Developments of mathematical models for prediction of tensile properties of dissimilar AA6061-T6 to Cu welds prepared by friction stir welding process using Zn interlayer

Abstract

Amount of intermetallics formed at the weld interface in dissimilar friction stir welding may be reduced by use of suitable interlayer materials such as Zn. In the present investigation, mathematical models have been developed for prediction of tensile properties of dissimilar AA6061-T6 to pure Cu welds prepared by friction stir welding process with Zn interlayer. Experiments were planned as per Box-Behnken design of response surface methodology. Three-factor, three-level Box-Behnken design with 15 runs was employed. Three process parameters: tool rotation speed (710, 1000 and 1400 rpm), tool travel speed (28, 56 and 80 mm/min) and tool pin offset (?0.5, ?1.0 and ?1.5 mm towards AA6061-T6 sheet) were considered. Lacks of fit for the developed models were assessed using analysis of variance (ANOVA). Validities of the developed models were checked by conducting confirmation runs. Predicted and experimental results of confirmation runs were found in reasonable agreements. Microstructural characterization revealed typical microstructure composed of intercalation of base metals. It was observed by X-ray diffraction analysis that use of Zn interlayer coupled with tool offset of ?1.0 and ?1.5 resulted in elimination of intermetallics of Al-Cu system at the weld interface, improving dissimilar weld quality.

Optimization of WEDM process of mould material using Kriging model to improve technological performances

“…The systematic optimizing procedure is displayed in figure 1 in order to develop predictive models and determine optimal values. An experimental matrix generated by the Box-Behnken method is applied to save the experimental costs [26][27][28]. The predictive models of the AKW, the ASR and the CAR are then developed with respect to process parameters using the Kriging approach.…”

Optimal FSW Process Parameters to Improve the Strength of Dissimilar AA6061-T6 to Cu Welds with Zn Interlayer

“…Pandya and Menghani [11] have generated tensile strength properties of dissimilar AA6061-T6 to Cu welds adopting FSW process with Zn interlayer for minimizing intermetallics formation at weld interfaces. They have conducted 15 test runs as per Box-Behnken design of response surface methodology with three FSW process parameters (viz., tool travel speed, tool rotation speed and tool offset) and three levels.…”

“…For easy of reference, the 3 FSW process parameters (viz., tool rotation speed, tool travel speed and tool offset) are designated by A, B and C respectively. The evaluated strength of dissimilar welds, viz., tensile strength, ult  (MPa), yield strength, ys  (MPa) and % elongation from the mathematical models [11] as per L 9 orthogonal array are presented in Table-3.…”

“…Friction stir welding (FSW) process makes the weld joints free from melting-and solidification-related defects, and formed the subject by large number of investigations in the past decade [1-10]. Pandya and [11] have developed mathematical models for tensile properties of dissimilar AA6061-T6 to Cu welds adopting FSW process with Zn interlayer (to minimize intermetallics formation at weld interfaces). They have conducted 15 test runs as per Box-Behnken design of response surface methodology with three factors and three levels.…”

“…Industries prefer simple and reliable procedures to handle optimization problems. Compared to the recently used Box-Behnken design of response surface methodology [11], a simple and modified Taguchi design of experiments is used for the dissimilar welding of AA6061-T6 to Cu with Zn interlayer to obtain the optimal FSW process parameters and the expected range of strength properties. Empirical relation is developed for the tensile strength in terms of FSW process parameters and validated through test results.…”