Change of Hot Cracking Susceptibility in Welding of High Strength Aluminum Alloy AA 7075

Holzer, Matthias; Hofmann, Konstantin; Mann, Viktor; Hugger, Florian; Roth, Stephan; Schmidt, Michael

doi:10.1016/j.phpro.2016.08.048

Cited by 30 publications

(11 citation statements)

References 4 publications

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“…Table 6 summarizes these values. According to Holzer et al [21], the tensile strength of the base material (BM) cannot be achieved because of three reasons: the heat distribution causes MZ and TAZ to soften, the loss of volume and the formation of splashes decrease the cross-sectional area and the solidification cracks occur and also reduce the strength.…”

Section: Resultsmentioning

confidence: 99%

Mechanical and Microstructure Characterization of the AA6013-T4 Aluminum Alloy Welded by Laser

moreira

Carvalho

Coelho

et al. 2020

RCT

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Este trabalho tem como objetivo revelar a influência dos parâmetros de soldagem nas características dimensionais, microestruturais e mecânicas da liga AA6013-T4. O material foi escolhido devido às suas excelentes propriedades e por ser amplamente utilizado na indústria aeroespacial. Os parâmetros variáveis do processo empregados foram: a potência do laser de 1200 e 1400 W; e velocidade de soldagem de 0,08 e 0,1 m / s. As juntas foram soldadas a topo, sem adição de metal, e em uma única passagem por um laser Yb: fibra de alta potência. Microscopia óptica e ensaios de tração foram utilizados para caracterizar as amostras soldadas. Os resultados revelaram que a variação dos parâmetros do processo modificou a geometria dos cordões de solda. A microestrutura da solda é composta por dendritas colunares na borda e equiaxial no centro. Zonas de liquição ocorreram próximas às linhas de fusão, propiciando a formação de microporos e microfissuras. Devido à baixa taxa de solidificação, a soldagem obtida com uma potência de laser de 1200 W e velocidade de 0,08 m / s, proporcionou um melhor desempenho nos testes de tração; a tensão máxima, tensão de escoamento e deformação resultaram em 69%, 84% e 22%, respectivamente, em relação ao metal de base. No entanto, a melhor estabilidade do processo foi observada quando uma potência de laser de 1200 W e velocidade de 0,1 m / s foram utilizadas.

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Section: Resultsmentioning

confidence: 99%

Mechanical and Microstructure Characterization of the AA6013-T4 Aluminum Alloy Welded by Laser

moreira

Carvalho

Coelho

et al. 2020

RCT

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“…The formation of the molten zone in all the cases considered is mainly influenced by convective energy transfer. Its shape and the amount of energy invested can lead to the formation of hot cracks (especially when welding high-strength alloys of type 7075) [8]. More effective is the use of laser and laser-plasma welding with such a melting at which the width of the penetration is less than the depth.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

“…The joints of high-strength aluminum alloys of the 7xxx series are more prone to the formation of cracks and pores. In work [8], it is noted that evaporation during laser welding leads to a change in the concentration of volatile elements of magnesium and zinc. This changes the rate of crystallization of the weld and, consequently, the tendency to hot cracking.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Comparison of the features of the formation of joints of aluminum alloy 7075 (Al-Zn-Mg-Cu) by laser, microplasma, and laser-microplasma welding

Korzhyk

Khaskin

Grynyuk

et al. 2022

EEJET

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This paper reports a study into features of the formation of structures of permanent butt joints of plates with a thickness of 1.5 mm made from the high-strength aluminum alloy 7075 of the Al-Zn-Mg-Cu system. Welding by melting these joints was performed using three techniques: laser, microplasma, and hybrid laser-microplasma. To implement the latter two, a compressed arc on a multipolar asymmetric current was used. The purpose of the research was to establish the tendency to the formation of characteristic defects and the possibility of their elimination. It has been determined that during laser welding a small (~5 %) volumetric fraction of defects in the form of pores is formed, residual welding deformations are minimized. There is a decrease in the hardness of the melted metal by 15 % with a simultaneous increase in the hardness of the heat-affected zone (HAZ) by 8...12 % relative to the base metal. In the melted metal, cavities up to 100 μm in size are formed, which are the center of the origin of hot cracks with a length of 25‒30 μm. There are oxide inclusions in the root part of the seam. With microplasma welding, the volume fraction of defects of the melted metal in the form of pores with a size of 10...105 μm increases (up to 25 %). The hardness of the melted metal is reduced by 30 % with the hardness of the HAZ metal close to the base metal. In laser-microplasma welding, the volumetric fraction of defects of the melted metal in the form of pores with a size of 15...25 μm is reduced to 5 %. The hardness of the melted metal is reduced by 15...20 % with the hardness of the HAZ metal close to the base metal. In the lower part of the melted metal, cavities of ~100 μm are formed. No microcracks were found in the seam metal. Analysis of the research results showed the advantage of the laser-microplasma technique. This method reduces the use of laser energy by 40...50 %, the lifetime of the welding pool (0.03...0.05 s) approaches laser welding, it eliminates the danger of burnout of alloying elements.

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“…However, the weldability of these materials is poor, because of their susceptibility to hot cracking [2][3], which is due to their large solidification range. Furthermore, the poor strength and ductility of the weld metal, and grain boundary melting in the heat affected zone (HAZ) [4].…”

Section: Introductionmentioning

confidence: 99%

Effect of Pulsed Current on Joining of 7075 T6 Aluminium Alloy by TIG Welding Process

Belgacem

Benharat

Sakmeche

2022

Advances in Transdisciplinary Engineering

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7075 T6 aluminum alloys are applied in aircraft construction. The success of their weldability is a technological challenge bringing advantages in the lightening of structures. This work was carried out in the aim to analyze the mechanical behavior and microstructural evolution of aluminum alloys 7075 T6 sheets welded by TIG process, by applying a pulsed current. A notable microstructural change occurred in our materials by the thermal effect, resulting in degradation of mechanical properties. The break of samples is privileged in the connecting region, which is characterized by a columnar structure, contributing to reduce the ability of the material to deforme plastically.

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Change of Hot Cracking Susceptibility in Welding of High Strength Aluminum Alloy AA 7075

Cited by 30 publications

References 4 publications

Mechanical and Microstructure Characterization of the AA6013-T4 Aluminum Alloy Welded by Laser

Mechanical and Microstructure Characterization of the AA6013-T4 Aluminum Alloy Welded by Laser

Comparison of the features of the formation of joints of aluminum alloy 7075 (Al-Zn-Mg-Cu) by laser, microplasma, and laser-microplasma welding

Effect of Pulsed Current on Joining of 7075 T6 Aluminium Alloy by TIG Welding Process

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