Wyniki wyszukiwania - Biblioteka Nauki

1

Nowoczesne metody badania proszków metali nieżelaznych.

100%

Modzelewska G.

|

1999

|

tom R. 44, nr 6

302-308

PL

Omówiono zasadę działania aparatów pomiarowych nowej generacji znajdujących się w Instytucie Metali Nieżelaznych w Gliwicach przeznaczonych do badania gęstości, powierzchni właściwej i rozkładu ziarnowego proszków.

EN

The principles of activity of new generation measuring apparatures being in Non-Ferrous Metals Institute in Gliwice, predestined for the study of density, specific surface and grain distribution of powders are being treated.

2

Rozwój badań nad materiałami na styki elektryczne

100%

Missol W.

|

2006

|

tom R. 51, nr 12

731-735

PL

Rozwój materiałów stykowych został omówiony w następujących grupach tematycznych: 1 — nowe dodatki do podstawowych ich składników — srebra i miedzi, a mianowicie a— Cr2N do Ag; b — In do Ag-SnO2 ; c — Fe do Ag; d — Cr do Cu, 2 — chemiczne powlekanie srebrem cząstek SnO2, 3 — wysokoenergetyczne mielenie srebra i dodatków, będących nośnikami niemetalicznych składników materiałów stykowych (układy Ag-SnO2, Ag2O-Ag3Sn, Ag-C), 4 — wytwarzanie nakładek stykowych zespolonych z warstwą lutowia.

EN

Not long ago the composite Ag-CdO was the most widely used material for electrical contacts. But it turned out that at people employed at manufacturing and exploitation of the contacts are exposed to inhalation of harmful, toxic cadmium. This is the reason of introducing in Europe other nonmetallic additivies replacing CdO. In accordance with Japanese experience the greatest interest is paid to SnO2 as the substitute. Unfortunately the Ag-SnO2 material requires further investigation with regard to improvement of the plastic and switching properties (endurance behaviour). One way of attaining these aims is using In2O3 as an additional admixture, the second one relies upon chemical coating of tiny SnO2 particles with silver, the third — is mechanical alloying of silver with SnO2 by high-energy ball milling in attritors and disc mills at high rotary speeds. Such kind milling of Ag-C materials gives entirely different results in comparison to Ag-oxide composites leading to lower welding forces but greater erosion rates, due to very fine grained graphite particles (approximately 1 µ). Replacement of nickel by iron in Ag-Ni and tungsten by chromium in the copper-based material is another trend in the electrical contact materials. In the last case together with the economic bonus (cheaper admixture) the killing of the electric arc in vacuum breakers, due to Cr easy volatility, is of significance. As the next topic development of contact tips with permanently connected brazing layers has been discussed.

3

Structure and magnetic properties of hot pressed powder Co77Si11.5B11.5 alloy

100%

Konieczny J. , Wnuk I. , Dobrzański L.

|

2008

|

tom Vol. 31, nr 2

335-340

EN

Purpose: The aim of the work is to investigate the structure and magnetic properties of the cobalt based hot pressed Co77Si11.5B11.5 powder obtained in high-energy ball milling process. Design/methodology/approach: The nanocrystalline ferromagnetic powders were manufactured by highenergy ball milling (SPEX 8000 mill) of metallic glasses ribbons in as state. The hot pressing process was made on machine ''Degussa''. Observations of the structure of die stampings were made on the OPTON DSM-940 and ZEISS SUPRA 35 scanning electron microscope. Tests of magnetic properties were carried out by the use of Lake Shore's Vibrating Sample Magnetometer VSM model 7307. Findings: The analysis of the results enabled determination of the hot pressing parameters on magnetic properties and structure of obtained stampings. Research limitations/implications: For the metallic Co-based amorphous ribbons, further mechanical and structure examinations are planed. Practical implications: Structure and magnetic properties analysis of die stampings of powdered amorphous metallic ribbons is helpful to prepare this material by laboratory methods. Feature an alternative to commercial alloys and composite materials are the amorphous and nanocrystalline metal amorphous ribbons obtained by melt spinning technique and make it possible to obtain the new composite materials with best magnetic properties, which dimensions and shape can be freely formed. Originality/value: The paper presents influence of hot pressing parameters process of metallic powdered ribbons Co77Si11.5B11.5 on structure and magnetic properties of obtained die stampings.

