Fracture analyze of hot pressed diamond-metal matrix compacts containing tin
Zygmunt Nitkiewicz*, Henryk Stokłosa*, Maciej Świerzy** *Politechnika Częstochowska, Wydział Inżynierii Procesowej, Materiałowej i Fizyki Stosowanej, Instytut Inżynierii Materiałowej, al. Armii Krajowej, 42-200 Częstochowa **CF Gomma Poland, Częstochowa
Annals 4 No. 11, 2004 pages 237-242
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abstract The work analyzes the influence of tin presence in chemical composition of powders mixtures on microstructure of diamond- metal matrix hot pressed tools made of them, used for stone cutting. Four pairs of segments containing synthetic diamond grit have been investigated. In each pair one material contained up to 12% wt. of tin, the other one didn’t while proportions of the other elements were the same. The compacts in each pair have been compared to each other. Segments height has been measured in order to estimate their densability. A lot of SEM microphotographs have been taken so that the comparison in microstructure could be performed. The attention has been paid to the samples fracture, way of holding the diamond by surrounding matrix as well as the diamonds’ imprints where the degree of material consolidation could be visible the best. The tin containing compacts compared to those without it had much better consolidation and a smaller distance between the diamond wall and a surrounding matrix thus in turn showing probably higher retention properties. The iron rich matrices those didn’t contain Sn are very agressive environment for diamonds causing its degradation during hot pressing operation. The occurence of small pits on diamond surface has been observed. On the other hand we can hardly recognize the diamond imprint in the fracture of this matrix. The compact itself is the most porous comparing to the others. Key words: diamond tools, hot pressing, powder metallurgy