Wyniki wyszukiwania - BazTech

1

Deformation behaviour of high-manganese steel with addition of niobium under quasi-static tensile loading

Jabłońska Magdalena Barbara, Jasiak Katarzyna, Kowalczyk Karolina, Bednarczyk Iwona, Skwarski Mateusz, Tkocz Marek, Gronostajski Zbigniew

Materials Science Poland

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2022

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Vol. 40, No. 3

1--11

EN

In this paper, the heat generated during deformation under the static testing of high-manganese TWIP steel with addition of niobium was determined. The research combined the interaction of heat generated during deformation, mechanical properties, hardness and microstructure. Temperature and strain were measured simultaneously using infrared (IR) thermography and digital image correlation (DIC) method. The average temperature measured at the necked region equals 42°C at the strain rate of 0.001 s−1 and exceeds 100°C at 0.5 s−1. Therefore at large strains, a reduction in stress was observed. The course of the hardness change coincides very well with the strain changes, however, at the strain rate of 0.5 s−1 near to the necking area the hardness equals to 360 HV2, whereas at the lower strain rates it equals to 370 HV2. These changes are connected mainly with increase in temperature to >100°C

2

Technological Development of a Yarn Grip System for High-Speed Tensile Testing of High-Performance Fibers

Unger Reimar, Schegner Philipp, Nocke Andreas, Cherif Chokri

Autex Research Journal

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2019

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Vol. 19, no. 4

347--354

EN

Particularly in terms of carbon fiber (CF) rovings and further high performance fibers, it is a highly demanding task to clamp technical yarns with low elongations at break during high-speed tensile tests due to their sensitivity to shear stress. For fibers to be tested, a low elongation at break results in short testing times and requires high acceleration. In this paper, four different yarn grips that can be applied with various test machines will be introduced and compared to a wedge screw grip. By using most sensitive CF rovings, advantages and disadvantages of these gripping devices will be qualitatively evaluated by means of testing machines with test speeds of up to 20 m/s and strain rates of up to 200 s-1, respectively. Hence, the reproducibility and precision of test results were considerably enhanced by optimizing the geometry and mass of yarn grips. Moreover, theoretical approaches and calculations for the design of yarn grips suitable for test speeds of up to 100 m/s will be presented.

3

Badania własności mechanicznych materiałów inżynierskich

Król M., Brytan Z.

LAB Laboratoria, Aparatura, Badania

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2018

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R. 23, nr 3

20--24

4

Comparison among Different Constitutive Equations on Investigating Tensile Plastic Behavior and Microstructure in Austempered Ductile Iron

Angella G., Zanardi F.

Journal of Casting & Materials Engineering

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2018

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Vol. 2, no. 1

14--23

EN

The capabilities of different constitutive equations of approximating the tensile flow curves and correlating plastic behavior with the microstructure were investigated in austempered ductile iron ADI 1050. In a previous paper, the microstructure evolution of ADI 1050 during austempering was investigated through quenching the ADI 1050 after 14 increasing austempering times to room temperature. The 14 samples were tensile tested and two classes of constitutive equations were examined in the present paper. The Hollomon-type constitutive equations approximated all of the tensile flow curves of ADI 1050 very well but failed in correlating the plastic behavior with microstructure evolution. Voce-type constitutive equations approximated the tensile flow curves only at high stresses very well but could correlate the plastic behavior with the microstructure evolution of ADI 1050 during austempering excellently. The reason of this success was rationalized in terms of the physical basis of Voce-type equations, while Hollomon-type equations are empirical.

