Development of Pulsed Cold Metal Transfer and Gas Metal Arc Welding Techniques on High-Strength Aerospace-Grade AA7475-T761

High-strength aluminum alloy (AA7475) sheets are widely used in aerospace sectors due to its better performance, global suitability, and multifunctional features. The welding of AA7475 in the fusion welding process like gas metal arc welding (GMAW) is difficult due to cracks generation. However, the...

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Bibliographic Details
Published in:Journal of materials engineering and performance 2020-11, Vol.29 (11), p.7270-7290
Main Authors: Kumaran, T. A. Vigneshwara, Reddy, S. A. Nithin Joseph, Jerome, S., Anbarasan, N., Arivazhagan, N., Manikandan, M., Sathishkumar, M.
Format: Article
Language:English
Subjects:
Characterization and Evaluation of Materials
Chemistry and Materials Science
Corrosion and Coatings
Engineering Design
Materials Science
Quality Control
Reliability
Safety and Risk
Tribology
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Summary:High-strength aluminum alloy (AA7475) sheets are widely used in aerospace sectors due to its better performance, global suitability, and multifunctional features. The welding of AA7475 in the fusion welding process like gas metal arc welding (GMAW) is difficult due to cracks generation. However, these problems could be overcome by different variants of GMAW process, like pulsed and normal cold metal transfer (PCMT and NCMT) techniques. The main objective of this research work is to deliver a better insight into mechanical and metallurgical properties of butt joint welded AA7475 through PCMT, NCMT, and GMAW techniques with ER5356 and ER4043. The defects-free butt joints were observed for PCMT, NCMT, and GMAW processes with ER5356, whereas the presence of porosities is found for ER4043. The microsegregation of Fe, Si, Mg, Zn, and Cu leads to the emergence of Mg 2 Cu, Mg 2 Si, Al 2 Cu, Al 2 CuMg, MgZn 2 , Mg 2 Zn 11 , and Fe 2 Al 6 phases in the AA7475 weldments. The development of binary brittle intermetallic Mg 2 Si phase affects the tensile strength of all weldments made with ER4043. Better joint efficiency (96.11%), impact toughness (12.1 ± 0.8 J), and microhardness (119 ± 7.4 HV) are found in PCMT with ER5356 compared to other processes. Because of the low heat input utilised, PCMT provides better joint strength and microstructural integrity than NCMT and GMAW.
ISSN:1059-9495
1544-1024
DOI:10.1007/s11665-020-05240-8