na zginanie. W pracy przedstawiono także mikrostruktury spiekanych kompozytów. Słowa kluczowe: kompozyty, stal szybkotnąca, żelazo, miedź, spiekanie SPS HIGH SPEED STEELS SINTERED BY SPS METHOD The article presents the results for the investigations of the microstructure and properties of HSS based composites sintered by SPS method. HSS based composites could be produced by a many methods, but the method of spark plasma sintering (Spark Plasma Sintering) is a novel method for their preparation. The powder compositions used to produce composites were: 45%Fe-15%Cu-40%M3/2 and M3/2+50 % Fe. The powders were sintered by SPS method at 950 °C under pressure 50 MPa for 2,5 minutes. The as-sintered composites were tested for density, Brinell hardness and bending strength. From the analysis of the obtained results it has been found that the mechanical properties are mainly affected by the chemical compositions of composites and its porosity. The analysis have shown that the addition of copper reduces the hardness while increasing the bending strength. The study also shows the microstructure of the as-sintered composites. Keywords: composites, high speed steel, iron, copper, SPS sintering Wprowadzenie Nowoczesne metody wytwarzania różnych gatunków stali szybkotnących i kompozytów na osnowie stali szybkotnących oparte są na procesach metalurgii proszków. Kompozyt[...]

ISKROWE SPIEKANIE PLAZMOWE JAKO EFEKTYWNA METODA WYTWARZANIA WYROBÓW Z PROSZKÓW SPIEKANYCH


  W artykule przedstawiono istotę iskrowego spiekania plazmowego oraz schemat urządzenia SPS. Wyjaśniono mechanizm spiekania z wykorzystaniem silnoprądowych impulsów prądu stałego. Przedstawiono wyniki badań nad niektórymi materiałami które spiekano metodą SPS w Instytucie Obróbki Plastycznej w Poznaniu od roku 2011. Wykazano, iż metodą SPS możliwe jest spiekanie materiałów jedno jak i wielofazowych oraz napiekanie powłok na wcześniej wytworzone spieki. Przedstawiono prognozę co do przyszłych zastosowań metody SPS. Słowa Kluczowe: iskrowe spiekanie plazmowe, stop tytanu, stal narzędziowa, kompozyt SPARK PLASMA SINTERING AS AN EFFECTIVE METHOD FOR THE FORMATION PRODUCTS FROM SINTERED POWDERS This article presents the essence of spark plasma sintering and a diagram of an SPS machine. The mechanism of sintering with the application of high intensity direct current impulses is explained. Since 2011, research work has been conducted at the Metal Forming Institute in Poznan on powder materials consolidated using the spark plasma sintering method. This article presents selected results of studies on the Ti6Al4V alloy, Astaloy CrM tool steel, and an Al-Al2O3 composite material, which were sintered using the SPS method. It was shown that it is possible to sinter both single-phase and multi-phase materials characterized by a density near theoretical density (10% Al-Al2O3 composite material with a relative density of 97 %) and to “sinter on" coats onto previously produced sinters (HAp layer on a titanium substrate) using the spark plasma sintering method. Using the example of sintered Astaloy CrM tool steel, it was shown that the values of density and tensile strength increase as compaction pressure increases. This article also presents a prognosis concerning future applications of the SPS method. Keywords: spark plasma sintering, titanium alloy, tool steel, composite Wstęp [...]

Struktura i właściwości stopu CoCrMo spiekanego metodą SPS DOI:10.15199/24.2015.9.11


