Influence of C02 Laser Beam Welding on Microstructure of Aluminum Metal Matrix Composites Reinforced With Al2O3 Particles

M. Dabalà, M. Magrini
2000 Science and Engineering of Composite Materials  
Keywords: Aluminum alloys, Metal matrix composites, C0 2 Laser welding, Microstructural behavior, Microhardness profiles. Ar as shielding gas was the most effective, both in order to avoid the development of porosity and to reduce the AI2O3 agglomeration. ABSTRACT The continuous C0 2 laser beam welding of two aluminum metal matrix composites (6061 and 2618 reinforced with 20% of A1 2 0 3 ) has been investigated with special attention to the influence of the base alloys, the filler material and
more » ... iller material and the process parameters on the microstructure of the welding bead. In this work square butt welding has been obtained with different C0 2 laser power, feed rate and shielding gases. The microstructure of the welding beads has been examined by optical and electronic microscopy. A migration of the A1 2 0 3 reinforcement particles from the fusion zone (FZ) towards the heat affected zone (HAZ) has been detected and the particles agglomerate near the interface FZ- HAZ. An increase in both porosity and agglomerate sizes inside the welding bead has been observed as the feed rate has been reduced. The hardness of welding beads has been higher than the unaffected composites. A reduction of both the beads hardness and the A1 2 0 3 migration and agglomeration has been obtained by the use of magnesium-rich filler material in the welding process, probably because magnesium is able to increase the reinforcement wettability, and to reduce the rate of formation of spinel phase MgAl 2 0 4 . The use of
doi:10.1515/secm.2000.9.3.123 fatcat:474nvnecajfotpidrhiwjwm5za