4

Computer aided determination of porosity in sintered steels

100%

Dobrzański L. , Musztyfaga M. , Actis Grande M. , Rosso M.

|

2009

|

tom Vol. 38, nr 2

103-111

EN

Purpose: Purpose of this paper was to apply a computer method of open porosity analysis for determination of porosity in sintered Astaloy CrL and CrM powders. Design/methodology/approach: The powders used in the present papier are pre-alloyed iron-base powders containing low amounts of chromium and molybdenum. The amount of graphite which is mixed with the iron-base powder is 0.6% and lubricant is 0.75%. Green compacts were sintered in a vacuum furnace at 1120°C for 30 minutes in vacuum and rapidly cooled in nitrogen at four different rates: high cooling (7°C/s and 6.5 °C/s) and medium cooling (1.6°C/s) low cooling (0.3 °C/s). Next the samples were tempered in vacuum in the same furnace at 200°C for 60 minutes and cooled in nitrogen, with the exception of low cooling. Obtained samples were examined by light optical microscopy (LOM) for microstructure observation and scanning electron microscopy (SEM). Findings: The investigations of porosity in the pre-alloyed steels were performed using ”Image-Pro Plus 4.5” computer program. Leica light microscope (MEFA4) was applied to prepare series of micrographs. The microstructures were observed at 100x magnification and recorded as*jpg files. After calibration of the digital images, the perimeter, area, diameter, roundness, Feret max were calculated. Practical implications: The program has some limitations (built in mathematical functions), which made difficult to obtain some results automatically. Originality/value: The obtained results prove that this program is very useful in the statistical analysis of microstructures, because it saves the time during calculations and is well suited for checking sintered materials.

5

Klasyfikacja, przykłady i metody wytwarzania materiałów kompozytowych - przegląd literatury.

100%

Madej M. , Sułowski M. , Leżański J.

|

2003

|

tom R. 48, nr 3

134-142

PL

Przedstawiono literaturowy przegląd wiedzy z dziedziny kompozytów. Zaprezentowano klasyfikację oraz charakterystykę kompozytów umacnianych cząstkami, włóknami oraz kompozytów strukturalnych. Przedstawiono czynniki strukturalne oraz związane z metodą wytwarzania wpływające na końcowe własności kompozytów. Zamieszczono także niektóre metody wytwarzania półwyrobów oraz gotowych elementów wykonywanych z materiałów kompozytowych.

EN

Literature review of the state-of-art in the field of composite materials has been made. Classification and characterization of the composites strengthened with particles or fibres and of the structural composites is presented. The structural factors and those related to fabrication methods, influencing final properties of the composites, are discussed. Moreover, some methods for the production of semi-products and final products from the composite materials have been described.

6

Metalurgia proszków

100%

Stolarz S.

|

2005

|

tom R. 50, nr 9

500-501

PL

W artykule omówiono rozwój metalurgii proszków od 1939 r. do czasów obecnych. Zaprezentowano metody wytwarzania spiekanych wyrobów w nowej dziedzinie techniki.

EN

The paper describes progress in the field of powder metallurgy beginning from 1939 till now. The methods for fabricating sintered products by the new techniques have been presented.

7

Discrete element simulation of powder sintering

100%

Rojek J. , Pietrzak K. , Chmielewski M. , Kaliński D. , Nosewicz S.

|

2011

|

tom Vol. 11, No. 1

68-73

EN

This paper presents numerical modelling of powder sintering. The numerical model introduced in this work employs the discrete element method which assumes that material can be modelled by a large assembly of discrete elements (particles) of spherical shape interacting among one another. Modelling of sintering requires introduction of the cohesive interaction among particles representing inter-particle sintering forces. Numerical studies of sintering have been supplemented with experimental studies which provided data for calibration and validation of the model. In the laboratory tests evolution of microstructure and density during sintering have been studied. Comparison of numerical and experimental results shows a good performance of the numerical model developed.