5

Modelling of the material destruction of vertically arranged honeycomb cellular structure

Piekło J., Małysza M., Dańko R.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1300--1308

EN

The paper presents the results of the experimental and numerical analysis of material destruction of honeycomb cellular structure. Based on the experimental research, the results of numerical calculations regarding the compression process were verified along with the correctness of used constitutive numerical model. The destruction was analyzed for the casting with no structural defects and for the casting with detected porosities. The results were compared to the structural strength of the honeycomb structure manufactured on the CNC machine. The metallic honeycomb structure was manufactured as a casting of Al alloy in the investment casting technology. For manufacturing purposes the honeycomb model was obtained in additive manufacturing process. The castings and the CNC honeycomb were used in the compression test trials. The process was controlled by the displacement and the results were registered as the changes of the height and the force value. Based on the experimental results the numerical model of honeycombs was introduced for the numerical analysis of the energy absorption and compression process. The results showed good correlation between the experiment and FEM (Finite Element Method) analysis.

6

Effect of preservation methods on tensile properties of human femur-ACL-tibial complex (FATC) – a cadaveric study on male subjects

Marieswaran M., Mansoori N., Digge V. K., Jhahjhria S. K., Behera C., Lalwani S., Kalyanasundaram D.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 3

31--42

EN

Deep freezing and storing in formalin are some of the common techniques of human tissue preservation. However, the preservation modes affect the biomechanical properties of the tissues. In this work, the effects of the above-stated preservation techniques are compared with that of fresh cadaveric samples. Methods: FATC samples from male cadavers of age between 60 and 70 years were tested under tensile loading at a strain rate of 0.8 s–1. Fourteen FATC samples from soft embalmed cadavers were preserved for 3 weeks by two methods: (a) 10% formalin and (b) deep freezing at –20 C followed by thawing. Seven FATC samples from fresh cadavers were experimented as control samples. The results were evaluated by a two-stage statistical process of Kruskal–Wallis H test and Mann–Whitney U-test. Results: It was observed that the failure force of fresh cadavers was the highest while that of preserved samples were approximately half the value. Failure elongation of frozen samples exceeded fresh samples while formalin samples failed at lesser elongations. Higher incidence of tibial insertion point or mid-section failures were observed in fresh samples while the higher incidence of ruptures at femoral insertion point was observed in the two preservation methods. Conclusion: Tensile properties of fresh tissues vary significantly from that of formalin preserved or frozen preserved samples.

7

Study of microstructure and mechanical properties of 14% Cr ODS steel produced by hot isostatic pressing followed by hot forging

Oksiuta Z.

Inżynieria Materiałowa

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2016

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Vol. 37, nr 3

126--130

EN

Consolidation by hot isostatic pressing followed by hot forging of a mechanically alloyed ODS Fe–14% Cr–2% W–0.3% Ti–0.3% Y2O3 (in wt %) ferritic steel powder was applied to find the effect of those methods on the microstructure and mechanical properties of the alloy. Microstructure investigations of the ODS steel revealed that after hot isostatic pressing bimodal-like microstructure with fine and coarse grains up to a few microns was observed. Hot forging process, performed at about 900°C with 50% of deformation, did not improved microstructure homogeneity and grains elongated towards radial direction were observed. High temperature tensile tests revealed that hot forging improves the tensile strength of the as-HIPped ODS steel. However, the ductility and upper shelf energy decreased. This can be related to the microstructure of the ODS steel observed for both consolidation methods and emphasises a necessity of further optimization of hot forging parameters.

