scholarly journals Synchrotron X-Ray Analysis of the Influence of the Magnesium Content on the Absorptance during Full-Penetration Laser Welding of Aluminum

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 797
Author(s):  
Jonas Wagner ◽  
Christian Hagenlocher ◽  
Marc Hummel ◽  
Alexander Olowinsky ◽  
Rudolf Weber ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Laser Beam ◽  
Laser Beam Welding ◽  
Welding Process ◽  
High Strength ◽  
Magnesium Content ◽  
X Ray ◽  
Full Penetration ◽  
Body Production ◽  
High Strength Aluminum Alloys

Full-penetration laser beam welding is characterized by a weld seam whose depth equals the material thickness. It is associated with a stable capillary and is therefore widely used for welding of sheet metal components. The realization of lightweight concepts in car body production requires the application of high-strength aluminum alloys that contain magnesium as an alloying element, which significantly influences the evaporation temperature and pressure. This change of the evaporation processes influences the geometry of the capillary and therefore its absorptance. In order to quantify the influence of magnesium on the capillary, their geometries were captured by means of high-speed synchrotron X-ray imaging during the welding process of the aluminum alloys AA1050A (Al99.5), AA5754 (AlMg3) and AA6016 (AlSi1.2Mg0.4). The 3D-geometries of the capillaries were reconstructed from the intensity distribution in the recorded X-ray images and their absorptance of the incident laser beam was determined by the analysis of the reconstructed 3D-geometry with a raytracing algorithm. The results presented in this paper capture for the first time the influence of the magnesium content in high-strength aluminum alloys on the aspect ratio of the capillary, which explains the reduced absorptance in case of full-penetration laser beam welding of aluminum alloys with a high content of volatile elements. In order to improve the absorptance in full-penetration welding, these findings provide the information required for the deduction of new optimization approaches.

scholarly journals High-Speed X-Ray Investigation of Pore Formation during Full Penetration Laser Beam Welding of AA6016 Aluminum Sheets Contaminated with Lubricants

2020 ◽  
Vol 10 (6) ◽  
pp. 2077 ◽  
Author(s):  
Christian Hagenlocher ◽  
Jannik Lind ◽  
Rudolf Weber ◽  
Thomas Graf
Keyword(s):  
Laser Beam ◽  
Pore Formation ◽  
High Speed ◽  
Laser Beam Welding ◽  
Welding Process ◽  
X Ray ◽  
Aluminum Sheets ◽  
Full Penetration ◽  
X Ray Imaging ◽  
The Stability

The presence of lubricants on the surface of sheets favors the formation of pores in laser welded seams. This formation process was investigated by means of high-speed X-ray imaging of the full penetration laser beam welding process of two AA6016 aluminum sheets in overlap configuration. The measurement of the growth velocity of the bubbles indicated their sudden growth once they started to form. Further analysis of the X-ray images identified the point of origin of the pores: a few millimeters behind the capillary between the two aluminum sheets. The study shows that the lubricant does not affect the stability of the capillary, which evidences that the formation of these pores is not caused by the fluctuations of the capillary. These results explain for the first time why pore formation cannot be avoided by process strategies, which stabilize the capillary, when welding uncleaned sheets.

scholarly journals Microstructure of Joints Made in High-Strength Steels Using the Robotic Laser Beam Welding Process

2020 ◽  
pp. 91-97
Author(s):  
Lechosław Tuz ◽  
Krzysztof Sulikowski
Keyword(s):  
Laser Beam ◽  
Laser Beam Welding ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Hardness Distribution ◽  
Key Factors ◽  
Welding Technology ◽  
Heat Treated ◽  
Made In

The paper presents the evaluation of weldability of unalloyed high strength heat-treated steels using of a laser beam welding robotic station. The key factors and properties affecting the usability of the aforesaid welding technology when welding the above-named steels were identified on the basis of the assessment of the microstructure and the measurements of hardness distribution in the related butt welded joints.

Experimental Factors Concerning X-Ray Residual Stress Measurements in High-Strength Aluminum Alloys

1966 ◽  
Vol 10 ◽  
pp. 284-294
Author(s):  
Michael E. Hilley ◽  
James J. Wert ◽  
Robert S. Goodrich
Keyword(s):  
Aluminum Alloys ◽  
Cold Working ◽  
High Strength ◽  
Tensile Tests ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Nondestructive Technique ◽  
Angular Rotation ◽  
X Ray ◽  
High Strength Aluminum Alloys

AbstractX-ray diffraction as a means of determining stresses has found increasing application in the last few years. This is primarily because it is the only technique by which stresses can be determined without making measurements on the specimen or structure in the unstressed condition and, consequently, it is the only truly nondestructive technique for determining residual stresses. The principles of determining macrostresses on surfaces with commercially available equipment is quite well known and employs either the X-ray diffractometer or back-reflect ion camera techniques. The diffractometer technique was selected for this investigation because of its accuracy and because it allows both macrostresses and microstra in to be analyzed from the change in position and shape of the diffraction peaks. The X-ray analysis actually consisted of two separate phases. The first dealt with the X-ray determination of the elastic constants (Young's modulus and Poisson 's ratio) for several aluminum alloys, including 5083. These values were compared with the theoretical or published values as determined by standard tensile tests and used later in stress calculations. For these tests, a unique stress stage was used which allowed the specimen to be stressed while positioned in the diffractometer, and also have angular rotation about the diffractometer axis that is independent of the rotation of the counter and receiving slit system. The second phase consisted of analyzing different groups of 5083—aluminum alloy specimens which had been subjected to various degrees of cold working by rolling. This analysis consisted not only of the computation of macrostresses, but also of microstrain and change in particle size as a function of percentage reduction in thickness. The final portion of this phase dealt with electro polishing successive layers from the surface of each sample and relating the measured relaxation to the thickness of the layers removed. In this way, stress distribution in depth was obtainable as a function of cold working.

