Fracture behaviour of aluminium alloy 2219-T87 welded plates

Aluminium alloy AA 2219 is used in aerospace applications because of its good weldability, stress corrosion resistance, and mechanical properties over a wide temperature range of +250 to -250degreesC The elastic plastic fracture toughness J(1c) has been measured on 7.4 mm thickness autogenous alternating current tungsten inert gas welded plates of 2219-T87 alloy in the as welded condition, using a single specimen technique. The present paper elucidates the variation of J(1c) across the weld joint. The toughness was evaluated at three different locations across the weld, namely, in the weld, fusion boundary, and heat affected zones, and compared with parent metal toughness. It was found that the fracture toughness across the weld it;as higher than the parent metal toughness. The fusion boundary had the lowest toughness among the three Zones across the weld joint. The variation of toughness among the different zones is explained with reference to fractographic observations.