2-D Modeling of Friction Stir Welding by Eulerian Formulation

AbstractThis study presents an investigation of the plunge stage in joining AZ31B magnesium alloy with friction stir welding using two different 3D finite element models based on Arbitrary Lagrangian–Eulerian formulation and Coupled Eulerian–Lagrangian formulation. The investigations are made with the ABAQUS program. Johnson–Cook plastic material law and Coulomb friction law are used in both models. Models are compared in terms of temperature, strain distribution, and processing time. In both models, very similar temperature and strain distributions are obtained in the weld zone and the models are validated by experimental results. In addition, with the increase in the rotational speed of the tool, temperature and strain in the welding zone increase similarly in both models. In the model using the Arbitrary Lagrangian–Eulerian formulation, mesh distortions occur when high mesh density is not created in the plunge zone. No problems related to mesh distortion are encountered in the model using Coupled Eulerian–Lagrangian formulation. Moreover, it is found that the model using the Coupled Eulerian–Lagrangian formulation has a lower processing time and this processing time is not affected by the rotational speed of the tool.

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Overview of Texture Evolution during Friction Stir Welding of Stainless Steel Using Crystal Plasticity and EBSD

Materials Science Forum ◽

10.4028/www.scientific.net/msf.550.479 ◽

2007 ◽

Vol 550 ◽

pp. 479-484 ◽

Cited By ~ 1

Author(s):

Jae Hyung Cho ◽

Donald E. Boyce ◽

Paul R. Dawson

Keyword(s):

Stainless Steel ◽

Friction Stir Welding ◽

Crystal Plasticity ◽

Texture Evolution ◽

Three Dimensional ◽

Friction Stir ◽

Tool Shoulder ◽

Eulerian Formulation ◽

Material Points ◽

Tool Pin

Texture evolution during friction stir welding of stainless steel was investigated using both predictions by crystal plasticity and EBSD measurements. Two- and three-dimensional Eulerian formulations are used to model friction stir welding. Plane strain deformation is assumed in a two-dimensional model, and an initial uniform texture changes into a torsion texture with monoclinic sample symmetry after deformation. Around the tool pin, the texture strengthens, weakens and restrengthens repeatedly. It is found from a simple circular streamline model that the relative magnitudes of the deformation rate and spin along the streamlines decide textural stability. In order to consider more complicated material behaviors, such as movement along the thickness direction due to a threaded tool pin and a tool shoulder, a three-dimensional Eulerian formulation is also implemented. Materials starting under the tool shoulder travel down to the bottom, producing the longest material streamlines. Those material points are predicted to have stronger texture components than others. EBSD results are compared with the predictions.

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Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

International Journal of Automotive and Mechanical Engineering ◽

10.15282/ijame.17.3.2020.08.0612 ◽

2020 ◽

Vol 17 (3) ◽

pp. 8150-8159

Author(s):

Kulwant Singh ◽

Gurbhinder Singh ◽

Harmeet Singh

Keyword(s):

Heat Treatment ◽

Friction Stir Welding ◽

Magnesium Alloys ◽

Mechanical Performance ◽

Fuel Efficiency ◽

Research Work ◽

Grain Structure ◽

Tensile Fracture ◽

Friction Stir ◽

The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

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