PL

Artykuł przedstawia problematykę związaną z otrzymywaniem nowej generacji stali ferrytycznych umacnianych nanocząstkami tlenku itru (Oxide Dispersion Strengthened, ODS). Produkowane metodą mechanicznego stopowania (MS) stale ODS ze względu na swoje właściwości: żarowytrzymałość, odporność na pełzanie, mały współczynnik rozszerzalności cieplnej oraz odporność na pęcznienie podczas promieniowania jonizującego są uważane za atrakcyjny materiał strukturalny do budowy reaktora termojądrowego. Zasadniczym problemem dotyczącym otrzymywania stali ODS jest to, że do ich produkcji można użyć tylko pierwiastków, których czas połowicznego rozpadu jest krótki (Reduced Activation Elements). Do grupy pierwiastków stanowiących podstawę do produkcji stali należy zaliczyć: żelazo, chrom, wolfram, tytan, wanad, krzem i węgiel oraz stabilne temperaturowo tlenki Y i Ti. Użycie innych pierwiastków, np.: Mn, Ni, Al, Co, Cu i B, stosowanych powszechnie do produkcji innych gatunków stali nie jest wskazane. Dodatek tlenku itru oraz zanieczyszczenia pochodzące z procesu MS powodują pogorszenie udarności i plastyczności stali. Ponadto stale ferrytyczne o strukturze regularnie przestrzennie centrowanej (RPC) mają wysoką temperaturę progu kruchości (Ductile to Brittle Transition Temperature, DBTT), która jest znacznie powyżej temperatury pokojowej. Na przykład w żaroodpornych stalach ferrytycznych typu PM2000 lub MA957 stwierdzono, że temperatura przejścia ze stanu kruchego w stan plastyczny jest rzędu 100°C. Jednym ze sposobów obniżenia temperatury progu kruchości jest zastosowanie dodatkowej obróbki cieplno-plastycznej. Dlatego celem pracy było otrzymanie przez MS i konsolidację (metodą HIP) stali ODS oraz zastosowanie dodatkowej obróbki cieplno-plastycznej, kucia na gorąco, w celu określenia wpływu tej metody na wybrane właściwości stali.

8

Właściwości mechaniczne kompozytu polietylenowego z proszkiem szklanym

Sikora J. W., Kliszowska A., Noack B.

Przetwórstwo Tworzyw

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2015

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T. 21, Nr 6 (168)

493-502

PL

W Institut für Produktionstechnik of Westsächsische Hochschule Zwickau przeprowadzono badania kompozytu polimerowego na osnowie polietylenu dużej gęstości o nazwie Hostalen GD 7255 z 10% proszku szklanego o nazwie Mikrover. Kompozyt ten został otrzymany w procesie dwuślimakowego wytłaczania z granulowaniem na zimno. W skład stanowiska wchodziła współbieżna wytłaczarka dwuślimakowa ZSK 18 MEGAlab z głowicą wytłaczarską zaopatrzoną w dyszę kołową, wanna chłodząca oraz granulator. Właściwości mechaniczne otrzymanego kompozytu zbadano poprzez wytworzenie odpowiednich próbek metodą wtryskiwania (Krauss Maffei KM 50-55CX) przy zmiennym czasie chłodzenia wypraski oraz objętościowym natężeniu wypływu kompozycji polimerowej do gniazda formy wtryskowej. Określono podstawowe właściwości wytrzymałościowe w próbie statycznego rozciągania oraz twardość metodą Shore'a. Stwierdzono wpływ warunków wtryskiwania na badane właściwości mechaniczne. rozciąganie, twardość.

EN

The studies of polymer composite on high density polyethylene matrix named Hostalen GD 7255 with the 10% addition of glass powder named Mikrover were conducted in the Institut fur Produktionstechnik of Westsachsische Hochschule Zwickau. The composite was received in the process oftwin screw extrusion with cold pelletizing. The stand included a co-rotating twin screw extruder ZSK 18 MEGAlab with the extruder head eąuipped with a circular die, as well as a water cooling bath and a pelletizer. The mechanical properties of the received composite were studied by manufacturing appropriate samples in the injection moulding process (Krauss Maffei KM 50-55CX) at changeable cooling times of the injection moulding parts and volume rate of polymer composite flow to the injection mold cavity. The basic strength properties were determined in the uniaxial tensile testing and hardness was determined by Shore method. It was stated that injection molding conditions influence the studied mechanical properties.

