Review and Analysis of Mechanical Properties of Friction Stir Welds of High Strength Aluminium Alloys

There have been significant advancements of recent in the studies of friction stir welding of high strength Aluminium alloys. These studies cover developments in the welded joint properties of these alloys. This paper reviews some available literature on evolving mechanical properties of friction stir welding of high strength aluminium alloys especially those of 7075 aluminium alloy which happens to be the most versatile member of the high strength aluminium alloy group. This review is aimed at establishing a correlation between the tensile behavior, plate thickness and temper conditions of the 7075 alloy when joined by friction stir welding (FSW) in both similar and dissimilar joints with other metals. The average values of reported ultimate tensile strength, yield strength, and percentage elongation have been calculated and presented. Comparative analysis was made between the tensile properties at different temper designation and plate thickness. The analysis revealed that temper conditions significantly affect the mechanical properties of both the similar and the dissimilar joints and that similar welding at T6 and T651 temper conditions gave higher weld efficiencies than dissimilar welding with other groups in the aluminium series. However plate thickness have little or no influence on the ultimate tensile behaviour, yield strength and elongation of the welds. The review also indicates that there is a range of temperature between which post weld heat treatment (PWHT) could be performed in order to obtain maximum tensile property This paper is a significant approach to enhance high performance joining techniques and the reliability or otherwise of friction stir welding technology to join 7075 aluminium alloys under different heat treatment or temper conditions of the alloys for better industrial applications.