scholarly journals Methods for producing permanent joints of aluminum and titanium alloys

Author(s):  
B. M. Nemenenok ◽  
I. V. Rafalski ◽  
P. E., Lushchik ◽  
A. A. Radchenko

The results of the analysis of theoretical and experimental studies of methods for producing permanent joints of dissimilar metals and alloys are presented, as well as the advantages, implementation problems and prospects of using friction stir welding to join titanium and aluminum alloys. It is noted that most studies focus on friction stir welding of light metals such as aluminum, copper, magnesium and their alloys. Despite the great scientific and practical interest, the friction stir welding processes of alloys and metal-matrix composite materials based on aluminum and titanium have been studied less thoroughly and require additional attention.Given the variety and complexity of friction stir welding, the lack of a correct assessment of the reactivity, properties and design features of aluminum and titanium alloys can lead to a number of problems associated with a change in the structure of materials and defects in the welding zone, which is accompanied by the inevitable deterioration of the mechanical characteristics of the finished joints.

2013 ◽  
Vol 554-557 ◽  
pp. 1083-1090 ◽  
Author(s):  
Gianluca Buffa ◽  
Livan Fratini ◽  
Matthias Schneider ◽  
Marion Merklein

Friction Stir Welding (FSW) is a solid state welding process patented in 1991 by TWI; initially adopted to weld aluminum alloys, is now being successfully used also for magnesium alloys, copper and steels. The wide diffusion the process is having is due to the possibility to weld materials traditionally considered difficult to be welded or “unweldable” by traditional fusion welding processes due to peculiar thermal and chemical material properties. Additionally, the process allows welding a wide range of sheet thickness (up to 50mm) avoiding typical fusion welding processes defects, like cavities and porosities, with no shielding gas, filling material or joint preparation. Recently, research is focusing on titanium alloys thanks to the high interest that such materials are getting from the industry due to the extremely high strength-weight ratio together with good corrosion resistance properties. Welding of titanium alloys by traditional fusion welding techniques presents several difficulties due to high material reactivity resulting in bonding with oxygen, hydrogen, and nitrogen with consequent embrittlement of the joint. In this way FSW can represent a cost effective and high quality solution. A few studies have been developed on the FSW of titanium alloys butt joints, while there is a complete lack of knowledge as far as different joint morphologies are regarded (lap joints, T joints, etc.). In the paper the results of an experimental campaign on lap joints made out of thin Ti-6Al-4V sheets are presented. The effect of the main process parameters on the micro and macro mechanical properties has been investigated and related to the microstructural transformations occurring during the process because of the thermo-mechanical action of the tool.


Author(s):  
Jamal Sheikh-Ahmad ◽  
Dima Ali ◽  
Firas Jarrar ◽  
Suleyman Deveci

Friction stir welding of high density polyethylene sheets was performed at different rotational and welding speeds and the material temperature close to the welding zone was monitored by infrared thermography and thermocouple measurements. Welding quality was evaluated by macrostructure analysis and tensile testing. Fracture surfaces of the tensile specimens were also analyzed. It was found that weld quality is highly dependent on the temperature of the material in the welding zone. For some specific welding conditions the welding process was unstable due to elevated temperatures reaching the melting point of HDPE. Instability of the welding processes was characterized by cyclic material temperatures and down forces. Decreasing the welding speed and increasing the rotational speed was found to improve weld quality.


2010 ◽  
Vol 638-642 ◽  
pp. 1185-1190 ◽  
Author(s):  
Hui Jie Liu ◽  
Li Zhou ◽  
Yong Xian Huang ◽  
Qi Wei Liu

As a new solid-state welding process, friction stir welding (FSW) has been successfully used for joining low melting point materials such as aluminum and magnesium alloys, but the FSW of high melting point materials such as steels and titanium alloys is still difficult to carry out because of their strict requirements for the FSW tool. Especially for the FSW of titanium alloys, some key technological issues need to solve further. In order to accomplish the FSW of titanium alloys, a specially designed tool system was made. The system was composed of W-Re pin tool, liquid cooling holder and shielding gas shroud. Prior to FSW, the Ti-6Al-4V alloy plates were thermo-hydrogen processed to reduce the deformation resistance and tool wear during the FSW. Based on this, the thermo-hydrogen processed Ti-6Al-4V alloy with different hydrogen content was friction stir welded, and the microstructural characterizations and mechanical properties of the joints were studied. Experimental results showed that the designed tool system can fulfill the requirements of the FSW of titanium alloys, and excellent weld formation and high-strength joint have been obtained from the titanium alloy plates.


2012 ◽  
Vol 628 ◽  
pp. 206-210 ◽  
Author(s):  
Jia Liang Zhang ◽  
Bei Zhi Li ◽  
Xin Chao Zhang ◽  
Qing Xia Wang

Friction stir welding processes involve many variables. Engineers and operators often find it difficult to effectively design or control it. The objective of this work is to develop a friction stir welding platform of thin plates to improve welding quality and to increase production efficiency. The study is conducted by using finite element modeling and temperature field analysis technology to obtain optimization parameters, and using virtual instrument, multi-sensor data fusion to monitor the force of the stirring spindle. Experiment results show that the developed platform can reach the requirements of processing quality and is cost-effective.


Author(s):  
Santosh Vanama

<p>The paper propose modelling and fabrication of friction stir welding end-effector for ABB IRB1410 robot. A dynamically developing version of pressure welding processes, join material without reaching the fusion temperature called friction stir welding. As friction stir welding occurs in solid state, no solidification structures are created thereby eliminating the brittle and eutectic phase’s common to fusion welding of high strength aluminium alloys. In this paper, Friction stir welding is applied to aluminum sheets of 2 mm thickness. A prototype setup is developed to monitor the evolution of main forces and tool temperature during the operation. Pressure of a gripper plays a major role for tool rotation and developing torque.  Fabrication of the tool has done. Force calculations are done by placing the sensors on the outer surface of gripper. Methods of evaluating weld quality are surveyed as well.</p>


2009 ◽  
Vol 83-86 ◽  
pp. 1243-1250 ◽  
Author(s):  
R.L.L.P. Cerveira ◽  
G. F. Batalha

The aim is to analyze a junction produced by a Friction Stir Welding (FSW) joining process under multiaxial loading, employing a modified Arcan test that allows an angle variation of the loading in order to evaluate the failure of the FSW weldment as compared to the base material. A short review of the earlier studies and relevant theories about the FSW processes and fracture modes I and II under multiaxial loading are presented and were experimentally evaluated for an AA2024-T3 aluminum alloy sheets (t = 1.6 mm) processed by FSW. The results obtained can serve as a basis to compare the junctions made using FSW and conventional joint methods such as rivets (very common practice in the aeronautical industry).


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