PL

W artykule przedstawiono badania doświadczalne oraz mo-delowanie numeryczne procesu spiekania proszków metalicz-nych. W części eksperymentalnej pracy badano ewolucję mikro-struktury oraz gęstości spieku w trakcie procesu spiekania. Jako metodę modelowania wybrano metodę elementów dyskretnych, w której zakłada się, że materiał jest reprezentowany przez liczny zbiór elementów dyskretnych (cząstek) o kształcie sferycznym oddziałujących między sobą. Modelowanie spiekania wymaga wprowadzenia oddziaływania kohezyjnego między cząstkami reprezentującego naprężenia powstające między ziarnami w trakcie spiekania. W artykule przedstawiono wstępne wyniki numeryczne pokazujące ewolucję gęstości pozornej w trakcie spiekania.

8

Influence of binder composition on structure and properties of carbide alloyed composite manufactured with the PIM method

100%

Matula G.

|

2008

|

tom Vol. 30, nr 2

193-196

EN

Purpose: Influence of binder composition, debinding and sintering conditions on structure and some selected properties of the M2 type injected high speed-steel with 10% of carbides are demonstrated in the paper. Design/methodology/approach: Torque-load test, rheological tests, microstructure examination, density examination. Findings: Examination of the effect of the binder type and portion on structure and properties of the experimental tool materials with the cermets structure revealed that using the stearic acid not only reduces viscosity, thus improving technological properties of the feedstock, but also extend range of the optimum sintering temperature of the investigated cermets ensuring high density and homogeneous structure. Increasing of sintering temperature increase the density of sintering samples. Practical implications: It is expected that further investigations of these materials will make possible their injection moulding, as well as their heat treatment increasing hardness and strength of matrix and thereby of the whole tool material. The Powder Injection Moulding gives the possibility to manufacturing tools materials on the basis of high speed-steel which characterised very good properties with their final or near net shape. Originality/value: In the paper the using injection of the polymer-powder mix gives the possibility to fabricate carbide alloyed composite which, with their structure and mechanical properties, fill the gap in tool materials between the high-speed steels and cemented carbides.

9

Structure and properties of Fe-Co-Ni-B-Si-Nb alloy prepared by mechanical alloying method

100%

Pilarczyk A. , Pilarczyk W. , Nowosielski R.

|

2008

|

tom Vol. 30, nr 2

141-146

EN

Purpose: The goal of this work is to investigate structure and properties of Fe57.6Co7.2Ni7.2B19.2Si4.8Nb4 powders alloys obtained by mechanical alloying. Design/methodology/approach: The test material was the mixture of Fe, Co, Ni, B, Si and Nb powders obtained by the mixing in suitable weight relation. The powders were ground for the 10 and 100 hrs in a high energy planetary ball mill. The microscopic observation of the shape and size of the powdered material particles was carried out by the scanning electron microscope with the magnification 500 times. The changes of the powder structure were tested by means of the X-ray diffractometer. Powder samples by energy dispersion spectroscopy were analyzed too. The measurements of particles size by means of the laser analyser were carried out. Findings: The present paper is the attempt at proposing the mechanical alloying method to obtain multicomponent, Fe-based nanocrystalline alloys. Research limitations/implications: The experiments in this article are made on a laboratory scale. Practical implications: The examined alloys belong to a modern group of soft magnetic materials, which can be used as transformers, sensors, power and electronics devices, etc. Originality/value: In addition a good structural homogeneity and first of all mechanical properties was achieved, also practical application will be possible.

10

Stan obecny metalurgii proszków i perspektywy rozwoju zapotrzebowania rynku na części wykonane z materiałów proszkowych

100%

Wiśniewska-Weinert H. , Plewiński A.

|

1998

|

tom T. 9, nr 1

5-14

PL

Przedstawiono analizę stanu obecnego metalurgii proszków na kontynentach amerykańskich i w niektórych krajach Europy. Szczegółowo przeanalizowano rynek polski i określono przewidywane potrzeby krajowe. Porównano wskaźniki techniczno-ekonomiczne charakteryzujace produkcję jednej tony wyrobów produkowanych tradycyjną technologią obróbki skrawaniem i metodą zagęszczania i spiekania proszków metali. Rozważono problemy polskich zakładów produkujących części z materiałów proszkowych, które dla osiągnięcia poziomu produkcji Europy Zachodniej wymagają nakładów inwestycyjnych.

