An investigation on the microstructure, texture and mechanical properties of an optimized friction stir-welded ultrafine-grained Al–0.2 wt% Sc alloy deformed by accumulative roll bonding

Abstract

In this paper, an ultrafine-grained (UFG) Al–0.2 wt% Sc sheet was fabricated by accumulative roll bonding and welded by applying friction stir welding (FSW) process. Additionally, welding process parameters were optimized using Taguchi optimization technique. Microstructural and textural characterizations were performed by scanning electron microscope equipped with electron backscattered diffraction. Analysis of variance and Taguchi results demonstrated that tool rotational speed had the highest statistical influence (P = 60.08%) on mechanical properties. Confirmation test as was performed to verify the optimum FSW parameters also showed that the error between the estimated value of the maximum hardness and its experimental value was 1.99%. As a result, FSW was demonstrated to be highly beneficial for the retention of the UFG microstructure as well as high mechanical properties in the ARB-processed specimen. The orientation distribution function (ODF) results were in good agreement with the generated strain during the FSW process. The microstructural and textural (ODF) results showed that a well-recrystallized equi-axed grain structure having a combination of the $$ B/\bar{B} $$ and C simple-shear textures was finally developed in the stir zone of the optimized welding specimen.