Friction stir welding of aluminum AA6061 & AA8011 using optimization approach based on both Taguchi and grey relational analysis

Abstract

In the advancing age of technology, the use of aluminium alloys has increased in the automotive and various mechanically challenging sectors due to corrosion resistance, lightness, non-toxicity, good thermal conductivity with good strength are very important requirements. Effects such as solidification cracking, distortion and shrinkage arise due to the conventional fusion welding of aluminium alloys. Tailored welding methods such as Friction Stir welding (FSW) have proven to be very effective and cost saving for welding aluminium alloys. But optimal formability parameters and conditions for various cases and combinations of materials are still unknown and the effects of temperature, orientation and strain rates are yet to be determined. That brings us to the objective of the project. In the present work, dissimilar aluminium alloys (AA6061-AA8011) are friction stir welded using optimum process parameters of rotational speed 1120 RPM, traverse speed of 50 mm/min with no tilt. Specimens cut from the welded blanks are then subjected to uni-axial tension test to obtain the mechanical behaviour at different strain rates, temperatures conditions and different orientations with respect to rolling direction of sheet. Taguchi optimization method and Grey Relational Approach (GRA) is applied to determine the optimum parameters for good formability of the material. It is observed that from findings of Tensile Testing, Taguchi and GRA temperature has major impact on material properties of the weld region, with the increase in temperature material properties like elongation, yield and ultimate tensile strength. Thus, temperature plays major role in FSW AA6061 & AA8011 specimens during tensile load application.

Keywords

• Material characterization
• friction stir welding
• ANOVA
• GRA
• tensile properties
• Aerospace Engineering