Influence of process parameters on mechanical and microstructural properties of friction stir welded AA5052

Abstract

ABSTRACT The current research work explores the process parameters namely tool shoulder diameter, tool pin design, tool rotational and welding speed and its influence on mechanical and metallurgical qualities of aerospace-grade 5052 aluminium alloy. The research observation shows that the intermediate extent of process parameters indicates enhanced mechanical qualities compared to the lower and higher regimes. When considering different individual tool pin profiles, square pin (SQ) tool geometry yields the highest ultimate tensile strength in comparison with threaded cylindrical, tapered cylindrical and straight cylindrical tools. A set of the best combination of process parameters with 24 mm shoulder diameter SQ pin tool geometry at tool rotational speed of 1000 rev/min along with the welding speed of 40 mm/min produced defect-free joint with excellent mechanical characteristics with an ultimate tensile strength of 92% compared to the base metal. Microstructural analysis of the best welded specimen (considering the above parameters) revealed 81% finer grain compared to base material that leads to enhanced mechanical attributes. Fractography detects ductile fracture of the welded specimen. The effects of individual process parameters on grain size, micro-hardness, flexural strength, bending angle and percentage of elongation of each sample are represented in this research article.