Wyniki wyszukiwania - BazTech

1

Microstructure and properties of the Al2O3-Ti3AlNb composites.

Samsel K., Garbacz H., Kurzydłowski K.J.

Archives of Materials Science

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2005

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Vol. 26, nr 3

207-219

EN

The study was concerned with the Al2O3-Ti3AlNb composites produced by powder metallurgy. The microstructures of the sintered composites were described qualitatively and quantitatively. The physical and mechanical properties of the samples examined during the experiments included: porosity, hardness, elastic modulus and brittle toughness. It has been shown that the properties of the composites depend not only on their constituents but also on the particular features of their microstructural structure, which in turn depend on the technology employed. The properties of the composites appeared to be intermediate between those of ceramics and those of alloys with intermetallic matrix. They depend, in a non-linear way, on the volumetric shares of the ceramics and the specific surface area of the phase boundaries. The deviations from the linear theory of mixing can be explained in terms of the disintegrated intermetallic precipitates and pores. It has also been found that with increasing volumetric share of the ceramic material, the sizes of the pores and of the intermetallic particles decrease, whereas their shapes remain almost unchanged.

2

Wytwarzanie i własności spiekanych kompozytów stal szbkotnąca-węglik WC-miedź fosforowa

Leżański J., Madej M., Smoleń D.

Kompozyty

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2002

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R. 2, nr 5

283-287

PL

Przedstawiono wyniki badań w zakresie wytwarzania i badania własności spiekanych kompozytów na osnowie stali szybkotnącej z dodatkami węglika WC, miedzi i fosforu w postaci proszku miedzi fosforowej. Określono wpływ zawartości składników na gęstość wyprasek oraz wpływ zawartości składników i temperatury spiekania na strukturę i własności spiekanych kompozytów. Przeprowadzono analizę dylatometryczną procesu spiekania kompozytów. Stwierdzono duży wpływ analizowanych czynników na badane własności.

EN

Attempts have been made to describe the chemical composition and the production process parameter strength and wear resistance composites. The experimental results was partially presented in another publications. In this paper have been studied production and properties of composite high speed steel-tungsten carbide-copper phosphorus. The high speed steel powder was mixed with tungsten carbide WC, copper phosphorus and electrolytic copper. The compositions of the powder mixes were cold compacted uniaxially at 800 MPa. Green compacts were sintered in vacuum at temperatures 1050, 1150 and 1200°C. Dilatometric curves for the sintering are shown in Figure 1. Figure 2 shows the variation in green density for each powder mixes. Attempts include the as sintered density (Fig. 3), densification during sintering (Fig. 4), Brinell hardness (Fig. 5), benching stress (Fig. 6). Microstructural analysis of the as sintered structures required to use a number of techniques, including optical microscopy (Fig. 7), X-ray diffraction (Fig. 8) and EDX analysis (Fig. 9). From the analysis of the obtained results and microstructural observations it may be concluded that the as sintered properties of composites is affected by the composition of powder mixes, depend on contents of tungsten carbide, copper and phosphorus. The present study shown that we can produce fully dense high speed steel based composites. Oversintering leeds to a grain growth which, in consequence, decreases the mechanical strength of the composite materials.

3

Wpływ węglika WC i miedzi fosforowej na strukturę i własności spiekanych kompozytów na osnowie stali szybkotnącej

Leżański J.

Rudy i Metale Nieżelazne

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2001

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R. 46, nr 12

646-650

PL

Celem badań jest opracowanie składu chemicznego i techniki wytwarzania metodami metalurgii proszków nowoczesnych materiałów kompozytowych, odznaczających się dużą odpornością na ścieranie. Wyniki badań obejmują wpływ dodatku węglika wolframu, miedzi fosforowej na własności spiekanych kompozytów na osnowie stali szybkotnącej gatunku M3/2.

EN

The aim of the investigations was elaboration of chemical composition and production technology of modern composites with high abrasion resistance by means of the methods of powder metallurgy. The results, for steel M3/2 are presented.

4

Spiekane kompozyty Cr-Al2O3

Pietrzak K., Chmielewski M.

Kompozyty

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2001

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R. 1, nr 1

16-18

PL

W pracy przedstawiono wyniki prób spiekania, otrzymanych techniką stopowania mechanicznego (ang. mechanical alloying), proszków kompozytowych Cr-Al2O3. Zamieszczono wyniki badań mikrotwardości, gęstości względnej, mikrostruktury oraz analizę składu chemicznego otrzymanych spieków. Badania prowadzono dla proszków o różnym uziarnieniu.

EN

Among the oxide-metal composites, Al2O3-Fe, Al2O3-Cr, Al2O3-W and Al2O3-Ni are of a great technical importance. Recently, because of the situation on the world raw material market and due to the needs of the industry, Al2O3-Cr composites have become a subject of special interest. This very hard material, having high mechanical strength, resistant to sudden changes of temperature within the range from 25 to 1300°C, can work at temperatures up to 1000°C. It is also resistant to oxidation at temperatures up to 1500°C. The composite in question can be used to make tools and constructional elements (parts of jet engines, nozzles, crucibles, thermal screens, etc.). This paper presents the results of investigations concerning the sintering of (obtaining by mechanical alloying technique) Cr-Al2O3 composite powders. Different sintering temperature and different grain size powders (40:56 um - powder 1, 63:71 um - powder 2 and 100:160 um - powder 3) were examined. The presented paper includes the results: - microstructural investigations (Fig. 2), - diffraction patterns of sintered composites (Fig. 3), - measurements of specific density of sintered composites as the function of the sintering temperature and the grain size of powders (Table 2 and Fig. 4), - measurements of microhardness of composites as the function the sintering temperature and the grain size of powders (Table 3 and Fig. 5).