EN

The paper presents the state of powder metallurgy as it is today in Americans and in some European countries. The Polish market has been analysed in detail and expected domestic demand has been determined. Technical-economical data characterizing the manufacture of a ton of products made by the traditional method of machining have been compared to those characterizing production by compacting and sintering metal powders. Problems of Polish enterprises manufacturing metal powder parts, who need investiments to achieve the West European production level, have been considered.

11

Wpływ lokalnej mikroatmosfery na strukturę i własności spiekanych stali chromowych

100%

Dudek P. , Sułowski M.

|

2008

|

tom R. 53, nr 12

800-803

PL

W artykule przedstawiono badania dotyczące wpływu lokalnej atmosfery na strukturę i własności spiekanych stali chromowych. Badania prowadzono na spiekach wytworzonych z rozpylanego wodą proszku Astaloy CrM firmy Hoganas z dodatkiem 0,5 % mas. węgla w postaci proszku C-UF. Materiały do badań wytworzono na drodze jednokrotnego prasowania i spiekania, które następnie poddano odpuszczaniu na powietrzu w temperaturze 200 stopni Celsjusza. W procesie spiekania w atmosferze azotu do zamkniętych łódek wprowadzano reduktory w postaci kostek żelazomanganu i/lub węgla drzewnego.

EN

In this paper the effect of local microatmosphere on the structure and mechanical properties of PM chromium steels had been discussed. The experiments were carried out on water atomization powder Astaloy CrM with addition 0.5 % carbon C-UF, produced during single pressing and sintering cycle, which were 60 minutes tempered at 200 degrees of Celsius in air. Sintering process was carried out in the atmosphere of pure nitrogen with addition to semi-closed container ferromanganese or/and wood coal.

12

A production attempt of Ni50Ti50 and Ni52Ti41Nb7 alloys by mechanical alloying method

100%

Pilarczyk W. , Nowosielski R. , Pilarczyk A. , Sakiewicz P.

|

2011

|

tom Vol. 47, nr 1

19-26

EN

Purpose: The main aims of this work are the production attempt of Ni50Ti50 and Ni52Ti41Nb7 powder alloys by mechanical alloying method, the presentation of the influence of mechanical alloying time on the structure of obtained alloys and the finding of thermal effects during the heating to temperature of 700şC. Design/methodology/approach: The test material was the mixture of pure nickel, titanium and niobium powders. The powders were ground for the 5, 25 and 40 hrs. The mechanical alloying process was conducted in a high energy SPEX mill under inert argon atmosphere. The microscopic observation of the shape and size of the powdered material particles was carried out by the scanning electron microscope. The changes of the powder structure were tested by means of the X-ray diffractometer. The thermal properties of the powder alloys were examined by DSC method. Findings: Based on the presented experiment results it is clear that producing of assumption powder alloys by mechanical alloying method is possible, but special attention is needed during the selecting of process parameters. The application of used method gives possibility to produce crystalline and amorphous phase in Ni-Ti and Ni-Ti-Nb powder alloys. Research limitations/implications: The experiments in this work are made only on a laboratory scale. Further investigations should be concentrate on the developing of powder consolidation method and refinement particles during high energy ball milling. Practical implications: Ni-Ti alloys exhibit unique shape-memory effects, good corrosion resistance, high wear resistance, biocompatibility and superplasticity. Ni-Ti intermetallic compounds have been widely used in a different fields: mechanical, electric and biomedical applications, aeronautics and astronautics fields. Originality/value: The Ni-Ti and Ni-Ti-Nb powder alloys produced by mechanical alloying method can be use to produce bulk materials with desirable mechanical, physical and chemical properties.

