Friction stir welding of 2219-T6 aluminum alloy

À´Ô´ÆÚ¿¯£ºÖйúÓÐÉ«½ðÊôѧ±¨(Ó¢ÎÄ°æ)2005ÄêµÚz2ÆÚ

ÂÛÎÄ×÷Õߣº³ÂÓ­´º Áõ»á½Ü ·ë¼ª²Å

ÎÄÕÂÒ³Â룺75 - 78

Key words£ºaluminum alloy£» friction stir welding£» microstructure£» mechanical property£» fracture location

Abstract: 2219-T6 aluminum alloy was friction stir welded to investigate the microstructures and mechanical properties of the joints. Microstructural analyses show that fine and equiaxed grains form in the weld nugget zone (WNZ) because of continuous dynamic recrystallization. In the thermo-mechanically affected zone (TMAZ), some small grains begin to nucleate inside the deformed pancake-shaped grains as the result of recovery and incomplete recrystallization. In the heat-affected zone (HAZ), the grains are coarsened. Tensile tests show that the tensile strength of the joints increases with the increasing welding speed when the welding speed is smaller than 200 mm/min. The maximum tensile strength is equivalent to 77% of that of the base metal and the fracture occurs in the HAZ on the retreating side. However, when the welding speed is greater than 200¤@mm/min, the mechanical properties of the joints seriously degrade because the void defects are formed in the WNZ on the advancing side and the joints fracture at the defect locations.