Impulse pressing of diamond-containing metal materials

Abstract

He results of a study of the structure and wear resistance of compacts obtained from a finely dispersed mixture on a nickel bond of composition 70% Ni - 25% Cu - 5% Fe (average particle size about 50 μm) with the addition of micropowder diamond with a grain size of 5/3 with a 100% reference concentration were presented. Impulsed pressing of powder materials was carried out using a modified Kolsky method, which makes it possible to control the loading parameters and choose rational modes of powder material compaction with loading pulse durations in the range of 100-400 μs with pressure amplitudes up to 2000 MPa. Impulse pressing was carried out at a temperature of 20 °С. As a result, compacts with relative density of more than 98 % were obtained. Metallographic studies carried out on a NEOPHOT-32 microscope showed that the resulting compacts have a fairly uniform fine-grained structure. The overall pattern of pore distribution is quite uniform, the observed pore shapes are close to spherical and semiregular convex-concave volumes. X-ray microanalysis carried out on an energy-dispersive spectrometer in the mode of scanning along the surface line and transverse sections of the obtained compacts showed that dynamic pressing does not lead to a noticeable change in the distribution of the elements Ni, Cu, Fe, and C over the sample volume. The measurements of the microhardness of compacts showed that dynamic pressing leads to its growth, compared with the same parameter obtained on sheet samples after rolling and sintering. The compacts were tested for wear resistance in the dry friction mode according to the “rotating disk - stationary sample” scheme. The relationships of the mass loss of compacts and the test time are presented. It has been experimentally established that the wear resistance of compacts obtained by impulse pressing and subsequent sintering is higher compared to compacts obtained by traditional modes of pressing and subsequent sintering.