13

Characteristics of structure and properties of a sintered graded tool materials with cobalt matrix

100%

Dobrzański L. A. , Dołżańska B. , Gołombek K. , Matula G.

|

2011

|

tom Vol. 47, nr 2

69-76

EN

Purpose: The mechanical alloying (MA) method has been chosen to manufacture tool gradient materials with high disproportion of cobalt matrix portion between core and surface layer. Design/methodology/approach: The following research studies have been carried out to elaborate a new group of sintered tool gradient materials, tungsten carbide with cobalt matrix, to elaborate their fabrication technology and to determine their structure and properties: a fabrication technology of mixtures and the formation technology of tungsten carbide gradient materials with cobalt matrix WC-Co was applied and elaborated; sintering conditions were selected experimentally, ensuring the best structure and properties; phase and chemical composition of the sintered gradient WC-Co materials was determined using EDX; the structure of sintered gradient WC-Co materials was investigated using scanning microscopy; mechanical and physical properties of sintered gradient WC-Co materials was determined: hardness, resistance to abrasive wear, resistance to brittle cracking. Findings: The presented research results confirm that the methods of mixing tungsten carbide in cobalt matrix an important effect upon the grain size of mixture. But it is not possible to determine the changes in grain size distribution. The larger particles break down rapidly that the product becomes more uniform. Practical implications: The material presented in this paper is characterized by very high hardness of the surface and relative ductility of the core. Originality/value: The obtained results show the possibility to manufacture TGMs on the basis of different portions of cobalt reinforced with hard ceramics particles in order to improve the abrasive resistance and ductility of tool cutting materials.

14

Synthesis and Characterization of Functionally Graded Al-6Cr-Y2O3 Composites

88%

Satish Kumar T. , Krishna Kumar K. , Shalini S. , Subramanian R.

|

15

Modification of Cr-Mo low alloyed steels by addition of Mn via mechanical milling

88%

Sicre-Artalejo J. , Campos M. , Torralba J. M.

|

2008

|

tom Vol. 28, nr 2

199-202

EN

Purpose: The PM industry is in continuous development due to the necessity to increase its potential and competitiveness. This fact and the demand for substituting certain alloying elements used so far, require the addition of new alloying elements and new processes leading to and optimization of costs, strength and tolerances. A different method for introducing Mn into the alloying system is proposed in the present work. Mechanically-blending and mechanically alloying Mn containing master alloys are generated and based on three different steels grades, ASC100.29 (plain iron), Astaloy CrL and Astaloy Mo (pre-alloyed systems). Design/methodology/approach: To profit Mn sublimation effects, small Mn particles, in order to increase the specific surface available to sublimate, must be homogenously added. Different milling times are considered in order to attain the desired master alloys containing 50% of Mn which is diluted in each base powder by normal mixing. New alloying systems were then pressed to a green density of 7.1 g/cm3 and sintered at 1120 ° C in 90N2-10H2 atmosphere. STA showed Mn diffusion during sintering and a densification enhancement. Findings: The sublimation of Mn during sintering provides some specific phenomena which facilitate the sintering of alloying elements with high oxygen affinity. The resulting mechanical properties and the microstructures must be discussed considering the high energy stored in the master alloy which favours the mass transport mechanism during sintering. Research limitations/implications: Research is being continued with the optimisation of the mechanical properties and the application of heat treatments taking the profit of the increase of the hardenability induced by Mn. Originality/value: Mn seems a viable substitute for alloy elements used so far in PM, such as Ni and Mo. Following European regulations Ni cannot be used in its elemental powder form because of its effects on health and Mo has increased its price in the last years.

16

Mechanical and physical properties of sintered aluminum powders

88%

Findik F. , Gökçe A.

