Influence of Al2O3 and SiC reinforcements in aluminium matrix composites on its electrodischarge machining (EDM)
Jan Perończyk*, Dionizy Biało** *Politechnika Warszawska, Wydział Mechaniczny Energetyki i Lotnictwa, al. Niepodległości 222, 00-663 Warszawa **Politechnika Warszawska, Wydział Mechatroniki, ul. św. A. Boboli 8, 02-525 Warszawa
Annals 3 No. 8, 2003 pages 366-369
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abstract The paper deals with the problems of the electrodischarge machining (EDM) of the composites with Al-20Si-3Cu-1Mg matrix. As the reinforcing phase Al2O3 and SiC particles with 2.5÷20% volume fraction were used (Table 1). During EDM, holes with 0.5 mm diameter were drilled in plates cutted from composite bars. Average drilling speed vśr and surface roughness Ra were determined. It was presented that energy of the single discharge is the main parameter influencing on EDM process. The higher is energy of the single discharge, the higher is process productivity (Figs. 2 and 3) and the higher is surface roughness of the holes (Figs. 5 and 6). The influence of material and volume fraction of the reinforcing phase in composite on drillingspeed was also noted. When volume fraction of this phase increases, drilling speed decreases (Fig. 4). EDM process of the composites with Al2O3 reinforcement is more difficult then composites with SiC reinforcement because of different thermal conductivity, different electrical resistivity and different melting temperature of these two ceramic materials. Key words: metal matrix composites, electromachining EDM, drilling speed, surface roughness