Copper matrix composites reinforced with steel particles

The paper presents the results of research on the production and application of sintered copper matrix composites reinforced with carbon steel and T15 HSS steel particles. The starting materials for obtaining the sintered composites were commercial powders of copper, carbon steel and T15 HSS steel. Experiments were carried out on specimens containing 2.5, 5, 7.5, and 10% of steel particles by weight. Finished powder mixtures containing appropriate quantities of steel were subjected to single pressing with a hydraulic press at a compaction pressure of 624 MPa. Obtained samples were subjected to a sintering process in a sillit tubular furnace at 900 degrees C in an atmosphere of dissociated ammonia. The sintering time was 2 h. After the sintering process, the samples were cooled in a cooler mounted in the furnace. The obtained sinters were subjected to hardness, density, electrical conductivity, and abrasion resistance measurements. Observations of the microstructure of metallographic specimens made from the sintered compacts were also performed using an optical microscope and scanning electron microscope (SEM). After the abrasion resistance tests, the geometric structure of the surface was observed. The hardness increased in comparison with a sample made of pure copper, whereas the density and electrical conductivity decreased. The highest hardness was obtained for the composite containing 10% of T15 high speed steel particles which amounted 61 HB. This is due to presence of carbides in the steel particles. The highest electrical conductivity was obtained for the composite containing 2.5% of T15 high speed steel which amounted 40 MS/m (68% of solid copper conductivity). Tribological tests have shown that the introduction of high-speed steel particles increases the abrasion resistance of composites.