|

2008

|

tom Vol. 30, nr 2

157-164

EN

Purpose: The purpose of the work is to compare the physical and mechanical properties for argon atomized Al-1wt-%Mg powders with and without lubricant 1wt% Acrawac. Pure nitrogen sintering was performed and the effect of sintering atmosphere for the mixed Al-1%Mg powder compacts was investigated. Design/methodology/approach: One weight percent Acrawax was premixed with the powder as a lubricant for the first group samples. However, no wax was used for the second group specimens. As a sintering aid, 1wt% Mg was added for both group materials. Compaction of the specimens was performed using a hand operated Carver hydraulic press and a floating rectangular die. First group specimens were pressed to green densities of 91.5 and 92.5% using pressures of 435 and 490 MPa, respectively. In the second group (no wax) samples, 93% green density was obtained using the similar compaction pressures. Sintering and delubrication occurred in a horizontal tube furnace with a high purity nitrogen atmosphere. The nitrogen flow rate was : 1.5 l min⁻¹. The heating rate from the dewaxing to sintering temperature was 10°C min⁻¹. While the sintering temperature kept at 640°C, sintering time varied between at 2 h and 6 h. Three point bending samples were examined using Instron machine using 25.4 span between the lower supports and 2 mm/min strain rate. Findings: Green and theoretical density increased with the increment of compaction pressure. Although Acrawax lubricant provides a reasonable green density, it had a deleterios effect on sintered density mainly owing to its wide burn off range and hence incomplete removal during sintering leaving some black residue. Research limitations/implications: Residual macro- and microporosity was present in all sintered samples under every sintering condition. Medium sized pores and small interconnected micro-pores at grain boundaries were visible when lubricant was added which reduced the sintered densities due to a wide burn off range leaving residual porosity. Originality/value: Mechanical and physical properties of sintered aluminum powders were evaluated.

17

Characterization of Microstructural and Mechanical Properties after Cold Rolling of an Electro-Sinter-Forged Cu-Sn Alloy

88%

Gobber F. S. , Bidulská J. , Fais A. , Franchini F. , Bidulský R. , Kvačkaj T. , Actis Grande M. , Gobber F. S. , Bidulská J. , Fais A. , Franchini F. , Bidulský R. , Kvačkaj T. , Actis Grande M.

|

nr 2

18

Production and Microstructural Characterization of Nb-Si based in-situ Composite

88%

Garip Y. , Garip Y.

|

nr 2

19

Overview of processing technologies for tungsten-steel composites and FGMs for fusion applications

75%

Matějíček J. , Nevrlá B. , Vilémová M. , Boldyryeva H.

Nukleonika

|

2015

|

tom 60

|

nr 2

267-273

EN

Tungsten is a prime candidate material for the plasma-facing components in future fusion devices, e.g. ITER and DEMO. Because of the harsh and complex loading conditions and the differences in material properties, joining of the tungsten armor to the underlying construction and/or cooling parts is a complicated issue. To alleviate the thermal stresses at the joint, a sharp interface may be replaced by a gradual one with a smoothly varying composition. In this paper, several techniques for the formation of tungsten-steel composites and graded layers are reviewed. These include plasma spraying, laser cladding, hot pressing and spark plasma sintering. Structure, composition and selected thermal and mechanical properties of representative layers produced by each of these techniques are presented. A summary of advantages and disadvantages of the techniques and an assessment of their suitability for the production of plasma-facing components is provided.

20

Research of magnetic properties of hybrid composite elements

75%

Kapelski D. , Jankowski B. , Karbowiak M. , Przybylski M. , Ślusarek B.

|

2012

|

tom R. 88, nr 5a

26-27

EN

Hybrid elements are one of the new solutions offered by powder metallurgy. Elements consisting of powders with different magnetic properties make the question of how measure the magnetic properties of hybrid elements composed of layers of material magnetically hard and magnetically soft and dielectromagnets made from a mixture of these same powders. Hybrid elements were made of magnetically hard Nd-Fe-B melt-spun ribbon powder and soft magnetic iron powder.

PL

Hybrydowe elementy są jednym z nowych rozwiązań jakie oferuje metalurgia proszków. Elementy hybrydowe składają się przynajmniej z dwóch obszarów wykonanych z materiałów o innych właściwościach magnetycznych, wykonanych w jednym procesie technologicznym. Takie elementy pozwolą na redukcje kosztów i czasu produkcji silników elektrycznych. Zagadnieniem poruszanym w referacie jest badanie właściwości magnetycznych magnesów hybrydowych złożonych z warstwy magnetycznie twardej proszku Nd-Fe-B oraz warstwy kompozytu żelaza.