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Overview of conventional technologies using the powders of metals, their alloys and ceramics in Industry 4.0 stage

Dobrzański L. A., Dobrzański L. B., Dobrzańska-Danikiewicz A. D.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 98, nr 2

56--85

EN

Purpose: Among the technologies that play a crucial role in the current stage of development of Industry 4.0 conventional powder engineering technologies are of great importance. Based on a comprehensive literature review, conventional technologies using the powders of metals, their alloys and ceramics are described. Development perspectives of the most widespread among them were indicated. Design/methodology/approach: Extensive literature studies on conventional powder engineering technologies have been carried out. By using knowledge engineering methods, development perspectives of individual technologies were indicated. Findings: In addition to the presentation of conventional sintering technological methods, sintering mechanisms in solid-state and liquid phase sintering which accounts for 90% of the commercial value of sintered products are presented. Originality/value: According to augmented holistic Industry 4.0 model, many materials processing technologies and among them conventional powder engineering technologies play a key role in current industry development. For this reason, these technologies have been characterized in detail on the basis of available literature sources.

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Badanie wybranych właściwości wolframowego stopu ciężkiego 98W-1,4Ni-0,6Fe

Skoczylas Paweł

Inżynieria Powierzchni

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2020

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nr 3-4

22--30

PL

Celem pracy było określenie gęstości spiekanego pręta mierzonej wzdłuż jego osi oraz określenie zależności pomiędzy gęstością próbek pobranych z pręta a ich wytrzymałością na rozciąganie Rm. Pręt do badań o składzie 98W-1,4Ni-0,6Fe wytworzono metodą metalurgii proszków i spiekania z udziałem fazy ciekłej. Przeprowadzone pomiary wykazały, iż gęstość próbek jest zależna od miejsca pobrania próbki z pręta oraz ilości usuniętej warstwy zewnętrznej poprzez toczenie. Gęstości próbek pobranych z końców pręta są wyższe niż ze środka pręta. Najniższą gęstość uzyskano dla gotowych próbek wytrzymałościowych. Przeprowadzone pomiary wykazały, że dla kilku próbek wyniki gęstości i wytrzymałość Rm są ze sobą skorelowane. Stopniowo obniżająca się gęstość próbek przekłada się na spadek ich wytrzymałości na rozciąganie. Niższa gęstość próbek z obszaru środkowej części pręta może być związana zarówno ze skurczem liniowym występującym w trakcie procesu, jak również z nierównomiernym rozkładem temperatury w przestrzeni pieca do spiekania.

EN

The aim of the work was to determine the density and tensile strength Rm of the sintered rod measured in selected places along its axis. The test rod with the composition of 98W-1.4Ni-0.6Fe was produced by powder metallurgy and sintering with the participation of the liquid phase. The performed measurements showed that the density of the samples depends on the place where the sample was taken from the bar and the amount of the outer layer removed by rolling. The densities of samples taken from the ends of the bar are higher than those taken from the center of the bar. The lowest density was obtained for ready-made strength samples. The performed measurements showed that for several samples the results of density and strength Rm are correlated. Gradually decreasing sample density translates into a decrease in their tensile strength. The lower density of samples from the central part of the bar can be related both to the linear shrinkage occurring during the process, as well as to the non-uniform temperature distribution in the sintering furnace space.

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Research into the Production of Tungsten Heavy Alloys with Specific Mechanical Properties

Skoczylas Paweł, Gulbinowicz Zbigniew, Goroch Olgierd, Barcz Katarzyna, Kaczorowski Mieczysław

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2019

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Vol. 10, Nr 4 (38)

23--36

EN

The subject of the work discussed herein and carried out as a part of the Polish National Centre of Research and Development project titled ”Development and implementation of critical technology demonstrators for the new generation of 120 mm tank artillery ammunition” are the results of a research into the influence of LPS (Liquid Phase Sintering) parameters and heat treatment on the mechanical properties of W91Ni6Co3 and W91Ni6Co2.25Fe0.75 alloys, designated PR200 and PR201, respectively. The alloys, as LPS-processed and heat treated, were tested on a strength testing machine to determine their tensile strength (Rm), proof stress (Rp0.2) and elongation (A5). The analysis of the test results resulted in a proposal of manufacturing process parameters to have the alloys tested develop specified mechanical properties. It was found the ternary alloy with chemical composition W91Ni6Co3 and designated PR200 was more promising in the feasibility of producing specified mechanical properties. The alloy, once sintered and heat treated in two stages, could facilitate production of a material with a tensile strength Rm>1400 MPa, a yield strength Rp0.2 > 1350 MPa, a minimum elongation of 11%, and an impact strength > 115 J/cm2.

