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Abstract

The main objective of the present work was to determine the effect of powder composition on microstructure and properties of iron-base materials used as matrices in diamond impregnated tools. The Fe-Cu-Ni powders premixed and ball-milled for 30 hours, were used for the experiments. The influence of manufacturing process parameters on microstructure and mechanical properties of produced sinters was investigated. Sintering was done by hot-pressing technique in graphite mould. The powders were consolidated to a virtually pore-free condition during 3 minutes hold at 35MPa and 900°C. Investigations of the sintered materials included: density, hardness, static tensile test and X-ray diffraction (XRD) analysis. Microstructural and fractographic observations were also made with a scanning electron microscope (SEM). The obtained results indicate that the sintered parts have a high density, close to the theoretical value, good plasticity, relatively high hardness and yield strength, and are characterized by a coarse-grained microstructure.

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Authors and Affiliations

J. Borowiecka-Jamrozek
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Abstract

In this paper a plastic deformation and a damage evolution in low-carbon cast steel containing non-metallic inclusions are analysed experimentally and numerically. Two microstructures of the cast steel have been obtained after appropriate heat treatment. Tensile tests of smooth specimens and axisymmetric notched specimens have been performed. The notched specimens have the notch radii: 1 mm, 3 mm and 7 mm. Fractography of the specimens was carried out to observe fracture mechanisms. The mechanism depended on the stress state in the notched specimens. The fractography showed the existence of two fracture mechanisms: ductile failure and by shear.
The process of the voids growth formed on the non-metallic inclusions was the process which included in the explanation of the damage mechanism. Modelling of deformation of the specimens has been used with the model suggested by Gurson, Tvergaard and Needleman. The model is implemented in the Abaqus finite element program. The computer simulation was performed using ABAQUS system. The computed output was compared with the experimental results obtained for specimens of the same shape.
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Bibliography

[1] Lachowski, J. & Biel-Gołaska M. (2000). Modelling of Damage Evolution in Cast Steel, Conference Advances in Mechanical Behaviour, Plasticity and Damage EUROMAT 2000, 7-9 November, pp. 1457-1462, Tours, France.
[2] Gurson, A.L. (1977). Continuum theory of ductile rupture by void nucleation and growth. J ournal of Engineering Materials Technology. 99, 2-15.
[3] Tvergaard, V. & Needleman, A. (1984). Analysis of the cup-cone fracture in a round tensile bar. Acta Metallurgica. 32(1), 157-169.
[4] Needleman, A. & Tvergaard, V. (1984). An analysis of ductile rupture in notched bars. J ournal of Mechanics and Physics of Solids. 32(6), 461-490.
[5] Bridgman, P.W. (1952). Studies in Large Plastic Flow and Fracture. Harvard University Press, Cambridge, Massachusetts, Chapter 1.
[6] Biel-Gołaska, M. & Gołaski, L. (1994). The analysis of the ductile failure process of cast steel subjected to triaxial stress states, Foundry Reaserch Institute, Cracow, XLIV, No 1-2, pp. 37-57.
[7] Borowiecka-Jamrozek, J., Lachowski, J. (2014). An analysis of stresses in an Al-5%Si alloy under load, Conference "Recent Trends in Structural Materials", COMAT 2014, Nov. 19-21, pp. 6. Pilzen, Czech Republic.
[8] Koplik, J. & Needleman, A. (1988). Void coalescence in porous plastic solids. International Journal of Solids Structures. 24(8), 835-853.
[9] Richelsen, A.B. & Tvergaard, V. (1994). Dilatant plasticity or upper bound estimates for porous ductile solids. Acta metall materialia. 42(8), 2561-2577.
[10] Tvergaard V. (2001). Crack growth predictions by cohesive zone model for ductile fracture. Journal of Mechanics and Physics of Solids. 49, 2191-2207.
[11] SIMULIA Dassault System, Abaqus analysis user’s manual, Version 6.12 , 2017.
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Authors and Affiliations

J. Lachowski
1
J. Borowiecka-Jamrozek
1

  1. Kielce University of Technology, Al. Tysiąclecia PP. 7, 25-314 Kielce, Poland
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Abstract

This paper discusses the mechanical properties of a material fabricated from commercially available metal powder mixtures designed for

use as a metal matrix of diamond impregnated composites. The mixtures with the catalogue numbers CSA and CSA800 provided by a

Chinese producer are suitable for experimental laboratory testing. The specimens were fabricated in a graphite mould using hot pressing.

