scholarly journals Additive Friction Stir-Enabled Solid-State Additive Manufacturing for the Repair of 7075 Aluminum Alloy

2019 ◽  
Vol 9 (17) ◽  
pp. 3486 ◽  
Author(s):  
R. Joey Griffiths ◽  
Dylan T. Petersen ◽  
David Garcia ◽  
Hang Z. Yu
Keyword(s):  
Aluminum Alloy ◽  
Additive Manufacturing ◽  
Solid State ◽  
Side Wall ◽  
Fusion Welding ◽  
7075 Aluminum Alloy ◽  
Hole Filling ◽  
Friction Stir ◽  
Advantages And Disadvantages ◽  
Through Hole

The repair of high strength, high performance 7075 aluminum alloy is essential for a broad range of aerospace and defense applications. However, it is challenging to implement it using traditional fusion welding-based approaches, owing to hot cracking and void formation during solidification. Here, the use of an emerging solid-state additive manufacturing technology, additive friction stir deposition, is explored for the repair of volume damages such as through -holes and grooves in 7075 aluminum alloy. Three repair experiments have been conducted: double through-hole filling, single through-hole filling, and long, wide-groove filling. In all experiments, additive friction stir deposition proves to be effective at filling the entire volume. Additionally, sufficient mixing between the deposited material and the side wall of the feature is always observed in the upper portions of the repair. Poor mixing and inadequate repair quality have been observed in deeper portions of the filling in some scenarios. Based on these observations, the advantages and disadvantages of using additive friction stir deposition for repairing volume damages are discussed. High quality and highly flexible repairs are expected with systematic optimization work on process control and repair strategy development in the future.

Effect of Operational Parameters on AA2014 Friction Stir Weldments Using Plain Cylindrical Tool

2014 ◽  
Vol 592-594 ◽  
pp. 216-223
Author(s):  
Nallavelli Ramesh ◽  
K. Palaksha Reddy
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
Fusion Welding ◽  
Basic Material ◽  
Welding Parameters ◽  
Zone Formation ◽  
Friction Stir ◽  
Structural Applications ◽  
Tool Pin ◽  
Joining Process

Aluminum alloys are mostly used for high strength structural applications utilized in aircraft structure, trucks body, military vehicles, bridges and weapons manufacture. Conventional fusion welding of aluminum alloy produces porosity and hot cracks in the welded joint due to incorrect selection of consumables and parameters, which may lead to lower weld toughness and defects in the mechanical properties. The mostly adopted method for welding AA 2014-T6 is solid state joining process. Friction stir welding (FSW) is an emerging solid state of joining process which avoids bulk melting of the basic material, hot cracking and porosity. The welding parameters and tool pin profile play a major role in deciding weld quality. In this investigation, an attempt has been made to understand the various influences of tool rotational speed, welding speed and pin profile of the tool on friction stir processed (FSP) zone formation in joining of AA2014 aluminum alloy. High Carbon High Chromium steel tool of plain cylindrical pin profile is used to fabricate the joints. The average grey relation grade for each level of each factor are calculated and it was found that the optimal settings of the levels of factors Tool rotation speed (A), Weld speed (B) and Tilt angle (C) are A1-B3-C3. The findings from these investigations will be presented and discussed.

Microstructural and Mechanical Properties of a Solid-State Additive Manufactured Magnesium Alloy

2021 ◽  
pp. 1-21
Author(s):  
Thomas Robinson ◽  
Malcolm Williams ◽  
Harish Rao ◽  
Ryan P. Kinser ◽  
Paul Allison ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Solid State ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Process Parameters ◽  
Weight Ratio ◽  
Structural Components ◽  
Friction Stir ◽  
Magnesium Alloy Az31b

Abstract In recent years, additive manufacturing (AM) has gained prominence in rapid prototyping and production of structural components with complex geometries. Magnesium alloys, whose strength-to-weight ratio is superior compared to steel and aluminum alloys, have shown potential in lightweighting applications. However, commercial beam-based AM technologies have limited success with magnesium alloys due to vaporization and hot cracking. Therefore, as an alternative approach, we propose the use of a near net-shape solid-state additive manufacturing process, Additive Friction Stir Deposition (AFSD), to fabricate magnesium alloys in bulk. In this study, a parametric investigation was performed to quantify the effect of process parameters on AFSD build quality including volumetric defects and surface quality in magnesium alloy AZ31B. In order to understand the effect of the AFSD process on structural integrity in the magnesium alloy AZ31B, in-depth microstructure and mechanical property characterization was conducted on a bulk AFSD build fabricated with a set of acceptable process parameters. Results of the microstructure analysis of the as-deposited AFSD build revealed bulk microstructure similar to wrought magnesium alloy AZ31 plate. Additionally, similar hardness measurements were found in AFSD build compared to control wrought specimens. While tensile test results of the as-deposited AFSD build exhibited a 20 percent drop in yield strength, nearly identical ultimate strength was observed compared to the wrought control. The experimental results of this study illustrate the potential of using the AFSD process to additively manufacture Mg alloys for load bearing structural components with achieving wrought-like microstructure and mechanical properties.

