Fabrication of Tailor-Made Metallic Structures for Lightweight Applications and Mechanical Behaviour

2022 ◽  
pp. 216-261
Author(s):  
R. Ganesh Narayanan ◽  
Perumalla Janaki Ramulu ◽  
Satheeshkumar V. ◽  
Arvind K. Agrawal ◽  
Sumitesh Das ◽  
...  
Keyword(s):  
Adhesive Bonding ◽  
Mechanical Performance ◽  
Dissimilar Materials ◽  
Metallic Structures ◽  
Mechanical Joining ◽  
Lightweight Structures ◽  
Friction Stir ◽  
Tailor Welded Blanks ◽  
Critical Issues ◽  
Novel Methods

Tailor-made metallic structures are fabricated by welding, adhesive bonding, and mechanical joining methods. Here the aim is not only to fabricate lightweight structures, but also to develop novel methods of joining. Lightweight structures are advantageous in several ways including reduction of fuel consumption and vehicle emissions. Developing novel methods of joining is advantageous due to the possibility of joining of dissimilar materials, improved mechanical performance, and microstructures. In the chapter, initially, tailor-welded blanks (TWB) are introduced, and after that, fabrication of TWBs by laser welding, friction stir welding, and friction stir additive manufacturing are elaborately discussed. Some critical issues in modeling the deformation during fabrication of TWBs is also discussed. A brief account of mechanical behavior of adhesive bonded sheets and mechanical joining are presented in the later part.

scholarly journals Improvement on Mechanical Properties of Submerged Friction Stir Joining of Dissimilar Tailor Welded Aluminum Blanks

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
R. Suryanarayanan ◽  
V. G. Sridhar ◽  
L. Natrayan ◽  
S. Kaliappan ◽  
Anjibabu Merneedi ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Mechanical Performance ◽  
Weld Zone ◽  
Tensile Tests ◽  
Welding Parameters ◽  
Negative Effects ◽  
Friction Stir ◽  
Tailor Welded Blanks ◽  
Secondary Precipitates

Friction stir welding is a solid-state welding method that produces joints with superior mechanical and metallurgical properties. However, the negative effects of the thermal cycle during welding dent the mechanical performance of the weld joint. Hence, in this research study, the joining of aluminum tailor welded blanks by friction stir welding is carried out in underwater conditions by varying the welding parameters. The tensile tests revealed that the underwater welded samples showed better results when compared to the air welded samples. Maximum tensile strength of 229.83 MPa was obtained at 1000 rpm, 36 mm/min. The improved tensile strength of the underwater welded samples was credited to the suppression of the precipitation of the secondary precipitates due to the cooling action provided by the water. The lowest hardness of 72 HV was obtained at the edge of the stir zone which indicated the weakest region in the weld zone.

scholarly journals Mechanical Joining Utilizing Friction Stir Forming

2021 ◽  
Vol 1016 ◽  
pp. 1058-1064
Author(s):  
Takahiro Ohashi ◽  
Tadashi Nishihara ◽  
Hamed Mofidi Tabatabaei
Keyword(s):  
High Pressure ◽  
Electric Vehicles ◽  
Dissimilar Materials ◽  
Substrate Material ◽  
Back Surface ◽  
Mechanical Joining ◽  
Friction Stir Process ◽  
Friction Stir ◽  
Mechanical Joints

It is expected that the material ratio of steel for an automobile will decrease rapidly in next decade due to the rise of electric vehicles, and multi-materialization of parts will be promoted consequently. Hence, technologies for dissimilar materials joining have been studied by researchers successfully for recent years. The authors have studied dissimilar materials joining with utilizing friction-stir forming (FSF) approach. The FSF is a friction-stir process invented by Nishihara in 2002. In FSF, a substrate material was put on a die firstly. Next, friction stirring was conducted on the back surface of the material. The material then deformed and filled the cavity of the die due to high pressure and heat caused by the friction stirring. The authors utilized the FSF approach to generate mechanical joints between dissimilar materials. In this presentation, the author introduces various techniques for joining dissimilar materials with employing the FSF.

