Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy joint

Bibliographic Details
Title: Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy joint
Authors: Shuncun Luo, Yang Tao, Zibin Wu, Xiaonan Wang, Zengrong Hu, Hiromi Nagaumi
Source: Journal of Materials Research and Technology, Vol 35, Iss , Pp 6156-6166 (2025)
Publisher Information: Elsevier, 2025.
Publication Year: 2025
Collection: LCC:Mining engineering. Metallurgy
Subject Terms: Al–Mg–Si–Cu alloy, HAZ softening, Pre-aging, Paint baking, Microstructure, Mechanical properties, Mining engineering. Metallurgy, TN1-997
More Details: The heat-affected zone (HAZ) of the novel Al–Mg–Si–Cu alloy will undergo serious softening during welding. In this work, pre-aging (PA) and paint-baking (PB) processes are proposed to address this issue. The effects of different PA processes and the synergistic effect of PA and PB on the precipitates and properties of Al–Mg–Si–Cu alloy joint are studied. The results show that the degree and mechanism of HAZ softening vary with the distance from the weld center. The most severe softening occurs in HAZ Ⅱ, located 5–7 mm away from the weld center, where coherent β'', QP1/2 and L phases transform into β and Q phases with a weak strengthening effect. The hardness of base metals changes in an S-shaped curve with increasing PA temperature. Compared to the T6 state, the tensile properties of HAZ can only be improved within a PA temperature range of 120–200 °C for 1–4 h. PA inhibits the coarsening of precipitates during welding and promotes the formation of more atomic clusters2 and GP zones in the HAZ, significantly enhancing its tensile properties. Combined with the PA state, the atomic clusters2 and GP zones transform into β'' phases and Cu-containing phases after PB, which further improves the tensile properties of HAZ and significantly increases the hardness of base metals. The joint has the highest bake hardening response when PA is at 140 °C for 1 h. Finally, short-term PA and PB processes are optimized, resulting in a welded joint with a tensile strength of 304.7 MPa and a welding coefficient of 82.2%, demonstrating promising industrial application prospects.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2238-7854
Relation: http://www.sciencedirect.com/science/article/pii/S2238785425004831; https://doaj.org/toc/2238-7854
DOI: 10.1016/j.jmrt.2025.02.236
Access URL: https://doaj.org/article/80e3ad07330a40c68ce727fdfc8d19c0
Accession Number: edsdoj.80e3ad07330a40c68ce727fdfc8d19c0
Database: Directory of Open Access Journals
More Details
ISSN:22387854
DOI:10.1016/j.jmrt.2025.02.236
Published in:Journal of Materials Research and Technology
Language:English