Regularities of the structure formation at the tool inlet area during friction stir welding with a bobbin tool

Abstract

The bobbin-tool friction stir welding (BFSW) process is effective for welding aluminum alloys whose properties are determined by the structural-phase state. In this work, the evolution of the tool inlet area microstructure during the friction stir welding with a bobbin tool of a 20 -mm-thick plate made of AA2024 aluminum alloy was studied. Specific features of the welded joint formation at the initial stage in the central region of the weld and the near-surface one under the shoulder have been revealed. Regularities of the joint densification and structural changes in the material have been determined.