Effect of scandium alloying of filling wire on properties of welded joints of high-strength aluminum alloys

2021 ◽  
pp. 248-257
Author(s):  
V.V. Ovchinnikov ◽  
R.N. Rastopchin ◽  
L.P. Andreeva
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloys ◽  
Weld Metal ◽  
Ultimate Strength ◽  
Welded Joints ◽  
High Strength ◽  
Magnesium Content ◽  
Critical Rate ◽  
Welding Joint ◽  
High Strength Aluminum Alloys

The results of the effect of scandium alloying of additive wires such as SvАМg4 and SvАМg63 on the structure and mechanical properties of welded joints of sheets and plates of 1420 alloy in mechanized single-passing and manual multi-pass welding are presented. It is shown that the introduction of 0.17...0.25 % scandium in the SvАМg4 and SvАМg63 filling wires contributes to decrease in the cracking rate and significant increase in the critical rate of deformation of the sample during welding on the МVТU sample. The level of microporosities and their location in multi-pass welding of plates of 1420 alloy depend on the magnesium content in the filling wire. The alloying of the SvАМg4 and SvАМg63 filling wires by scandium increases the ultimate strength of both the welding joint as whole and the weld metal.

scholarly journals Surface Modification of Aluminum 6061-O Alloy by Plasma Electrolytic Oxidation to Improve Corrosion Resistance Properties

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Dmitry V. Dzhurinskiy ◽  
Stanislav S. Dautov ◽  
Petr G. Shornikov ◽  
Iskander Sh. Akhatov
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
High Strength ◽  
Electrolytic Oxidation ◽  
Coating Layers ◽  
Plasma Electrolytic ◽  
High Strength Aluminum Alloys

In the present investigation, the plasma electrolytic oxidation (PEO) process was employed to form aluminum oxide coating layers to enhance corrosion resistance properties of high-strength aluminum alloys. The formed protective coating layers were examined by means of scanning electron microscopy (SEM) and characterized by several electrochemical techniques, including open circuit potential (OCP), linear potentiodynamic polarization (LP) and electrochemical impedance spectroscopy (EIS). The results were reported in comparison with the bare 6061-O aluminum alloy to determine the corrosion performance of the coated 6061-O alloy. The PEO-treated aluminum alloy showed substantially higher corrosion resistance in comparison with the untreated substrate material. A relationship was found between the coating formation stage, process parameters and the thickness of the oxide-formed layers, which has a measurable influence on enhancing corrosion resistance properties. This study demonstrates promising results of utilizing PEO process to enhance corrosion resistance properties of high-strength aluminum alloys and could be recommended as a method used in industrial applications.

scholarly journals Development of laser welding of high strength aluminium alloy 2024-T4 with controlled thermal cycle

2020 ◽  
Vol 326 ◽  
pp. 08005
Author(s):  
Mete Demirorer ◽  
Wojciech Suder ◽  
Supriyo Ganguly ◽  
Simon Hogg ◽  
Hassam Naeem
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Heat Input ◽  
Thermal Cycle ◽  
Laser Beam Welding ◽  
Base Material ◽  
High Strength ◽  
Cooling Rates ◽  
Aa 2024 ◽  
Welding Processes

An innovative process design, to avoid thermal degradation during autogenous fusion welding of high strength AA 2024-T4 alloy, based on laser beam welding, is being developed. A series of instrumented laser welds in 2 mm thick AA 2024-T4 alloys were made with different processing conditions resulting in different thermal profiles and cooling rates. The welds were examined under SEM, TEM and LOM, and subjected to micro-hardness examination. This allowed us to understand the influence of cooling rate, peak temperature, and thermal cycle on the growth of precipitates, and related degradation in the weld and heat affected area, evident as softening. Although laser beam welding allows significant reduction of heat input, and higher cooling rates, as compared to other high heat input welding processes, this was found insufficient to completely supress coarsening of precipitate in HAZ. To understand the required range of thermal cycles, additional dilatometry tests were carried out using the same base material to understand the time-temperature relationship of precipitate formation. The results were used to design a novel laser welding process with enhanced cooling, such as with copper backing bar and cryogenic cooling.

scholarly journals Accelerated discovery of high-strength aluminum alloys by machine learning

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Jiaheng Li ◽  
Yingbo Zhang ◽  
Xinyu Cao ◽  
Qi Zeng ◽  
Ye Zhuang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Aluminum Alloys ◽  
Mechanical Performance ◽  
High Strength ◽  
Cost Effective ◽  
Alloy System ◽  
Processing Route ◽  
Specific Strength ◽  
Cu Alloy ◽  
High Strength Aluminum Alloys

Abstract Aluminum alloys are attractive for a number of applications due to their high specific strength, and developing new compositions is a major goal in the structural materials community. Here, we investigate the Al-Zn-Mg-Cu alloy system (7xxx series) by machine learning-based composition and process optimization. The discovered optimized alloy is compositionally lean with a high ultimate tensile strength of 952 MPa and 6.3% elongation following a cost-effective processing route. We find that the Al8Cu4Y phase in wrought 7xxx-T6 alloys exists in the form of a nanoscale network structure along sub-grain boundaries besides the common irregular-shaped particles. Our study demonstrates the feasibility of using machine learning to search for 7xxx alloys with good mechanical performance.

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