PL

Przedmiotem niniejszego pracy, zrealizowanej w ramach projektu NCBiR i zatytułowanego "Opracowanie i wykonanie demonstratorów technologii krytycznych elementów do nowej generacji amunicji czołgowej 120mm" są wyniki badań wpływu parametrów spiekania z udziałem fazy ciekłej - LPS (ang. Liquid Phase Sintering) oraz obróbki cieplnej na właściwości mechaniczne stopów W91Ni6Co3 oraz W91Ni6Co2,25Fe0,75 oznaczonych odpowiednio symbolami PR200 oraz PR201. Wytypowane stopy, po spiekaniu oraz obróbce cieplnej, były badane na maszynie wytrzymałościowej celem wyznaczenia wytrzymałości na rozciąganie (Rm), umownej granicy plastyczności (Rp0,2) oraz wydłużenia (A5). Na podstawie analizy wyników badań zaproponowano parametry procesu wytwarzania umożliwiające uzyskanie przez badane stopy wymaganych właściwości mechanicznych. Stwierdzono, iż z punktu widzenia tych właściwości, bardziej perspektywiczny jest trójskładnikowy stop o składzie chemicznym W91Ni6Co3 oznaczony symbolem PR200. Stop ten, po spiekaniu i dwustopniowej obrce cieplnej umożliwia uzyskanie materiału o wytrzymałości na rozciąganie Rm>1400 MPa, umownej granicy plastyczności Rp0,2 powyżej 1350 MPa, wydłużeniu minimum 11% oraz udarności KC>115 J/cm2

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Densification and Mechanical Properties of 439L Steel Composites Blended with Fifteen Micron-Size Silicon Carbide Particles

Lee Sang Woo, Shin Hyunho, Rhee Kyong-Yop

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

883--888

EN

439L stainless steel composites blended with fifteen micron SiC particles were prepared by uniaxial pressing of raw powders at 100 MPa and conventional sintering at 1350°C for 2 h. Based on the results of X-ray diffraction analysis, dissolution of SiC particles were apparent. The 5 vol% SiC specimen demonstrated maximal densification (91.5%) among prepared specimens (0-10 vol% SiC); the relative density was higher than the specimens in the literature (80-84%) prepared by a similar process but at a higher forming pressure (700 MPa). The stress-strain curve and yield strength were also maximal at the 5 vol% of SiC, indicating that densification is the most important parameter determining the mechanical property. The added SiC particles in this study did not serve as the reinforcement phase for the 439L steel matrix but as a liquid-phase-sintering agent for facilitating densification, which eventually improved the mechanical property of the sintered product.

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Synthesis, microstructure and mechanical properties of bronze–molybdenum composites processed via LPS and SPS methods

Memari S., Ardestani M., Abbasi A.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1013--1023

EN

In this work, synthesis, densification and properties of bronze–70 wt% Mo and bronze–30 wt% Mo composite powders were investigated. The composite powders were prepared by mechanical milling of bronze–Mo powder mixtures for 16 h. The results of cold compressibility investigations showed that Heckel and Ge equations provided the best fit scenario for bronze–70 wt% Mo and bronze–30 wt% Mo, respectively. The composite powders were consolidated via pressureless and spark plasma sintering processes. The relative densities of spark plasma sintered samples with 30 and 70 wt% molybdenum were about 98%. However, the relative density of bronze–70 wt% Mo and bronze–30 wt% Mo pressureless sintered samples were 97.1 and 94.3%, respectively. The scanning electron microscopy observations revealed that the size and dispersion of Mo particles within the bronze matrix in the pressureless sintered samples was completely different from that of the spark plasma sintered ones. Furthermore, it was found that in spite of nearly close relative densities, the hardness and flexural strength of the spark plasma sintered samples were higher than that of the pressureless sintered ones which was due to different shape, size and dispersion of the Mo particles within the matrix phase in the different samples. According to the results, the preferred densification process was SPS method.