The material was tested for density, porosity, hardness, and tensile strength under static loading. A scanning electron microscope (SEM)

was used to analyze the microstructure and cleavage fracture of broken specimens. It was essential to determine how the chemical

composition and the fabrication process affected the microstructure and properties of the material. The properties of the sinters were

compared with those of hot pressed specimens fabricated from sub-micron size cobalt powder (Cobalt SMS). Although the as-consolidated

material is inferior to cobalt, it displays a favourable combination of hardness, yield strength and ductility, and seems to have a great

potential for moderate and general purpose applications.

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Authors and Affiliations

J. Borowiecka-Jamrozek
J. Lachowski
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Abstract

This paper deals with computer modelling of the retention of a synthetic diamond particle in a metallic matrix produced by powder

metallurgy. The analyzed sintered powders can be used as matrices for diamond impregnated tools. First, the behaviour of sintered cobalt

powder was analyzed. The model of a diamond particle embedded in a metallic matrix was created using Abaqus software. The

preliminary analysis was performed to determine the mechanical parameters that are independent of the shape of the crystal. The

calculation results were compared with the experimental data. Next, sintered specimens obtained from two commercially available powder

mixtures were studied. The aim of the investigations was to determine the influence of the mechanical and thermal parameters of the

matrix materials on their retentive properties. The analysis indicated the mechanical parameters that are responsible for the retention of

diamond particles in a matrix. These mechanical variables have been: the elastic energy of particle, the elastic energy of matrix and the

radius of plastic zone around particle.

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Authors and Affiliations

J. Borowiecka-Jamrozek
J. Lachowski
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Abstract

This paper deals with numerical and analytical modelling of a diamond or silicon particle embedded in a metallic matrix. The numerical model of an elastic particle in a metallic matrix was created using the Abaqus software. Truncated octahedron-shaped and spherical-shaped diamond particles were considered. The numerical analysis involved determining the effect of temperature on the elastic and plastic parameters of the matrix material. The analytical model was developed for a spherical particle in a metallic matrix. The comparison of the numerical results with the analytical data indicates that the mechanical parameters responsible for the retention of diamond particles in a metal matrix are: the elastic energy of the particle, the elastic energy of the matrix and the radius of the plastic zone around the particle. An Al-based alloy containing 5% of Si and 2% of Cu was selected to study the mechanical behaviour of silicon precipitates embedded in the aluminium matrix. The model proposed to describe an elastic particle in a metallic matrix can be used to analyze other materials with inclusions or precipitates.
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Authors and Affiliations

J. Lachowski
J.M. Borowiecka-Jamrozek
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Abstract

The paper presents the application of the casting method for the production of porous composites, called syntactic foams, of the casting alloy - solid particles type. This method was used to produce composites based on Al alloys reinforced with particles of clinoptilolite, a natural mineral from the zeolite group. Before the casting process, tests were carried out on the morphology, physicochemical properties and chemical composition of the zeolite, which was obtained from a rock called zeolite tuff, mined in a quarry in Kucin, (VSK PRO-ZEO s.r.o., Slovakia). Observations of the microstructure of the produced composites were also carried out using a scanning electron microscope. Diffractometric tests of zeolite rock as delivered for research and of the produced samples reinforced with zeolite particles were also carried out. Initial studies of the density and porosity of the produced composites were performed. The usefulness of the presented method of composite production was assessed on the basis of the conducted structural tests, with particular emphasis on the particle distribution in the alloy matrix.
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Bibliography

