STUDY OF FORMABILITY IMPROVEMENT USING DIFFERENT ANNEALING CYCLES IN INCREMENTAL SHEET FORMING OF AA6061 T6

The formability of AA6061 T6 aluminium alloy is essential due to its high strength and low ductility, posing challenges in forming processes like Incremental Sheet Forming (ISF). Annealing mitigates internal stresses, reduces material hardness, and enhances ductility, thus improving formability. This study investigates the impact of annealing cycles on the formability, microstructure, and micro-hardness of AA6061 T6 sheets during ISF. Various annealing durations (1-15 hours) were tested, followed by ISF experiments. Results demonstrate a significant formability increase with longer annealing, with nearly 40% higher fracture forming height. Micro-hardness decreases with a longer annealing duration (almost 30%), indicating material softening. Microstructural analysis reveals grain growth and recrystallisation, facilitating plastic deformation and enhancing formability. These findings provide insights into the role of annealing in improving formability and mechanical properties in ISF processes, aiding in identifying optimal annealing duration for enhanced performance.