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In-situ syhnthesis of SiC-ZrC-Al2O3-ZrO2 composite

Atasoy A

Archives of Materials Science and Engineering

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2016

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Vol. 78, nr 2

53--58

EN

Purpose: The aim of the study was the processing of SiC based ceramic of SiC-Al2O3-ZrO2 composite with the various of starting composition silicon carbide (from 20% to 60 %), zircon (from 20% to 60%) and aluminum (from 0% to 10%) powders using solid and liquid sintering methods, and the physical properties and the characterization of the newly formed phases ant used experimental parameters. Design/methodology/approach: In order to analyses the reaction mechanism as well as the thermal behavior of the starting compositions, thermal analysis /TG/DTA and for the determination of nay phases, X-ray diffraction methods were used. To examine the morphology and particles morphology and the microstructures, scanning electron microspore (SEM) was used. Findings: The TG/DTA curves show endo/exothermic peaks related with the formation of carbides. The addition of Al was prevented the formation of yttrium aluminates phases. In presence of Al, the reduction and the liquid phase formation takes place. SiC acts as reducing agent. SiC-Al2O3-YSZ-ZrO2 phases were detected but at higher temperature the reaction phases were changed to ZrC, AlYZr, Y2O3 were detected as major phases in the processed samples. Practical implications: After the determination of the obtained phases, the resulting product is ceramic composite which consists of SiC-Al2O3-YSZ-ZrO2, ZrC, AlYZr, Y2O3 phases. It has potentially attractive composite where requires thermal stability in high temperature applications. Originality/value: The addition of aluminum to the mixture was facilitate the sintering process, was lowering the sintering temperature due to the high exothermic reaction which changes the reaction mechanism of the sintering from solid to liquid one.

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Effect Of Compaction Pressure And Sintering Temperature On The Liquid Phase Sintering Behavior Of Al-Cu-Zn Alloy

Lee S. H., Ahn B.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1485--1489

EN

The liquid phase sintering characteristics of Al-Cu-Zn alloy were investigated with respect to various powder metallurgy processing conditions. Powders of each alloying elements were blended to form Al-6Cu-5Zn composition and compacted with pressures of 200, 400, and 600 MPa. The sintering process was performed at various temperatures of 410, 560, and 615°C in N2 gas atmosphere. Density and micro-Vickers hardness measurements were conducted at different processing stages, and transverse rupture strength of sintered materials was examined for each condition, respectively. The microstructure was characterized using optical microscope and scanning electron microscopy. The effect of Zn addition on the liquid phase sintering behavior during P/M process of the Al-Cu-Zn alloy was also discussed in detail.

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Microstructure evolution in warm forged sintered ultrahigh carbon steel

Szczepanik S., Nikiel P., Mitchell S. C., Kawalla R.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 2

301--307

EN

Fe–1.4C–0.65Si–0.85Mo ultrahigh carbon steel was liquid phase sintered in 10%H2–90%N2 at 1300 °C from Höganas Astaloy 85 Mo HP base iron, fine graphite and silicon carbide powders mixed with polypropylene glycol. The microstructure then comprised fine pearlite and grain boundary cementite networks and the density increased from ∼6.8 g cm−3 to ∼7.7 g cm−3. A group of specimens then underwent austenitisation, isothermal quenching/autotempering at M(10%) temperature, followed by cooling to room temperature. This produced a crack-free martensitic microstructure, which transformed to ferrite plus fine spheroidised carbides by annealing for 3 h at 750 °C. To attain full density and well-distributed submicron carbides, these specimens were warm forged at 700–750 °C. To ascertain if some processing steps can be discarded, as-sintered and quenched samples were similarly thermo-mechanically processed. The required stresses and resultant microstructures depended on temperature and strain rate, with optimum microstructure, for Bähr processing at 775 °C of quenched material, fully comparable with that of prior spheroidised specimens. Microstructures and hardness values are presented for all processing routes.

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Microstructures and mechanical properties of a warm processed sintered ultrahigh carbon steel

Mitchell S., Szczepanik S., Nikiel P., Wroński A.

