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Hardness Electrochemical behaviour Stress corrosion cracking Slow strain rate tensile test a b s t r a c t A friction stir weldment of AA2219-T87 aluminium alloy was characterised for its microstructure, mechanical properties, corrosion resistance and stress corrosion cracking behaviour. The dissolution and coarsening of the strengthening precipitates in the weld nugget and TMAZ/HAZ regions, respectively, had resulted in the softening of these regions; nevertheless, the weld joint was found to have an efficiency of around 72%. The general corrosion behaviour of the weld nugget was superior to that of the parent. The TMAZ/HAZ regions, and the weld nugget were found to have been galvanically protected in the immersion tests. Both the parent alloy and the friction stir weldment specimens exhibited a good resistance to stress corrosion cracking in 3.5% NaCl solution as was demonstrated by slow strain rate tensile tests performed at nominal strain rates of 10 −6 s −1 and 10 −7 s −1 .

An experimental Al-Cu-Li-Mg-Ag-Zr type alloy in the form of 13 . 7 mm thick plates was studied for its fusion characteristics using gas metal arc welding (GMAW) and pulsed gas metal arc welding (P-GMAW). High copper 2319 filler of 1 . 6 mm diameter was used. The burn-off characteristics of 2319 filler wire in GMAW and P-GMAW were experimentally determined, including the relation between pulse current and pulse duration for the desired one-drop detachment per pulse (ODPP) condition and feasible range of pulse parameters. The effect of welding parameters on bead geometry and shape relationships was investigated through beadon-plate experiments in the welding current range above the spray transition current. Reasonably good weld beads were obtained in P-GMAW at currents as low as 194 A and welding speeds of 45 cm min -1 . P-GMAW yielded significantly higher weld penetration compared to GMAW.

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