  W pracy przedstawiono wyniki badań właściwości mechanicznych oraz analizy struktury spieków z proszku stopu CoCrMo (ASTM 75) wy- tworzonych metodą iskrowego spiekania plazmowego. Spiekanie realizowano w temperaturze 1050ºC z szybkością nagrzewania 100°C/min, przy ciśnieniu prasowania wynoszącym 100 MPa. Czas spiekania wynosił odpowiednio 5, 10 i 15 minut. Na podstawie uzyskanych wyników badań wykazano wpływ czasu spiekania na właściwości mechaniczne spieków. Największą twardością (381 HV0.5) oraz wytrzymałością na rozciąganie (1280 MPa) i na ściskanie (1847 MPa) odznaczają się próbki spiekane w czasie 5 minut. The paper presents results of strength and structural tests of sintered samples made of CoCrMo powder alloy (ASTM F75) and received by spark plasma sintering. The sintering process was carried out at a temperature of 1050ºC, using a heating rate of 100°C/min under compaction pressure of 100 MPa. Samples were sintered at different times - 5, 10 and 15 minutes. On the basis of research results was rated the impact of sintering time on the mechanical properties of obtained sintered samples. The samples sintered in time 5 minutes had the highest hardness (381 HV0.5), tensile strength (1280 MPa) and compressive strength (1847 MPa). Słowa kluczowe: CoCrMo, metalurgia proszków, iskrowe spiekanie plazmowe, właściwości mechaniczne Key words: CoCrMo, powder metallurgy, spark plasma sintering, mechanical properties.Wprowadzenie. Ze względu na biokompatybilność, odporność na zużycie przez tarcie, odporność korozyjną, a także korzystne właściwości mechaniczne, stopy Co są powszechnie stosowane w medycynie m. in. na endoprotezy, stenty, czy implanty stomatologiczne [1÷3]. Od wielu lat prowadzone są liczne prace badawcze mające na celu poprawę właściwości stopów Co, m.in. poprzez doskonalenie obecnie stosowanych technik ich wytwarzania, do których zalicza się odlewanie (precyzyjne, odśrodkowe oraz próżniowo-ciśnieniowe), kucie, a także cor[...]

Wpływ wyciskania metodą KOBO na wytrzymałość zmęczeniową stopu aluminium 7075 DOI:10.15199/28.2015.6.3


  Effect of KOBO extrusion method on the fatigue strength of 7075 aluminum alloy Investigations on the AW-7075 aluminum alloy in the F state, following the KOBO extrusion, supersaturation and aging have been carried out. Results have been presented of the measurements of hardness, tensile tests and fatigue strength tests performed with the classic and Locati accelerated method (stepwise increasing stress by approx. 70 MPa every 30 to 60 thousand cycles). The tensile tests have been performed on conical samples (with a variable diameter of the curve radius of 72 mm). The aim of the investigations was the assessment of the influence of the KOBO method forming of a half-product in the temperature of 400°C subsequently chilled with water at the outlet of the cast on the mechanical properties of the alloy and a comparison with the material not subject to the extrusion. The results obtained in the tensile tests have shown similar elasticity boundary, which was approx. 600 MPa and tensile strength above 650 MPa. The tests have been performed on thermally processed samples to state T6 and following the KOBO extrusion and short-term supersaturation and aging. Similar results were obtained in the measurements with the Brinell method. They were 176 HB for the T6 material and 175 HB for the material following the KOBO extrusion and thermal processing. The results of the fatigue tests carried out at the frequency of 15 Hz, maximum stress of 354 MPa in the pulsating — tensile cycle indicate that the KOBO extrusion process with the subsequent supersaturation and aging improves its fatigue strength. The results obtained with the Locati method indicated similar fatigue strength of all tested materials. The samples in the F state during fatigue tests were loaded with the stress of 425 MPa, which was greater by 45 MPa than the tensile strength determined in the tests. This confirms the deformation strengthening that took place during the dynamic tests. Key w[...]

Effect of TaC&-NbC additive on durability of WC&-Co cutting edges DOI:10.15199/28.2018.4.4


