Microstructural evolution of 2099 Al-Li alloy during friction stir welding process

Microstructural evolution of friction stir welded 2099 Al-Li alloy was evaluated. Friction stir welding (FSW) resulted in significant grain refinement, dissolution of original phases T-1 (Al2CuLi) and 6' (Al3Li), and precipitation of ultrafine delta' phases in the nugget zone (NZ). In the heat affected zone (HAZ), heavy precipitation of T-1 phases led to a peak hardness of 105 HV. A strong rotated Cube texture {013} < 100 > was obtained in the base metal (BM). After FSW the NZ was characterized by shear texture {111} < 110 >, while Bass texture {110} < 112 > and S texture {123} < 634 > were developed in the thermo-mechanically affected zone (TMAZ). Compared with the BM, the dislocation density was decreased in the welding zones, which resulted from recovery and recrystallization. (C) 2016 Elsevier Inc. All rights reserved.