9

Effects of ECAP on the mechanical properties of Mg-Al2O3 nanocomposites

Ballóková B., Besterci M., Sülleiová K., Balog M., Huang S. J.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 69, nr 1

10--17

EN

Purpose: The purpose of this paper is the study of the effect of equal channel angular pressing (ECAP) on the mechanical properties of the Mg-Al2O3 nanocomposites. Magnesium and its alloys have excellent physical and mechanical properties for a number of applications. In particular its high strength: weight ratio makes it an ideal metal for automotive and aerospace applications, where weight reduction is of significant concern. Design/methodology/approach: Severe plastic deformation is a useful methodology to refine the grain size to the submicron or even nanometer size Findings: In the present work the influence of number of passes of ECAP by grain size, evolution of microstructure, mechanical properties and fracture of magnesium composites with different volume fraction of Al2O3 particles has been investigated by means of optical microscopy, tensile tests and scanning electron microscopy. Research limitations/implications: It has been found, that the grain size decreases with increasing number of passes. The mechanical properties of magnesium alloys are significantly influenced by the testing temperature leading to a decrease in the strength, by reinforcement and/or grain reinforcement leading to an increase in the strength. Originality/value: From previous studies, it was found that the MMCs using different size particles and different ECAP passes can improved the mechanical properties. But the research of Mg MMCs reinforcement with different wt.% nanoscale Al2O3 particles is not adequate.

10

Miniature specimen tensile testing of AZ31 alloy processed by ECAP

Procházka R., Džugan J., Kövér M.

Archives of Materials Science and Engineering

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2015

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Vol. 76, nr 2

134--139

EN

Purpose: Evaluation of bulk nanomaterials and ultra-fine grain structures consists mostly of metallographic evaluation and hardness measurement. The documentation of mechanical properties by hardness testing only might be very inaccurate due to the measurement error and sensitivity. Moreover the yield stress, ultimate tensile stress an elongation determined by tensile testing are more suitable for description of mechanical properties. This article promotes miniature tensile testing. Although the miniature tensile testing could be commonly used for description of mechanical properties in SPD materials, it is quite unknown. Design/methodology/approach: In this article the miniature tensile testing was used for determination. of mechanical properties anisotropy in AZ31 alloy processed by ECAP. The verification was performed by comparison of conventional and miniature tensile specimens of the non-deformed bulk material. Findings: From the experimental procedure and results low material consumption during sampling, sampling and measurement simplicity and possibility to measure the properties in various directions are denoted. Research limitations/implications: Future detailed investigation of secondary phase particles and dislocation-precipitate interaction should be performed. This investigation was not performed as it requires transmission electron microscopy. Such investigation will be performed only for chosen specimens to confirm discussed hypotheses. Practical implications: The paper promotes application of miniature tensile testing for determination of mechanical properties in SPD processed materials. Application of this methodology allows determination of mechanical properties from local volume, material save or preformation of several experiments from a single specimen. Originality/value: The finding might be valuable for researchers in SPD field. The originality of this paper is based on novel methodology and its applicability.

11

Determination of input data for the process of validation of own calculation software for basic material data in static strength tests

Lis Z., Szczutkowski M.

Journal of Polish CIMAC

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2012

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Vol. 7, no 3

159-165

EN

The paper deals with the idea of validation of own application software related to data analysis in conditions of an accredited laboratory. Defined conditions require suitable approach to the chosen problem. While the accreditation process is directly connected with ISO/IEC 17025:2005 which refers to ISO 9001:2000 standards the quality management approach has been proposed in order to perform suitable requirements. Tensile testing method sets an example for the discussed topic as well as the application software supporting the method. Among various input data authors do mention i.e. environmental and organizational conditions, personnel qualifications or measurement equipment.

12

Influence of cathodic-protection-induced hydrogenation on mechanical properties of two ship hull plate steels

Jakubowski M., Modelski Ł., Podbereski M.

Polish Maritime Research

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2008

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nr 1

65-71

EN

Tensile testing and Charpy V impact testing results for two ship hull steels: an ordinary strength steel grade A and a higher strength steel grade AH32 each in both as-received conditions and in hydrogenated by zinc protector in salt water conditions. For both steels the hydrogenation has slightly increased yield stress (Re) and elongation (A) and has not influenced ultimate tensile strength (Rm), while reduction of area has been unchanged (A steel) or even decreased (AH32 steel) due to the hydrogenation. The effect of the hydrogenation on Charpy tests results has evidently been beneficial: the increase of Charpy energy and of percent fibrosity (ductility) of fracture appearance as well as a shift down of ductile-brittle transition temperatures have been observed. It seems that the present practice to evaluate the mechanical properties of ship steels by testing the specimens without hydrogenation leads to conservative results. The Authors have hypothesized that the beneficial effect of hydrogenation can occur if the deformation rate is fast enough, the notch is sharp enough (although only for specimens hydrogenated in unstressed conditions) and hydrogen concentration is moderate.