  1. INTRODUCTION Cemented carbides are widely used for cutting edges and various elements of machine parts [1, 2]. Their properties, such as high hardness, good toughness and wear resistance, are due to the combination of hard and brittle tungsten carbide (WC) and a soft and plastic metallic binder, e.g. cobalt (Co) [3]. The choice of cobalt is not accidental because the metal conducts heat very well (100 W/(m·K)), perfectly moistens tungsten carbide (contact angle ~0°) and has a high melting point (1494°C). The content of cobalt in cemented carbides is not constant and ranges from a few - 5÷10 (for cutting tools) to even several tens - 20÷30 (for tools for forming processes) weight percent (wt %) [4, 5]. The durability of cutting edges made of cemented carbides depends on wear mechanisms like flank wear, crater wear, built up edge, notch wear, plastic deformation, thermal cracks, edge chipping [6], and they depend on the microstructure and mechanical properties of the tool material. One of the directions of improvement of the mechanical properties is microstructure evolution, e.g. reducing the size of the WC grains. Research has shown that reducing WC grains below 500 nm has a positive effect on the mechanical properties by increasing hardness and toughness [7]. Moreover, an addition of chromium carbide (Cr3C2) [4, 8, 9], tantalum carbide (TaC) [4, 9÷11], niobium carbide (NbC) [12], vanadium carbide (VC) [8, 11] or titanium carbide (TiC) [10, 12, 13] can effectively increase the mechanical properties. Another method is to use advanced powder metallurgy methods. One of them is pulse plasma sintering (PPS) which belongs to the group of methods of Field Assisted Sintering Technology (FAST) and is presented in greater detail in [14]. Nowadays, by using FAST methods, cemented carbides with improved mechanical properties are produced [4, 7÷10, 13], but the exploitation properties of WC-Co-TaC-NbC[...]

Effect of manufacturing technology of ball-and-socket joint made of Co28Cr6Mo alloy on its tribological properties DOI:10.15199/28.2017.1.5


  The article presents the results of friction and wear testing of ball-and-socket joints, made of ASTM F75 alloy powder, applying the technologies of selective laser melting and spark plasma sintering. The reference material constituted joints produced by machining from a ASTM F1537 LC rod. The tribological tests were carried out using the movement simulator of a spinal motion segment of our own design, in the environment of distilled water. The test results consisted of a comparison of the friction resistance values occurring in the friction couple and comparison of the wear indicators of the upper and lower components, which simulate the tribological system of an intervertebral disc endoprosthesis in the spinal lumbar segment. Analysis of the wear mechanism of the bearing surfaces was performed on the basis of microscopic observations and measurements of friction surface roughness. Regardless of the manufacturing technology, the coefficient of friction varied in the range of 0.25 to 0.30, wherein a median value for all the tested material combinations was in the range of 0.27 to 0.29. The lowest resistance to tribological wear was demonstrated by the joints produced employing spark plasma sintering technology. The wear of the joints produced with this technology was about 20% higher in comparison to those joints formed by selective laser melting, and about 30% higher compared to the joints produced in a conventional manner from ASTM F1537 LC alloy. Observations performed using scanning electron microscopy showed that regardless of the production technology, the dominant type of wear was abrasive-adhesive wear. Unlike the joints produced in a conventional manner, the bearing surfaces of the components produced by means of selective laser melting and spark plasma sintering technologies, there is evidence of fatigue damage. The results call into question the possibility of using alternative technologies in the manufacturing process of endoprosthe[...]

Effect of manufacturing technology on tribological properties of Co28Cr6Mo alloy DOI:10.15199/28.2016.5.7


  The physical, chemical, mechanical properties of alloys used in endoprosthesis components in the osteoarticular system or dental implants depend not only on the chemical composition, but also on the applied production technology. The article presents the results of friction and wear testing of samples produced by selective laser melting and spark plasma sintering of the ASTM F75 alloy powder (Co28Cr6Mo alloy). As reference material, an ASTM F1537 LC rod was used from which samples were prepared by machining. The friction and wear tests were conducted by means of a tribological tester with a block-ring tribosystem. The tests were performed without lubricating fluid at ambient temperature. The test results constituted a comparison of the frictional resistance in contact with bearing steel 100Cr6 as well as a comparison of the wear values depending on the given friction pair load as a function of sliding distance. Analysis of the wear mechanism of the test materials was based on microscopic observation of the friction surfaces, chemical composition analysis of the surfaces using energy dispersive X-ray spectroscopy as well as roughness measurements. For the friction pair involving the reference sample, the friction coefficient was characterized by a constant value of about 0.40 regardless of the load or travelled sliding distance. In the case of the samples greater frictional resistance was found. The friction coefficient for the friction pairs involving samples produced using the technology of selective laser melting and spark plasma sintering varied in the range 0.50 to 0.62 and from 0.70 to 0.74. Based on the obtained results of weight loss, it was calculated that the reference material sample was characterized by the smallest wear coefficient, while the largest was demonstrated by samples produced by spark plasma sintering. Microscopic observations showed that regardless of the employed technology to produce the samples, the dominant type of w[...]

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