EFFECT OF PRODUCTION PROCESS PARAMETERS ON DENSIFICATION, MICROSTRUCTURE AND SELECTED PROPERTIES OF SPARK PLASMA SINTERED Al4Cu-xSiC COMPOSITES

The paper presents the results of a study on the microstructure and hardness measurements of Al4Cu-xSiC (x = 5, 10, 20 and 30 wt.%) composites produced by spark plasma sintering (SPS). The sintering process was carried out in an HP D 25/3 plasma sintering furnace in a vacuum atmosphere, with sintering temperatures of 580 and 600 degrees C and a densification pressure of 50 MPa. The heating rate was 100 degrees C/min and the isothermal holding time at the sintering temperature was 2.5 min. As a reference material, the AlCu matrix was sintered under the same conditions. As a result, composites with a near-full den-sity of 96.5-99.5% were obtained. Microstructure studies were performed employing the techniques of light microscopy, scan-ning, and transmission electron microscopy, along with analysis of the chemical composition in microareas. The test results did not reveal remarkable differences in the microstructure of the investigated composites sintered at 580 and 600 degrees C. The sin-ters have a fine-grained microstructure with a strengthening phase located at the grain boundaries; locally, pores are visible. Increasing the SiC content in the composites promotes the formation of agglomerates of these particles. It was proven that a higher sintering temperature has a positive effect on the hardness of the studied composites.