13

Wyznaczanie naprężeń rzeczywistych w próbie rozciągania cienkich drutów miedzianych

Grosman F., Przondziono J.

Rudy i Metale Nieżelazne

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2004

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R. 49, nr 9

447-450

PL

Zaproponowana metodyka obliczeń i opracowane zależności pozwoliły na wyznaczenie naprężeń rzeczywistych występujących w czasie rozciągania cienkich drutów miedzianych (obrobionych cieplnie oraz umocnionych). Wyniki badań wykazały, w jak dużym stopniu wielkość naprężeń rzeczywistych, określona dla zakresu odkształceń plastycznych, różni się od naprężeń umownych. Badania pozwoliły na analizę udziału odkształceń sprężystych w zakresie wydłużenia równomiernego cienkich drutów. Przeprowadzone obliczenia pozwoliły na ustalenie przebiegu krzywej umocnienia i dobranie funkcji naprężenia uplastyczniającego ciągnionych drutów miedzianych. Przedstawiona praca jest szczególnie interesująca dla technologów zajmujących się projektowaniem procesów obróbki plastycznej, gdyż zagadnienie poprawnego opisu plastyczności materiałów jest ściśle związane z doborem optymalnych parametrów technologicznych. Ustalenie poziomu naprężeń rzeczywistych jest równoznaczne z uzyskaniem informacji dotyczących zapasu plastyczności tworzyw, co jest istotne zarówno dla konstruktorów, jak i użytkowników materiałów ciągnionych, zwłaszcza takich, które narażone są na duże obciążenia.

EN

Suggested computation methodology and elaborated dependences, allowed to determine the true stress ocurring during tension of thin copper wires, both heat-treated and work-hardened. Examination results showed how much the magnitude of true stress, determined for plastic strain range, differs from the magnitude of the engineering stress. The tests that were carried out enabled to analyse the participation of elastic strain in the range of uniform elongation of thin wires. It has been stated that the magnitude of elastic strain is only a small part of total strain, both for loads corresponding to the proof strength and the tensile strength. Calculation of the true stress corresponding to the proof strength made it possible to determine the flow stress curves and select the appropriate flow stress equation for the tested drawn wires. The presented paper is important for process engineers who deal with designing metal forming processes. Properly described plasticity of a material is closely connected with a selection of the best technological parameters. Determining the magnitude of true stress means obtaining information about limit of workability of materials. That is important for both designers and users of drawn materials, especially materials under heavy loading.

14

Szacowanie niepewności pomiarów w statycznej próbie rozciągania

Bochnia J., Matecki K.

Problemy Eksploatacji

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2003

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nr 1

65-76

PL

W pracy opisano szacowanie błędów granicznych i niepewności pomiarów typu A i B w statycznej próbie rozciągania. Przedstawiono przykłady obliczania błędów granicznych wyników pomiarów poszczególnych wielkości otrzymanych na podstawie rozciągania próbek o przekroju prostokątnym oraz błędów granicznych i niepewności pomiarów wytrzymałości na rozciąganie próbek okrągłych.

EN

The following paper presents how to estimate border errors end uncertainty of measurements of type A and B in tensile testing. It also presents examples of matching border errors of measurements of individual quantities, obtained on a basis of tensile tests of rectangular specimens as well as border errors and uncertainty of strength measurements of circular specimens.

15

Effect of various drawing process parameters on the level and distribution of mechanical properties in drawn tubes

Rumiński M.

