Experimental evaluation and prediction of end-forming behavior of friction stir processed Al6063T6 tubes at different tool traverse speeds

Abstract

In the present work, end forming of friction stir processed (FSPed) Al 6063T6 tubes at varying traverse speeds has been studied. End expansion, reduction, and beading experiments are conducted to evaluate the effect on the mechanical properties of the processed zone, forming load evolution, and tube thinning. Finite element simulations of the end-forming processes are done and the results like load requirement and instabilities are validated. The traverse speed affects the tensile behavior and end forming of tubes significantly. The dislocation density measurement confirms its relation with strain hardening exponent of the processed zone. The tensile properties, end-forming behavior, and energy absorption capacity of the FSPed Al tube encourage the use of such tubes in place of raw tube for end-forming applications, with appropriate parametric optimization. Occurrence of instabilities during end forming needs attention so that the applicability is not restricted. Finally, finite element simulation results on load requirement correlate well with experimental data. The predictions from thickness strain mapping method, specifically the displacement at the onset of instabilities, in beading are acceptable, while considerable difference is seen in tube expansion. Wrinkling predictions during end reduction are encouraging.