[1] Dyga, R. (2017). Metal foams as structural packing in the construction of process equipment. Technical Transactions Mechanics. 4, 165-178. DOI: 10.4467/2353737XCT.17.057.6368.
[2] Gupta, N. (2007). A functionally graded syntactic foam material for high energy absorption under compression. Materials Letters. 61(4-5), 979-982. https://doi.org/10.1016/j.matlet.2006.06.033.
[3] Taherishargh, M., Sulong, M.A., Belova, I.V. & Murch, G.E. (2015). On the particle size effect in expanded perlite aluminum syntactic foam. Materials and Design. 66(A), 294-303. https://doi.org/10.1016/j.matdes.2014.10.073.
[4] Borowiecka- Jamrozek, J., Depczyński, W. (2017). The effect of the addition of zeolite on the properties of a sintered copper-matrix composite. Metal 2017: 26rd international conference on metallurgy and materials (pp. 1652-1657).
[5] Gottardi, G. & Galli, E. (1985). Natural zeolites, mineral and rocks. Minerals. 18, 256-284. ISBN 3 540 13939 7.
[6] Nanbin, H., Dianyue, G., Bekkum, H. (2001). Introduction to zeolite science and practice. 2nd Completely revised and expanded edition, 137, (pp. 54-59).
[7] Gil, A. (1998). Analysis of the micropore structure of various microporous materials from nitrogen adsorption at 77 K. Adsorption, 4, 197-206.
[8] Jaroniec, M. & Choma, J. (1987). Characterization of activated carbons by distribution function of adsorption potential and micropore dimension. Materials Chemistry and Physics. 18(1-20, 103-117. https://doi.org/10.1016/0254-0584(87)90115-5.
[9] Brunauer, S., Emmett, P.H. & Teller, E. (1938). Adsorption of gases in multimolecular layers. Journal of the American Chemical Society. 60(2), 309-319. https://doi.org/10.1021/ ja01269a023.
[10] Gregg, S.J., Sing, K.S.W. (1982). Adsorption, Surface Area and Porosity. 2 Auglage. London: Academic Press.
[11] Kruk, M., Jaroniec, M. & Gadkaree, K.P. (1997). Nitrogen adsorption studies of novel synthetic active carbons. Journal of Colloid and Interface Science. 192(1), 250-256. DOI: 10.1006/jcis.1997.5009.
[12] Kruk, M., Jaroniec, M. & Sayari, A. (1997). Application of large pore MCM-41 molecular sieves to improve pore size analysis using nitrogen adsorption measurements. Langmuir. 13(23), 6267-6273. https://doi.org/10.1021/la970776m.
[13] Barrett, E.P., Joyner, L.G. & Halenda, P.P. (1951) The determination of pore volume and area distribution in porous substances. I. Computations from nitrogen isotherms. Journal of the American Chemical Society. 73(1), 373-380. https://doi.org/10.1021/ja01145a126
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Authors and Affiliations

J.M. Borowiecka-Jamrozek
1
ORCID: ORCID
M. Kargul
1
ORCID: ORCID

  1. The Kielce University of Technology, Poland
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Abstract

This article discusses results of an analysis of mechanical properties of a sintered material obtained from a mixture of elemental iron, copper and nickel powders ball milled for 60 hours. The powder consolidation was performed by hot pressing in a graphite mould. The hot pressing was carried out for 3 minutes at 900 °C and under a pressure of 35 MPa. The sintered specimens were tested for density, porosity, hardness and tensile strength. Their microstructures and fracture surfaces were also examined using a scanning electron microscope (SEM). The study was conducted in order to determine the suitability of the sintered material for the manufacture of metal-bonded diamond tools. It was important to assess the effects of chemical composition and microstructure of the sintered material on its mechanical properties, which were compared with those of conventional metal bond material produced from a hot-pressed SMS grade cobalt powder. Although the studied material shows slightly lower strength and ductility as compared with cobalt, its hardness and offset yield strength are sufficiently high to meet the criteria for less demanding applications.

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Authors and Affiliations

J. Lachowski
J.M. Borowiecka-Jamrozek
J. Konstanty

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