Investigation of the phase composition and mechanical characteristics of laser welded joints of aluminum-lithium alloys

Abstract A study of laser welding of modern aluminum-lithium alloys has been carried out. Optimization of post heat treatment of laser welded joints has been carried out. The change in the structural-phase composition of welded joints was investigated. The strength of welded joints after heat treatment was equal to the strength of the base alloy.

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DEVELOPMENT OF A TECHNOLOGICAL PROCESS FOR MANUFACTURING WELDED STRUCTURES

Construction Materials and Products ◽

10.34031/2618-7183-2021-4-5-35-44 ◽

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.

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Study of the heat treatment effect on the structure and mechanical properties welded joints of aluminum-lithium alloys V-1461 and V-1469

Industrial laboratory Diagnostics of materials ◽

10.26896/1028-6861-2019-85-7-28-35 ◽

2019 ◽

Vol 85 (7) ◽

pp. 28-35

Author(s):

Aleksey A. Skupov ◽

Aleksey V. Scherbakov ◽

Svetlana V. Sbitneva ◽

Eva A. Lukina

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Rare Earth ◽

Welded Joints ◽

Artificial Aging ◽

Welded Joint ◽

Filler Materials ◽

Aluminum Lithium ◽

Aluminum Lithium Alloys ◽

Lithium Alloys

The use of rare earth elements for alloying of aluminum alloys is a promising direction nowadays — filler materials doped with rare earth metals (REM) improve the mechanical properties of welded joints of high-strength aluminum-lithium alloys compared to serial filler material. The results of studying the effect of the composition of alloyed filler materials Sv1209 and Sv1221 and heat treatment mode on the mechanical properties and structure of welded joints of high-strength aluminum-lithium alloys B-1461 and B-1469 are presented. It is shown that the use of filler materials alloyed with rare earth metals in combination with full heat treatment (quenching and artificial aging) carried out after welding provide an increase in the strength characteristics of the welded joint to the level of strength of the base material with sufficiently high ductility and toughness. Metallographic study of welded joints after heat treatment revealed a fine-grained structure in the center of welds attributed to alloying of the filler with REM. Transmission electron microscopy is used to study precipitated hardening phases in welded joints. The round-shaped phase Al3(Sc, Zr) and a fine δ’-phase precipitated upon cooling of the welded joint are present in weld adjacent zone of V-1469 alloy. At the same time, artificial aging after welding results in formation of copper-containing Ω’- and θ’-phases. Quenching and artificial aging of the welded joint resulted in an increase in the size of precipitated hardening T1’-, S’-, θ’-phases and density of their distribution in the grain volume in the heat-affected zone of V-1461 alloy. Thus, heating upon welding leads to uneven phase precipitation, whereas additional artificial aging aggravates the non-uniformity of decomposition through partial dissolution of some phases and coarsening of the other.

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Influence of Heat Treatment of Laser-Welded Joints of Aluminum-Lithium Alloys on the Instability of Plastic Flow

Прикладная механика и техническая физика ◽

10.15372/pmtf20210617 ◽

2021 ◽

Vol 62 (6) ◽

pp. 146-161

Author(s):

E. V. Karpov ◽

A. G. Malikov ◽

A. M. Orishich

Keyword(s):

Heat Treatment ◽

Plastic Flow ◽

Welded Joints ◽

Aluminum Lithium ◽

Aluminum Lithium Alloys ◽

Lithium Alloys

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Lithium depletion during heat treatment of aluminum-lithium alloys

Metallurgical Transactions A ◽

10.1007/bf02643982 ◽

1986 ◽

Vol 17 (4) ◽

pp. 635-643 ◽

Cited By ~ 37

Author(s):

J. M. Papazian ◽

R. L. Schulte ◽

P. N. Adler

Keyword(s):

Heat Treatment ◽

Aluminum Lithium ◽

Lithium Depletion ◽

Aluminum Lithium Alloys ◽

Lithium Alloys

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A Study on Post Weld Heat Treatment of Friction Stir Welded Al2195 Blank for Spin Forming

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1125.190 ◽

2015 ◽

Vol 1125 ◽

pp. 190-194

Author(s):

Jong Hoon Yoon ◽

Joon Tae Yoo ◽

Kyung Ju Min ◽

Ho Sung Lee

Keyword(s):

Heat Treatment ◽

Treatment Process ◽

Heat Treatment Process ◽

Friction Stir ◽

Aluminum Lithium ◽

Materials Research ◽

Superior Mechanical Properties ◽

Increased Strength ◽

Aluminum Lithium Alloys ◽

Lithium Alloys

It is well known that the significant weight reduction and increased strength have placed advanced aluminum-lithium alloys at the forefront of aerospace materials research. For example the use of aluminum-lithium based alloys for rocket fuel tank domes can reduce weight because aluminum-lithium alloys have lower density and higher strength than Al-Cu alloy 2219. However, Al-Li alloys have been shown the inherent low formability characteristic that make them susceptible to cracking during the spinning operations. In this study a novel heat treatment process on the formability of friction stir welded Al-Li alloy blanks are presented. It is shown that the successful heat treatment process has been developed with superior mechanical properties and currently the patent is applied.

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Thermomechanical treatment of welded joints of aluminum-lithium alloys modified by scandium

10.1063/1.5013813 ◽

2017 ◽

Author(s):

A. G. Malikov

Keyword(s):

Thermomechanical Treatment ◽

Welded Joints ◽

Aluminum Lithium ◽

Aluminum Lithium Alloys ◽

Lithium Alloys

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Development of Aluminum-Lithium Alloys Processed by the Rheo Container Process

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.116-117.513 ◽

2006 ◽

Vol 116-117 ◽

pp. 513-517 ◽

Cited By ~ 1

Author(s):

Roger Sauermann ◽

Bernd Friedrich ◽

T. Grimmig ◽

M. Buenck ◽

Andreas Bührig-Polaczek

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Tensile Strength ◽

Collaborative Research ◽

Induction Melting ◽

High Quality ◽

Aluminum Lithium ◽

Semi Solid ◽

Aluminum Lithium Alloys ◽

Lithium Alloys

This investigation describes the development and evaluation of thixoformable alloys on Al-Li-Mg basis in the scope of the collaborative research center SFB 289 at RWTH Aachen University. Scandium and zirconium was added to Al-Li2.1-Mg5.5 (A1420) with the aid of DoE (Design of Experiments) and precursor billets were manufactured by pressure induction melting (PIM). To evaluate the thixoformability of the synthesized alloys high-quality semi solid processed demonstrators were manufactured by the Rheo-Container-Process. Subsequent heat treatment raised the mechanical properties to maximum values of tensile strength of 432MPa, yield strength of 220MPa and an elongation of 13%. The RCP-Process was designed for the special requirements of this high reactive alloy. The paper will present extraordinary benefits in terms of properties and process simpleness for the semi-solid processing of Al-Li alloys.

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