Rudy i Metale Nieżelazne Recykling

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2014

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R. 59, nr 12

605--611

EN

Fe-0.85Mo-0.6Si-1.4C ultrahigh carbon steel was liquid phase sintered to near-full density at 1300 °C, the temperature chosen as a result of generating a Thermo-Calc theoretical phase diagram. Major modifications in the mixing and sintering cycle steps of conventional powder metallurgy processing were required to attain near-full density. The sintered brittle microstructure comprised fine pearlite and grain boundary cementite networks. In order to obtain a strong, ductile spheroidised microstructure, several subseąuent routes were investigated. The conventional heat treatment involved austenitisation, ąuenching and spheroidisation at 750 °C for 3 h, which resulted in a density of ~7.2 g cc-1, grain size of ~30 pm and aferrite plus submicrometre carbide structure. Further densification and microstructural refinement were obtained by subsequent closed die forging. To discover whether the number of processing steps could be reduced, thermomechanical processing on Gleeble and Bahr machines was carried out on as-sintered and quenched specimens. Compression at 750 and 775 °C to ~0.7 natural strain, of assintered material produced a banded structure of pearlite, ferrite and cementite, free of grain boundary carbides. Only processing at 700-775 °C of either quenched or of already spheroidised specimens, how-ever, resulted in full densification and spheroidised structures, finer in the case of the latter treatment. Hardness ranged from 765, quenched state, through 312, sintered, to 205-289 HV10, spheroidised. Mechanical properties of the spheroidised specimens were: yield strengths up to 410 MPa, fracture strengths up to 950 MPa and strains up to 16 %. For a spheroidised and Gleeble 700 °C processed disc tested in diametral compression, the yield stress increased to 769 MPa and the transverse diametral extension was 23 %.

PL

Spiekanie z udziałem fazy ciekłej w temperaturze 1300 °C wysokowęglowej stali Fe-0,85Mo-0,6Si-l,4C prowadzi do uzyskania gęstości zbliżonej do gęstości teoretycznej (stan 1). Krucha mikrostruktura zawiera wtedy drobny perlit z siatką cementytu na granicach ziaren. Dodatkowo próbki austenityzowano i hartowano (stan 2), a następnie sferoidyzowano (stan 3) lub odkształcano na ciepło w temperaturze 700-775 °C (stan 4), lub sferoidyzowano i odkształcano na ciepło (stan 5). Odkształcanie przeprowadzono na symulatorze Gleeble, plastometrze Bahr i prasie kuźniczej. Naprężenia podczas odkształcania z prędkością 0,001 do 1 s'1 zawierały się w przedziale 130-460 MPa. Odkształcanie w temperaturze 700-775 °C, zarówno hartowanych jak i sferoidyzowanych próbek, powoduje pełne dogęszczenie materiału i uzyskanie sferoidalnej mikrostruktury, o drobniejszym ziarnie w poprzednio sferoidyzowanych próbkach. Ściskanie w temperaturze 750 i 775 °C spiekanego materiału powoduje powstanie pasmowej mikrostruktury, bez węglików na granicach ziarn, złożonej z perlitu, ferrytu i cementytu. Twardość próbek zmienia się od wartości 765 dla próbek hartowanych, 312 dla próbek spiekanych do 205+289 HV10 dla mikrostruktury sferoidalnej. Mechaniczne własności dla próbek ze sferoidalną mikrostrukturą są: granica plastyczności — do 410 MPa, wytrzymałość na rozciąganie — do 950 MPa i wydłużenie — do 16 %.

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The influence of Fe content on spreading ability of tungsten heavy alloys matrix on tungsten surface

Kaczorowski M., Skoczylas P., Krzyńska A.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3 spec.

103--106

EN

The results of experimental study of tungsten spreading ability with W-Ni-Co-Fe matrix are presented. The aim of these investigations was to see how Fe concentration in W – Ni – Co matrix influences the wettability of tungsten grains during liquid phase sintering. Four green compact specimens containing 50%W, 10%Co and Ni + Fe = 40% but with different Ni to Fe ratio were prepared. The cylindrical specimen 5mm diameter and 5mm height were put on clean pure tungsten substrate and then 20 minutes heated at 1520ºC in hydrogen atmosphere. After heating the specimens were carefully measured and then the specimens for structure observations were prepared. It was concluded, that increase of Fe content decrease the melting temperature of W – Ni – Co alloy. The melting point decrease caused by Fe content increase substantially the spreading ability of tungsten substrate with W – Ni – Co alloy. Metallography investigations showed some microstructure changes in “reaction zone” identified in tungsten substrate – (WNi40-xCo10Fex) interface. The results of the study confirmed our earlier observations that even relative small Fe addition promotes Weight Heavy Alloys (WHA) liquid phase sintering.