A mesomechanical analysis of the stress–strain localisation in friction stir welds of polycrystalline aluminium alloys

Friction Stir Spot Welding (FSSW) is assumed as an environment-friendly technique, suitable for the spot welding of several materials. Nevertheless, it is consensual that the temperature control during the process is not feasible, since the exact heat generation mechanisms are still unknown. In current work, the heat generation in FSSW of aluminium alloys, was assessed by producing bead-on-plate spot welds using pinless tools. Coated and uncoated tools, with varied diameters and rotational speeds, were tested. Heat treatable (AA2017, AA6082 and AA7075) and non-heat treatable (AA5083) aluminium alloys were welded to assess any possible influence of the base material properties on heat generation. A parametric analysis enabled to establish a relationship between the process parameters and the heat generation. It was found that for rotational speeds higher than 600 rpm, the main process parameter governing the heat generation is the tool diameter. For each tool diameter, a threshold in the welding temperature was identified, which is independent of the rotational speed and of the aluminium alloy being welded. It is demonstrated that, for aluminium alloys, the temperature in FSSW may be controlled using a suitable combination of rotational speed and tool dimensions. The temperature evolution with process parameters was modelled and the model predictions were found to fit satisfactorily the experimental results.

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Optimization of friction stir welding parameters during joining of AA3103 and AA7075 aluminium alloys using Taguchi method

Materials Today Proceedings ◽

10.1016/j.matpr.2021.02.246 ◽

2021 ◽

Author(s):

Anil Raj ◽

J. Pratap Kumar ◽

Anil Melwin Rego ◽

Ivan Sunit Rout

Keyword(s):

Friction Stir Welding ◽

Taguchi Method ◽

Aluminium Alloys ◽

Welding Parameters ◽

Friction Stir

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Optimization of friction stir welding parameters of dissimilar aluminium alloys 6061 and 5083 by using response surface methodology

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211005804 ◽

2021 ◽

pp. 095440622110058

Author(s):

Sanjeev Verma ◽

Vinod Kumar

Keyword(s):

Tensile Strength ◽

Friction Stir Welding ◽

Tilt Angle ◽

Feed Rate ◽

Aluminium Alloys ◽

Welded Joint ◽

Welding Parameters ◽

Friction Stir ◽

Industrial Sectors ◽

Tool Pin

Aluminium and its alloys are lightweight, corrosion-resistant, affordable and high-strength material and find wide applications in shipbuilding, automotive, constructions, aerospace and other industrial sectors. In applications like aerospace, marine and automotive industries, there is a need to join components made of different aluminium alloys, viz. AA6061 and AA5083. In this study friction stir welding (FSW) is used to join dissimilar plates made of AA6061-T6 and AA5083-O. The effect of varying tool pin profile, tool rotation speed, tool feed rate and tilt angle of the tool has been investigated on the tensile strength and percentage elongation of the welded joints. Box-Behkan design, with four input parameters and three levels of each parameter has been employed to decide the set of experimental runs. The regression models have been developed to investigate the influence of welding variables on the tensile strength and elongation of the welded joint. It is revealed that with the increase in welding parameters like tool rpm, tool feed rate and tilt angle of the tool, both the mechanical properties increase, reach a maximum level, followed by a decrease with further increase in the value of parameters. Amongst different types of tool pin profiles used, the FSW tool having straight cylindrical (SC) pin profile is found to yield the maximum strength and elongation of the welded joint for different combinations of welding parameters. Multiple response optimization indicates that the maximum UTS (135.83 MPa) and TE (4.35%) are obtained for the welded joint fabricated using FSW tool having SC pin profile, tilted at 1.11° and operating at tool speed and feed rate of 1568 rpm and 39.53 mm/min., respectively.

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