Investigating Weldability in Microalloyed Al Alloys

Abstract

Aluminum (Al) alloys, especially the 2xxx series due to high strength to weight ratio have found extensive use in aerospace, marine, and automobile industries. The present research trend is microalloying (wt.% < 0.1) these alloys with trace elements viz. Cd, Sn, Ag, In, etc. For these applications, welding becomes an inevitable technique, which is a tougher challenge for Al alloys, and Friction Stir Welding (FSW) is recently explored. In present work, 2219Al alloy and the same alloy microalloyed with 0.06 wt.% Cd were processed by casting route. They were then welded by FSW and mechanical properties and microstructure of the welded joints were studied. The hardness value increased while the impact toughness decreased due to trace addition of Cd. The microstructural study revealed three zones viz. weld nugget zone (WNZ), thermo mechanically affected zone (TMAZ) and heat affected zone (HAZ), identified by the formation of fine, columnar, and spherical grains, respectively.