Abstract

Aluminum-magnesium alloy AA5083-H321 is used extensively as a structural material in aerospace, automobile,
and marine applications. Fusion welding processes such as metal inert gas welding, tungsten inert gas welding,
and laser beam (LB) welding generally result in lower joint efficiencies mainly due to defects such as porosity,
large columnar grain structure, loss of strain hardening effect in fusion zone and heat affected zone and loss of
magnesium due to evaporation. Friction stir (FS) welding is a solid state welding process which has been proved
to solve the above-mentioned problems. In this study, bead-on-plate welds were made on 5 mm thick plates of
AA5083-H321 using both LB and FS welding processes. Studies using light microscopy revealed that FS welding
results in fine recrystallized grains in the weld zone. Hardness values and tensile testing of the joints revealed
that FS welding results in superior mechanical properties compared to LB welding process. It is concluded
that FS Welding process resulted in significantly stronger joints and is more suitable to join AA5083-H321
aluminum alloys.