scholarly journals Study of the local phase composition and morphology of laser welded joints based on titanium and aluminum alloys by diffraction of hard synchrotron radiation

2020 ◽  
Author(s):  
A. I. Ancharov ◽  
A. G. Malikov
Keyword(s):  
Phase Composition ◽  
Aluminum Alloys ◽  
Synchrotron Radiation ◽  
Welded Joints ◽  
Local Phase

scholarly journals DEVELOPMENT OF A TECHNOLOGICAL PROCESS FOR MANUFACTURING WELDED STRUCTURES

2021 ◽  
Vol 4 (5) ◽  
pp. 35-44
Author(s):  
R. El'cov
Keyword(s):  
Phase Composition ◽  
Laser Welding ◽  
Strain Amplitude ◽  
Welded Joints ◽  
Structural Phase ◽  
Diagnostic Methods ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
First Time ◽  
Lithium Alloys

the main goal of this article is to obtain welded permanent joints of modern thermally hardened aluminum and aluminum-lithium alloys made by laser welding, having mechanical characteristics (temporary tensile resistance, yield strength, elongation at break) and structural-phase composition close to or equal to the base alloy. It is shown for the first time that by controlling the parameters of heat treatment of samples with a welded joint of all studied aluminum-lithium alloys, it is possible to purposefully influence the formation of the specified mechanical properties of the weld by changing the structural and phase composition of the weld. The evolution of the struc-tural and phase composition of welded joints of thermally hardened aluminum and aluminum-lithium alloys has been investigated using modern independent diagnostic methods: for the first time, the use of synchrotron radia-tion diffractometry in combination with high-resolution transmission, scanning electron and optical microscopy. The dependences of the increment of deformation under cyclic loading with amplitudes exceeding the elastic limit on temperature are established. For untreated welded joints, it was found that at +85 C, the inhomogeneity of the deformation increment increases, and its speed increases by 8 times for alloy 1461, 5 times for alloy 1420 and 1.5 times for alloy 1441. At a temperature of -60 0C, alloys 1420 and 1461 have hardening stages, during which the value of deformation decreases at given boundary stress values. At +20 0C, there is a uniform increment of defor-mation and an increase in the amplitude of deformation with an increase in the amplitude of stress. At +85 0C, the strain amplitude does not change with increasing stress amplitude, its value is 0.55-0.5 of the strain amplitude at +20 0C. Based on the research results, technological techniques have been developed that allow obtaining me-chanical characteristics and structural-phase compositions of welded joints close to the main alloy during laser welding of aviation thermally hardened aluminum and aluminum-lithium alloys of the Al-Mg-Cu. Al-Mg-Li, Al-Cu-Mg-Li, Al-Cu-Li systems.

scholarly journals Effect of pulse frequency on laser welding on SiCp/6061 aluminum alloys with powder

2021 ◽  
Vol 2079 (1) ◽  
pp. 012022
Author(s):  
Yongchao Jian ◽  
Yan Shi
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloys ◽  
Laser Welding ◽  
Base Metal ◽  
Welded Joints ◽  
Molten Pool ◽  
Particle Distribution ◽  
Pulse Frequency ◽  
Uneven Distribution

Abstract Because of the uneven distribution of reinforcement particles in the molten pool during laser welding of SiCp/6061Al composites with powder, the effect of pulse frequency on the homogenization was studied in this paper. The pulse frequency of welding is changed and the macro morphology of the weld is studied by metallographic microscope. The particle uniformity of reinforcing phase and the porosity of molten pool at different frequencies were compared. The tensile strength of welded joints at different frequencies was tested by universal tensile machine. Finally, when the pulse frequency is 160Hz, the particle distribution of reinforcing phase is the most uniform and the tensile strength is the largest. The tensile strength reaches 267.06MPa, reaching 69.1% of the base metal. When the pulse frequency is 320Hz, the porosity of the weld is the lowest, reaching 1.75%.

scholarly journals Porosity Formation in Thin Welded Joints of Al–MG–LI Alloys

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 348
Author(s):  
Tatyana Olshanskaya ◽  
Elena Fedoseeva
Keyword(s):  
Phase Composition ◽  
Weld Metal ◽  
Fusion Zone ◽  
Residence Time ◽  
Welded Joints ◽  
Liquid State ◽  
Pore Formation ◽  
Vacuum Treatment ◽  
Thermal Vacuum ◽  
Thermal Vacuum Treatment

This work is about the study of the correlation of pore formation in welded joints of Al–MG–LI alloy with zirconium additives with the state of the base metal, thermal vacuum treatment, and welding technologies MIG and EBW. Metallographic analysis has been carried out, the phase composition of the alloy and weld metal has been investigated, and thermal cycles of welding have been calculated, allowing to estimate the residence time of metal in the alloying zone and weld metal in the liquid state. The nature of the allocation of strengthening fine-dispersed phases in the welded joints of the alloy has been determined. The regularity and character of pore formation in welded joints depending on the applicable thermal vacuum treatment (TVT) and welding technology have been revealed. It was established that TVT with subsequent hardening and aging has no effect on the phase composition of the alloy. However, this type of treatment contributes to the formation of a more homogeneous and uniform nature of the separation of fine-dispersed strengthening phases. It was revealed that the MIG technology (metal with and without TVT) is characterized by a large length of the fusion zone, the high residence time of metal in the fusion zone and weld metal in the liquid state, and the formation of pores. Phase formation in the temperature range of the beginning and end of the alloy crystallization occurs not only in the weld at the final stage of crystallization but also in the fusion zone, which may induce pore formation, whereas EBW welding shows the opposite trend and no pores. It was found that EBW technology prevents pore formation and makes it possible to obtain welded joints of 1420 Al alloys of the required quality.

