Prediction of solidification cracking in pulsed laser welding of 2024 aluminum alloy

Sheikhi, Mohsen; Ghaini, F. Malek; Assadi, H.

doi:10.1016/j.actamat.2014.09.002

Cited by 118 publications

(28 citation statements)

References 19 publications

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“…Upon increasing the weld speed from 10.0 to 20.0 mm/s for the 2 nd welding condition, no cracks formed. Sheikhi et al [27] reported that a low solidification rate and a small vulnerable zone were ideal for producing a weld without any cracks. Figures 11(c) and 11(d) show that the stresses in the molten pool under the 1 st welding condition were higher than those under the 2 nd welding condition, and high stresses in the molten pool increased the liquid flow.…”

Section: Discussionmentioning

confidence: 99%

Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine‐Grained Steel

Liu

et al. 2018

Advances in Materials Science and Engineering

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Weld solidification crack prevention in the laser penetration welding process is essential for the strength of the welded component. The formation of solidification cracks can ultimately be attributed to welding residual stresses, and preventive measures should be taken during welding. In this study, the effects of residual stresses on the laser penetration welding quality of ultrafine-grained steels were investigated. A heat source model was established through the analysis of the metallography of the cross section of the heat-affected zone (HAZ) of ultrafine-grained AN420s-grade steel, and the chemical composition of the weld bead was obtained using an FLS980-stm Edinburgh fluorescence spectrometer. Furthermore, the constitutive coupling relation between the temperature and material flow stress was established based on the Gibbs function, and the welding residual stress was obtained by setting trace points in a finite element analysis (FEA) model based on experimental data of the weld bead cross section under different welding conditions. The results show that weld solidification cracks will form when the residual stresses exceed the material flow stresses in the weld bead, and the residual stresses can be decreased through a reasonable increase of the welding speed. The results indicate that the proposed criterion has high accuracy and can be used to predict the formation of weld solidification cracks in the laser penetration welding process.

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Section: Discussionmentioning

confidence: 99%

Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine‐Grained Steel

Liu

et al. 2018

Advances in Materials Science and Engineering

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“…The higher temperature according to them provided a low viscous and sufficient liquid phase spread, thereby enhancing the 'metallurgical bonding of adjacent layers'. The long stay of the liquid phase due to the low scan speed allows for sufficient 'flow between dendrites and backfill the dendrites shrinkages' [34,35]. However, the lowest relative density of 83.9% is realized using the lowest energy density of 20 J mm −3 with the highest scan speed of 500 mm s −1 .…”

Section: Effect Of Energy Density On Densification Behavior Of Partsmentioning

confidence: 99%

Experimental investigation of the effect of processing parameters on densification, microstructure and hardness of selective laser melted 7075 aluminium alloy

Mbakaan²,

Barki

2020

Mater. Res. Express

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The 7075 aluminum alloy of the 7xxx series largely used for structures in modern aircraft has been successfully fabricated using selective laser melting (SLM) technology. The morphology of the initial 7075 aluminum alloy powders was characterized by a Zeiss Evo 50 Scanning electron microscope (SEM). Energy Dispersive x-ray (EDX) spectrometer attached to SEM was used as a tool to obtain the chemical composition of the powders. Processing parameters including scan speed, hatch distance and constant laser power (100 and 150 W) effect on densification, microstructure and hardness were investigated. The initial powder particles were found to be elongated and non-spherical and composed of Al, Zn, Mg, Cu, and Ag without Si. The result of the influence of processing parameters on properties of the as-built samples by SLM technology indicates that higher densification of parts can be gained using higher laser power and lower laser scan speed and hatch distance due to significant reduction in the number of pores. Two major types of pores including metallurgical and keyhole pores have been identified with the keyhole pores dominating the samples processed by low laser power of 100 W. The keyhole pores increase in size at a high scan speed and hatch distances. By using higher laser power of 150 W, the keyhole pores reduced significantly while metallurgical pores appear. The result of the hardness test conducted on the samples shows that high values of hardness can be achieved with low scan speed.

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“…In some cases, the aforementioned monitoring techniques with the implementation of signal and image processing algorithms were capable of identifying pores up to 200 μm [16]. On the other hand, Sheikhi [17] and Lippold [18] investigated into the clear mechanism of the hot cracking phenomenon. As it was reported in [17], most forms of cracking resulted from the shrinkage strains that occurred as the weld metal was cooling down.…”

Section: In-process Quality Assessment Of Laser Weldingmentioning

confidence: 99%

“…On the other hand, Sheikhi [17] and Lippold [18] investigated into the clear mechanism of the hot cracking phenomenon. As it was reported in [17], most forms of cracking resulted from the shrinkage strains that occurred as the weld metal was cooling down. There are two opposing forces: the stresses induced by the shrinkage of the metal, and the surrounding rigidity of the base material.…”

Section: In-process Quality Assessment Of Laser Weldingmentioning

confidence: 99%

Quality assessment in laser welding: a critical review

Stavridis

Papacharalampopoulos

Stavropoulos

2017

Int J Adv Manuf Technol

171

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Quality assessment methods and techniques for laser welding have been developed both in-and post-process. This paper summarizes and presents relevant studies being classified according to the technology implemented (vision, camera, acoustic emissions, ultrasonic testing (UT), eddy current technique (ECT)) for the quality inspection. Furthermore, the current review aims to map the existing modeling approaches used to correlating measured weld characteristics and defects with the process parameters. Research gaps and implications of the quality assessment in laser welding are also described, and a future outlook of the research in the particular field is provided.

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Prediction of solidification cracking in pulsed laser welding of 2024 aluminum alloy

Cited by 118 publications

References 19 publications

Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine‐Grained Steel

Numerical Investigations on Residual Stress in Laser Penetration Welding Process of Ultrafine‐Grained Steel

Experimental investigation of the effect of processing parameters on densification, microstructure and hardness of selective laser melted 7075 aluminium alloy

Quality assessment in laser welding: a critical review

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