Effect of microstructure and precipitation phenomena on theMechanical behaviour of AA6061-T6 aluminum alloy weld.

In the present study, the effect of microstructure and precipitation phenomenaon the micro hardness of Tungsten Inert Gas (TIG) welded AA6061-T6 aluminum alloyare investigated. The microstructure features showed mainly the grains of aluminum solid solution with the presence of some precipitates at the grain boundaries. Scanning electron microscope micrographs exhibited the presence of Fe-based intermetallic and B-equilibrium precipitates throughout a-Al grains. In the heat-affected zone (HAZ), the dissolution, over-aged and coalescence of precipitates are observed; their hardening effects disappear and a decrease in strength and hardness are noticed.