scholarly journals Possibilities of using scanning acoustic microscopy to analyze incompatibilities in braze welded joints

2019 ◽  
Vol 91 (10) ◽  
pp. 7-15
Author(s):  
Tomasz Piwowarczyk ◽  
Marcin Korzeniowski ◽  
Dawid Majewski
Keyword(s):  
Aluminum Alloys ◽  
Welded Joints ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
Ultrasonic Techniques ◽  
Titanium Grade ◽  
Non Destructive

This article explores the possibilities of using non-destructive ultrasonic techniques to analyze the quality of lapped braze-welded joints. The tests were performed for 4 material groups (DC03+ZE steel and X5CrNi18-19 steel, aluminum alloys AW-5754 and AW-6061, titanium Grade 2 and copper Cu-ETP). As part of the work, additional materials and joint processes and its parameters were selected (TIG, MIG, laser). The quality of joints was monitored using scanning acoustic microscopy. Based on the A-scan andC-scan images, potential joints imperfections were determined. The possibilities of using advanced ultrasonic techniques to analyze the quality of braze joints was assessed.

Investigation of the Effect of Implantation of Aluminum Alloys by Gas and Metal Ions on the Structure and Phase Composition of the Implanted Layer

2021 ◽  
Vol 887 ◽  
pp. 235-241
Author(s):  
Viktor V. Ovchinnikov ◽  
Irina A. Kurbatova ◽  
Elena Vladimirovna Luk'yanenko
Keyword(s):  
Phase Composition ◽  
Aluminum Alloys ◽  
Radiation Dose ◽  
Cellular Structure ◽  
Ion Current ◽  
Subgrain Structure ◽  
Entire Volume ◽  
Average Width ◽  
Cladding Layer ◽  
Ion Current Density

The article presents studies of the structure and phase composition of aluminum alloys after ion implantation. It is shown that the effect of accelerated ions (Cu + Pb) (E = 30 keV, j = 100 μA / cm2) on an alloy without a cladding layer already at a dose of 1016 cm - 2 leads to the formation of a developed subgrain structure in the initially deformed alloy. With an increase in the ion current density and radiation dose, the cellular structure of the implanted aluminum alloys becomes more regular - well-formed cells are observed practically throughout the entire volume of the sample under study. The average width of the dislocation-free regions reaches 2.5 μm with the width of the boundaries not exceeding 0.6 μm.

Effects of Ni Interlayer on Microstructure and Properties of Fusion Welded Joints of Magnesium/Aluminum Alloys

2020 ◽  
Vol 47 (7) ◽  
pp. 0702001
Author(s):  
张书迈 Zhang Shumai ◽  
张福全 Zhang Fuquan ◽  
周惦武 Zhou Dianwu ◽  
刘金水 Liu Jinshui ◽  
周鹤 Zhou He
Keyword(s):  
Aluminum Alloys ◽  
Welded Joints ◽  
Microstructure And Properties ◽  
Ni Interlayer ◽  
Fusion Welded Joints

Improvement in Mechanical and Metallurgical Properties of Friction Stir Welded 6061-T6 Aluminum Alloys through Cryogenic Treatment

2019 ◽  
Vol 969 ◽  
pp. 490-495
Author(s):  
K. Tejonadha Babu ◽  
S. Muthukumaran ◽  
C.H. Bharat Kumar ◽  
C. Sathiya Narayanan
Keyword(s):  
Aluminum Alloys ◽  
Welded Joints ◽  
Cryogenic Treatment ◽  
Base Material ◽  
Cryogenic Cooling ◽  
Stir Zone ◽  
Welding Parameters ◽  
Cooling Rates ◽  
Friction Stir ◽  
Metallurgical Properties

An investigation has been made to improve the properties of the friction stir welded (FSW) 6061-T6 aluminum alloys. A cryogenic thermal treatment is developed for the joints during welding and its effects on mechanical and metallurgical properties, and precipitates are evaluated at various welding parameters. The friction stir welded joints with cryogenic treatment attained the better properties than the without cryogenic treatment. The improvement of properties was attributed to the refinement of grain size and to the introduction of a reduction in the softening region of the welded joints. Under cryogenic cooling rates, joints were experienced to the low temperature environments and faster cooling rates, which are contributed to enhance the hardness of the stir zone and heat affected zone regions and the formation of fine grain structure in the stir zone. The results indicated that the formation of finer grains of less than 5 µm in the stir zone, which is smaller than the joints of without cryogenic treatment. Subsequently, mechanical properties drastically improved and the joints achieved a maximum joint efficiency of 74% of the base material

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