Growth kinetics of Al–Fe intermetallic compounds during annealing treatment of friction stir lap welds

Journal Article · Tue Apr 01 00:00:00 EDT 2014 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2014.01.023· OSTI ID:22340349

Movahedi, M., E-mail: [e-mail] ^[1]; Kokabi, A.H., E-mail: [e-mail] ^[1]; Seyed Reihani, S.M., E-mail: [e-mail] ^[1]; Najafi, H., E-mail: [e-mail] ^[2]; Farzadfar, S.A., E-mail: [e-mail] ^[3]; Cheng, W.J., E-mail: [e-mail] ^[4]; Wang, C.J., E-mail: [e-mail] ^[4]

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1. Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Ave., Tehran (Iran, Islamic Republic of)
2. Institute of Condensed Matter Physics (ICMP), EPFL, CH-1015 Lausanne (Switzerland)
3. McGill University, Department of Materials Engineering, Montreal, QC H3A 2B2 (Canada)
4. Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, ROC (China)

In this study, we explored the growth kinetics of the Al–Fe intermetallic (IM) layer at the joint interface of the St-12/Al-5083 friction stir lap welds during post-weld annealing treatment at 350, 400 and 450 °C for 30 to 180 min. Optical microscope (OM), field emission gun scanning electron microscope (FEG-SEM) and transmission electron microscope (TEM) were employed to investigate the structure of the weld zone. The thickness and composition of the IM layers were evaluated using image analysis system and electron back-scatter diffraction (EBSD), respectively. Moreover, kernel average misorientation (KAM) analysis was performed to evaluate the level of stored energy in the as-welded state. The results showed that the growth kinetics of the IM layer was not governed by a parabolic diffusion law. Presence of the IM compounds as well as high stored energy near the joint interface of the as-welded sample was recognized to be the origin of the observed deviation from the parabolic diffusion law. - Highlights: • This work provided a new insight into growth kinetics of Al–Fe IM thickness. • The growth kinetics of IM layer was not governed by a parabolic diffusion law. • IM near the joint interface was the origin of deviation from the parabolic law. • High stored energy at joint interface was origin of deviation from parabolic law.

• OSTI ID: 22340349
• Journal Information: Materials Characterization, Vol. 90; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
BACKSCATTERING
DIFFUSION
ELECTRON DIFFRACTION
FIELD EMISSION
IMAGE PROCESSING
INTERFACES
INTERMETALLIC COMPOUNDS
KINETICS
OPTICAL MICROSCOPES
SCANNING ELECTRON MICROSCOPY
STORED ENERGY
TRANSMISSION ELECTRON MICROSCOPY