Incremental Forming of Friction Stir Processed Wrought Aluminum Alloy

Abstract

Friction Stir processing is a widely accepted surface fortification method which signifies enhanced microstructural development. FSP is a process of changing the microstructural properties of a material by applying strain which results in frictional force and heating. The stirred material experiences dynamic recrystallization because of concurrent deformation and heating. The heat treatable AA2014 has several applications in the field of automobiles, aviation, medical implantation and defence sector due to its high strength/weight ratio and proven ductility. The influence of the base metal strength and microstructural parameters such as grain analysis at different zones for the property development of AA2014-T6 of 3mm size has not been well attempted previously and provides more scope in the present work. The present work has been divided into two major phases. In the initial phase, several experiments were conducted on 3mm thick Al 2014-T6 alloy sheets using friction stir processing. The friction stir processing is domineered by functional input criterions like spindle speed, traverse feed, tilt angle and geometry of the tool. To rationalise the microstructural and strength development, the selected alloy material was subjected to FSP by altering various input parameters such as spindle speed, traverse feed, tool tilt angle and multi-profiled tools. In this study, five different tool geometries were selected to carry out the stir processing procedure. Response surface methodology (RSM) is a statistical approach implementing central composite design. This approach has been used to generate the regression models in order to analyse and predict ultimate, yield tensile strength and % elongation of the processed samples. A quadratic model (second order) was developed using RSM for the assessed responses such as UTS, YTS and percentage elongation.