Effect of pre-weld tempers on mechanical and microstructural behavior of dissimilar friction stir welds of AA2014 and AA7075

In this work, friction stir welding of AA2014 and AA7075 has beenperformed indifferent combinationsof T6 and O temperto study the influence of base metal temper on microstructure, mechanical properties, and fracture behavior of developed welds. Four dissimilar welded joints have been developed using optimum process parameters:AA2014-T6 with AA7075-T6, AA2014-O with AA7075-T6, AA2014-T6 with AA7075-O, and AA2014-O with AA7075-O. The stir zonemicrostructurehas been dominated by the base metal placed on the advancing side and hasequiaxed grains without constituent particles. Weld joints' strengthhas beeneither nearly equal or higher than that of low strength base metal,whereas the weld failure has takenplace from the base metal region when at least one base metal was in O temper and from Stir Zone (SZ) when base metal was in T6 temper.