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 as well as welding speed and its influence on mechanical and metallurgical qualities of aerospace grade 5052 aluminium alloy. The research observation shows the intermediate extent of process parameters indicates enhanced mechanical qualities compared to the lower and higher regimes. With considering different individual tools pin profiles, square pin (SQ) tool geometry yields the highest ultimate tensile strength in comparison with threaded cylindrical, tapered cylindrical, and straight cylindrical tool. 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 effect 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.