Tensile properties of dissimilar friction stir weld joints of Al-2024 and Al-7039 alloys

J. Inst. Eng. India Ser. D

2021

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This work investigates the effect of process parameters on joint properties of dissimilar AA6082-T6 and AA7050-T7 friction stir welds and determines the optimal value of process parameters using the grey-based Taguchi technique. At optimum welding parameters, similar friction stir welds of respective parent materials were developed for comparative study. Developed welds were evaluated in terms of macrostructure, microstructure, mechanical properties, and textural behaviour. Two types of plasticized material mixing patterns were observed in the weld nuggets, categorized as intercalated onion ring and interlocking lobes-based flow structures. Through electron backscattered diffraction, the fine nugget grain size was observed in dissimilar weld than weld nugget grain size of similar AA6082-T6 and AA7050-T7 welds. Unlike similar welds, the minimum hardness location lies toward the advancing side for all the dissimilar welds. Dissimilar welds' joint strength and yield strength efficiency were evaluated as 65.65% and 61.25% at optimum welding parameters, respectively. Fracture surface analysis revealed ductile behaviour in all the welded joints.

Section: Resultssupporting

confidence: 86%

A Study on Optimization of Welding Parameters and their Effect on Joint Properties of Dissimilar AA6082-T6 and AA7050-T7 Friction Stir Welds

Singh

J. Inst. Eng. India Ser. D

2021

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“…Dissolution dominated over reprecipitation and resulted in softening. The strength efficiency of weld joints was higher than elongation efficiency [17]. High tensile strength was achieved for dissimilar welds AA2219-AA7475 which was comparable to that of similar joints tensile strength efficiency [18].…”

Section: Introductionmentioning

confidence: 71%

“…During FSW, tool shoulder transport AA7039 from front of AS to back of RS. This flow of material along with incomplete diffusion can be held responsible for the variation of Zn and Cu from As to RS [6,17]. Because of this, dissimilar joints were more heterogeneous than similar joints in which only one material flows for the formation of weld in solid state.…”

Section: Microstructurementioning

confidence: 99%

Microstructure and mechanical behavior of similar and dissimilar AA2024 and AA7039 friction stir welds

Sharma¹,

2020

Eng. rev. (Online)

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In this work, similar and dissimilar friction stir welds of AA2024 and AA7039 were formed using optimized process parameters and truncated threaded tool. Characterization of weld joints for mechanical and microstructural properties was performed by tensile test, micro hardness test, optical microscopy, scanning electron microscopy, and energy dispersive spectrometry. The tensile strength of similar joints was higher than dissimilar joints despite lower microhardness of former. Fracture of FSW joints was found to be started by the fracture of strengthening precipitate θ or η or both in the region of tensile fracture. Dissimilar joints and similar joints of AA7039 exhibited ductile fracture mode while similar joints of AA2024 showed brittle fracture mode.

“…Other dissimilar combinations are 2219 and 7475; 10 2219 and 7039; 11 2024 and 7039; 12 2014 and 7075. 13 FSW of 2014 and 7075 dissimilar alloys is the focus of this research work.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and mechanical properties of dissimilar friction stir welds of AA2014 and AA7075

Kumar

Proceedings of the Institution of Mechanical Engineers, Part E:

Sharma³

2021

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This work investigates the effect of process parameters on microstructure, mechanical properties, and fracture behavior of friction stir welded high-strength aluminum alloys AA2014-T6 and AA7075-T6. Optical micrograph, tensile property, and hardness profile of each weld were determined for analysis, and the tensile fracture surfaces were studied by scanning electron microscope. Welds microstructure were heterogeneous and displayed structures comprising of both base metals and the onion rings were seen in all welds except for the lowest heat input weld. Grains in the weld nugget zone were more refined on the retreating side than the other side. Asymmetric hardness profile had a distinct softened zone on each side whose location and softening extent varied with the processing parameters. Welding speed had a more significant effect on tensile strength than rotary speed and, drastically decreased the same. Faster welding speed formed microscopic defects and changed the appearance of fractured surfaces from flat to zigzag. The welds underwent ductile and mixed-mode tensile failure on the advancing side. Attainment of optimum combination of process parameters is imperative to yield defect-free stronger dissimilar welds