Estimation of Ultimate Tensile Strength and Percentage of Elongation in Friction Stir Weld Joints of Cryo-Rolled Al–Mg-Si Alloys

Cryo-rolling of aluminium alloys refines the grain structure and improves material characteristics. Due to the advantages of cryo-rolling, efforts have been continuing to commercially produce cryo-rolled aluminium alloys. However, solid-state joining of such grain-refined aluminium alloys has not been investigated yet. Unlike arc welding, friction stir welding (FSW) is a solid-state joining procedure that does not deteriorate the weld metal. The present investigation deals with the use of FSW for the joining of cryo-rolled grain-refined Al-Si alloy. The intention was to avoid the formation of brittle aluminium oxide and hydrogen pick up and to retain the grain-refined characteristics. The tensile testing of the cryo-rolled welded joints indicated adequate strength. The process parameters used in the present investigation together with the tool design resulted in sound friction stir welded joints of cryo-rolled grain-refined Al–Mg-Si alloys. The results reveal that FSW as a process can be well utilised for the joining of cryo-rolled Al–Mg-Si alloys. The FSW process parameter was used to evaluate the mechanical characteristics of cryo-rolled Al–Mg-Si alloys. With respect to the FSW process parameter, a mathematical model was also designed to estimate the tensile strength and elongation of cryo-rolled Al–Mg-Si alloys.