Classification of Failure Modes in Friction Stir Blind Riveted Lap-Shear Joints With Dissimilar Materials

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Wei-Ming Wang ◽  
Haris Ali Khan ◽  
Jingjing Li ◽  
Scott F. Miller ◽  
A Zachary Trimble
Keyword(s):  
Failure Modes ◽  
Dissimilar Materials ◽  
Polymeric Composite ◽  
Tensile Tests ◽  
Great Promise ◽  
Lightweight Structures ◽  
Friction Stir ◽  
Lap Shear ◽  
Transportation Sector ◽  
Static Tensile

In transportation sector, there is an increasing need for joining dissimilar materials for lightweight structures; however, substantial barriers to the joining of dissimilar materials have led to an investigation and development of new joining techniques. Friction stir blind riveting (FSBR), a newly invented method, has shown great promise in joining complex structures with dissimilar materials. The process can be utilized more effectively if knowledge regarding the failure mechanisms of the FSBR joints becomes available. This research focuses on investigating the different mechanisms that lead to a failure in FSBR joints under lap-shear tensile tests. An in situ, nondestructive, acoustic emission (AE) testing method was applied during quasi-static tensile tests to monitor the initiation and evolution of damage in FSBR joints with different combinations of dissimilar materials (including aluminum, magnesium, and a carbon-fiber reinforced polymeric composite). In addition, a fractographic analysis was conducted to characterize the failure modes. Finally, based on the analysis, the distinct failure modes and damage accumulation processes for the joints were identified. An AE accumulative hit history curve was found to be efficient to discriminate the deformation characteristics, such as the deformation zone and failure mode, which cannot be observed through a traditional extensometer measurement method. In addition, the AE accumulative hit history curve can be applied to predict the failure extension or moment of FSBR joints through an identification of the changes in curve slope. Such slope changes usually occur around the middle of Zone II, which is defined in this study.

scholarly journals Performance of Friction Stir Welded Tailor Welded Blanks in AA5059 and AA6082 Alloys for Marine Applications

2016 ◽  
Vol 710 ◽  
pp. 91-96
Author(s):  
Eduardo E. Feistauer ◽  
Luciano Bergmann ◽  
Jorge Fernandez Dos Santos
Keyword(s):  
Rotational Speed ◽  
Mechanical Performance ◽  
Local Strain ◽  
Tensile Tests ◽  
Image Correlation ◽  
Friction Stir ◽  
Tailor Welded Blanks ◽  
Weld Properties ◽  
Static Tensile ◽  
Marine Applications

Tailor welded blank (TWB) concepts in aluminum alloys, welded by friction stir welding (FSW), are an attractive solution to reduce structural weight of structures applied on the transportation sector. In the present work the mechanical performance and microstructural features of dissimilar friction stir welded TWBs were assessed. Welds were produced with alloys of particular interest to the shipbuilding sector (AA6082 and AA5083, with a thickness combination of 6 and 8 mm respectively) and the effect of rotational speed on the weld properties was investigated. A digital image correlation system (DIC) was used to characterize the local strain fields during the quasi-static tensile tests. Microstructure analysis revealed the presence of a remnant oxide line (ROL) at the stir zone. Moreover, the rotational speed directly affected the ROL distribution and consequently the mechanical properties of the welds. The TWB produced with low rotation speed and high force (600 rpm and 20kN) has shown the highest mechanical performance and failed at the thermo-mechanical affected zone of the AA6082 plate. The micromechanisms of fracture were assessed by SEM and revealed a ductile fracture with large amounts of dimples spread out on the fracture surface.

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

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.

Overlap Friction Stir Welding and Adhesive Bonding AA6082 joints Fatigue

Authorea ◽  
2020 ◽  
Author(s):  
Ricardo Maciel ◽  
Tiago Bento ◽  
Daniel F O Braga ◽  
Lucas da Silva ◽  
Pedro Moreira ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Adhesive Bonding ◽  
Friction Stir

Formation and Structure of Work Material in the Friction Stir Forming Process

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Sladjan Lazarevic ◽  
Kenneth A. Ogata ◽  
Scott F. Miller ◽  
Grant H. Kruger ◽  
Blair E. Carlson
Keyword(s):  
Steel Sheet ◽  
Dissimilar Materials ◽  
Mechanical Interlocking ◽  
Forming Process ◽  
Friction Stir ◽  
Joint Structure ◽  
Work Material ◽  
Formation Zone ◽  
Significant Process ◽  
Geometrical Effects

Friction stir forming (FSF) is a new environmentally friendly manufacturing process for lap joining of dissimilar materials. Fundamentally, this process is based on frictionally heating and mechanically stirring work material of the top piece in a plasticized state to form a mechanical interlocking joint within the bottom material. In this research, the significant process parameters were identified and optimized for Al 6014 alloy and mild steel using a design of experiments (DOE) methodology. The overall joint structure and grain microstructure were mapped as the FSF process progressed and the aluminum work material deformed through different stages. It was found that the work material within the joint exhibited two layers, thermomechanical affected zone, which formed due to the contact pressure and angular momentum of the tool, and heat affected formation zone, which was composed of work material formed through the hole in the steel sheet and into the anvil cavity. Two different geometries of anvil design were employed to investigate geometrical effects during FSF of the aluminum. It was found that the direction and amount of work material deformation under the tool varies from the center to the shoulder.

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