Characterization o Solid-State Vortices Associated with the Friction-Stir Welding of Copper to Aluminum

1998 ◽  
Vol 4 (S2) ◽  
pp. 530-531
Author(s):  
R. D. Flores ◽  
L. E. Murr ◽  
E. A. Trillo
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Solid State ◽  
Weld Zone ◽  
Thick Plates ◽  
6061 Aluminum Alloy ◽  
Friction Stir ◽  
The Past ◽  
Joining Process

Although friction-stir welding has been developing as a viable industrial joining process over the past decade, only little attention has been given to the elucidation of associated microstructures. We have recently produced welds of copper to 6061 aluminum alloy using the technique illustrated in Fig. 1. In this process, a steel tool rod (0.6 cm diameter) or head-pin (HP) traverses the seam of 0.64 cm thick plates of copper butted against 6061-T6 aluminum at a rate (T in Fig. 1) of 1 mm/s; and rotating at a speed (R in Fig. 1) of 650 rpm (Fig. 1). A rather remarkable welding of these two materials results at temperatures measured to be around 400°C for 6061-T6 aluminum welded to itself. Consequently, the metals are stirred into one another by extreme plastic deformation which universally seems to involve dynamic recrystallization in the actual weld zone. There is no melting.

Microstructure and Joint Strength of Similar- and Dissimilar Lap Joints Fabricated by Several Advanced Solid-State Welding Methods

2010 ◽  
Vol 654-656 ◽  
pp. 596-601 ◽  
Author(s):  
Shinji Kumai ◽  
Mitsuhiro Watanabe ◽  
Keyan Feng
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
High Speed ◽  
Joint Strength ◽  
Lap Joints ◽  
Back Surface ◽  
Magnetic Pulse ◽  
Oblique Collision ◽  
Friction Stir ◽  
Steel Sheets

Both similar- and dissimilar metal joints, which are difficult to be welded by using ordinary fusion welding methods, were successfully obtained by using several advanced high-speed solid-state joining methods. (1) Al/Al, Cu/Cu, Al/Fe(Steel), Al/Cu, Al/Ni, Cu/Ni and Al/Bulk metallic glass lap joints were magnetic pulse welded by means of mutual high-speed oblique collision of metal sheets at a high speed of about 500m/s. (2) 2xxx aluminum alloy pins were stud-welded to 5xxx alloy aluminum sheets and several kinds of plated steel sheets at a high speed by using a specially designed discharge circuit. The welding was achieved within a few milliseconds without producing any weld marks on the back surface of the plate. (3) 6022 aluminum alloy sheets were friction stir spot welded to steel sheets and various kinds of galvanized and aluminum-plated steel sheets. The welding was achieved within a few seconds. For those joints, joint strength and characteristic joint interface morphology were investigated.

Study on the Precipitation Behavior of Precipitates of 7075 Aluminum Alloy Friction Stir Welding Joint

2020 ◽  
Vol 1003 ◽  
pp. 37-46
Author(s):  
Hao Zhu ◽  
Shao Kang Dong ◽  
Ze Ming Ma ◽  
Jun Wang
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Strain Hardening ◽  
Strengthening Effect ◽  
7075 Aluminum Alloy ◽  
Friction Stir ◽  
Microhardness Distribution ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Precipitated Phases

In this work, the microhardness of 7075 aluminum alloy friction stir welding (FSW) joint was measured by a micro vickers hardness tester, the microstructure of the joints was characterised by microscope, the precipitated phases among the welding nugget zone (WNZ), thermal mechanical affected zone (TMAZ), heat affected zone (HAZ) were affirmed by X-ray diffractometer (XRD) and the lattice fringe of transmission electron microscopy (TEM) high resolution image. Based on this, the precipition behavior of precipitated phases was studied. The results show that the microhardness distribution of the 7075 aluminium alloy FSW joints is heterogeneous in comparison with the base metal (BM). The precipitates in the joint mainly include MgZn rod shape and AlCuMg in elliptical shape. In the WNZ, the main precipitate is AlCuMg, and the fine grain strengthening effect is better, so the microhardness in this zone is relatively high. In the TMAZ, the quantity of AlCuMg decreased while the MgZn2 increased relatively in comparison with the WNZ. At the same time, the effect of the fine grain strengthening was weakened, though the strain hardening increased. Therefore, the microhardness in the TMAZ still decreased. In the HAZ, the quantity of MgZn2 increased furtherly, and there is no strain hardening and fine grain strengthening, so the microhardness of the HAZ was the lowest among the FSW joints. Besides, through comparative tests, the optimal process parameters of friction stir welding of 7075 aluminum alloy were obtained.

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