Metallurgy and Foundry Engineering

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2001

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Vol. 27, no. 1

113-127

EN

Experimental analysis of mechanical properties distribution on the cross section of drawn tubes of 1H18N10T steel is presented in the paper. The tubes after solutioning were drawn by sinking according to selected drawing schedules. Hardness curve of the investigated material was constructed. Two techniques were applied to the determination of mechanical properties distribution: the method based on hardness measurements, and testing of specially prepared mini-specimens. Comparative analysis of results obtained from both techniques was performed for selected drawing schedules. The experiments were realized with varying drawing process parameters: amount of reduction, tube wall thickness and profile of die working part (shape of deformation zone). The importance of analysis of mechanical properties in local scale was emphasized, considering complete assessment of material's effort during deformation process. With regard to the fact that the results of investigations meet the expectations, the applied experimental techniques were found useful to the evaluation of the behaviour of a material being deformed. The extended and more detailed analysis of the effect of tool geometry on the behaviour of drawn material was indicated to be advisable.

PL

W pracy przedstawiono analizę doświadczalną rozkladu własności mechanicznych na przekroju poprzecznym ciągnionych rur ze stali 1H18N10T. Rury w stanie przesyconym poddano procesowi ciągnienia na pusto, według określonych schematów. Skonstruowano krzywą twardości badanego materiału. Do wyznaczenia rozkładów własności mechanicznych zastosowano dwie techniki badawcze: metodę opartą na pomiarach twardości oraz metodę badania specjalnie spreparowanych mini-próbek. Dla wybranych schematów ciągnienia dokonano analizy porównawczej wyników uzyskanych z obydwu metod. Badania przeprowadzono przy następujących zmiennych parametrach procesu ciągnienia: wielkości odkształcenia, grubościenności rury oraz kształcie strefy roboczej ciągadła. Podkreślono znaczenie analizy własności mechanicznych w skali lokalnej, z punktu widzenia pełnej oceny wytężenia materiału w procesie odkształcenia. Biorąc pod uwagę fakt, iż uzyskane wyniki badań odpowiadają oczekiwaniom, stwierdzono przydatność zastosowanych metod badawczych do oceny zachowania się materiału poddanego odkształceniu. Wskazano na celowość rozszerzenia i uszczegółowienia analizy wpływu geometrii narzędzia na zachowanie się ciągnionego materiału.

16

Badania struktury i właściwości powłoki barierowej na włóknach węglowych do zbrojenia kompozytów na osnowie stopów aluminium.

Zarański Z., Bojar Z.

Inżynieria Materiałowa

|

2000

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R. XXI, nr 6

482-485

PL

W pracy omówiono wyniki badań powłoki barierowej na włóknach węglowych przeznaczonych do zbrojenia kompozytów na bazie stopów aluminium. Powłokę barierową z węglika krzemu SiC otrzymywano w wyniku reakcji atomów węgla z powierzchni włókien i atomów krzemu z nośnika silikonowego, podczas obróbki w wysokiej temperaturze. W ocenie struktury i właściwości wytworzonej w ten sposób warstewki SiC wykorzystano metodyki badawcze oparte na skaningowej mikroskopii elektronowej, rentgenowskiej analizie fazowej oraz statycznej próbie rozciągania. Stwierdzono, że optymalny, ze względu na właściwości wytrzymałościowe kompozytu aluminium/włókna węglowe stan powłoki barierowej SiC otrzymano dla impregnatu przygotowanego z 1 części żywicy silikonowej i 2,5 części rozpuszczalnika, wygrzewanego następnie w temperaturze 1550 stopni Celsjusza.

EN

The results of investigations of barrier coating on carbon fibres for aluminium-based composite materials have been discussed in this paper. The silicon carbide barrier coating has been obtained, during high temperature treatment, as a result of reaction between carbon atoms from fibre surface and silicon atoms from silicon impregnant. An evaluation of SiC barrier microstructure and properties was based on the scanning electron microscopy, X-ray phase analysis and tensile testing of individual modified fibres. It has been stated that optimal condition of SiC barrier coating has been obtained from the impregnant prepared with 1 part of silicon resin and 2,5 parts of solvent, next heated at 1550 degrees centigrade.