Effect of cube texture on local softening of friction stir welded joints for nanostructured AA2024 processed by accumulative roll bonding

Abstract

The current research provides an insight into the correlation between the crystallographic textures, microstructure, and hardness of friction stir welded joints in nanostructured AA2024 alloys processed through accumulative roll bonding (ARB). Utilizing varying rotational speeds (250, 500, 750, and 1000 rpm) at a constant traverse tool (150 mm/min) during friction stir welding (FSW), microstructural analyses reveal distinct grain structures and texture components in the nugget zone. The fully recrystallized Cube {001}⟨100⟩ texture-oriented grains appear at the rotational speed of 750 rpm. The hardness profiles of ARB-processed strips after FSW at different rotational speeds show local softening in the nugget zones. There might be a hypothesis concerning the dissolution of stable and metastable precipitates based on generated heat input, providing insights into the mechanisms influencing hardness variations. Notably, the examination of Cube {001}⟨100⟩ texture and its correlation with local softening adds a valuable dimension to the understanding of microstructural changes in FSW of nanostructured AA2024 alloys processed by accumulative roll bonding process.

Keywords

• AA2024 alloys
• Accumulative roll bonding
• Friction stir welding
• Microstructure
• Crystallographic texture
• Hardness