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Title: Investigation of Interfacial Layer for Friction Stir Scribe Welded Aluminum to Steel Joints

Abstract

Friction stir scribe (FSS) welding as a recent derivative of friction stir welding (FSW) has been successfully used to fabricate a linear joint between automotive Al and steel sheets. It has been established that FSS welding generates a hook-like structure at the bimaterial interface. Beyond the hook-like structure, there is a lack of fundamental understanding on the bond formation mechanism during this newly developed FSS welding process. In this work, the microstructures and phases at the joint interface of FSS welded Al to ultra-high-strength steel were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that both mechanical interlocking and interfacial bonding occurred simultaneously during the FSS welding process. Based on SEM observations, a higher diffusion driving force in the advancing side was found compared to the retreating side and the scribe swept zone, and thermally activated diffusion was the primary driving force for the interfacial bond formation in the scribe swept region. The TEM energy-dispersive X-ray spectroscopy (EDXS) revealed that a thin intermetallic compound (IMC) layer was formed through the interface, where the thickness of this layer gradually decreased from the advancing side to the retreating side owing to different material plastic deformation andmore » heat generations. Finally, in addition, the diffraction pattern (or one-dimensional fast Fourier transform (FFT) pattern) revealed that the IMC layer was composed of Fe 2Al 5 or Fe 4Al 13 with a Fe/Al solid solution depending on the weld regions.« less

Authors:
 [1];  [2];  [3];  [3];  [4];  [2]
  1. Tianjin Univ. (China). Key Lab. of Mechanism Theory and Equipment Design of Ministry of Education; Pennsylvania State Univ., University Park, PA (United States). Dept. of Industrial and Manufacturing Engineering
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy Materials and Manufacturing
  3. Pennsylvania State Univ., University Park, PA (United States). Dept. of Industrial and Manufacturing Engineering
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1468165
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Manufacturing Science and Engineering
Additional Journal Information:
Journal Volume: 140; Journal Issue: 11; Journal ID: ISSN 1087-1357
Publisher:
ASME
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; friction; heat; diffusion; steel; welding; transmission electron microscopy; magnification; intermetallic compounds; scanning electron microscopy; bonding

Citation Formats

Wang, Kaifeng, Upadhyay, Piyush, Wang, Yuxiang, Li, Jingjing, Sun, Xin, and Roosendaal, Timothy. Investigation of Interfacial Layer for Friction Stir Scribe Welded Aluminum to Steel Joints. United States: N. p., 2018. Web. doi:10.1115/1.4040873.
Wang, Kaifeng, Upadhyay, Piyush, Wang, Yuxiang, Li, Jingjing, Sun, Xin, & Roosendaal, Timothy. Investigation of Interfacial Layer for Friction Stir Scribe Welded Aluminum to Steel Joints. United States. doi:10.1115/1.4040873.
Wang, Kaifeng, Upadhyay, Piyush, Wang, Yuxiang, Li, Jingjing, Sun, Xin, and Roosendaal, Timothy. Fri . "Investigation of Interfacial Layer for Friction Stir Scribe Welded Aluminum to Steel Joints". United States. doi:10.1115/1.4040873.
@article{osti_1468165,
title = {Investigation of Interfacial Layer for Friction Stir Scribe Welded Aluminum to Steel Joints},
author = {Wang, Kaifeng and Upadhyay, Piyush and Wang, Yuxiang and Li, Jingjing and Sun, Xin and Roosendaal, Timothy},
abstractNote = {Friction stir scribe (FSS) welding as a recent derivative of friction stir welding (FSW) has been successfully used to fabricate a linear joint between automotive Al and steel sheets. It has been established that FSS welding generates a hook-like structure at the bimaterial interface. Beyond the hook-like structure, there is a lack of fundamental understanding on the bond formation mechanism during this newly developed FSS welding process. In this work, the microstructures and phases at the joint interface of FSS welded Al to ultra-high-strength steel were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that both mechanical interlocking and interfacial bonding occurred simultaneously during the FSS welding process. Based on SEM observations, a higher diffusion driving force in the advancing side was found compared to the retreating side and the scribe swept zone, and thermally activated diffusion was the primary driving force for the interfacial bond formation in the scribe swept region. The TEM energy-dispersive X-ray spectroscopy (EDXS) revealed that a thin intermetallic compound (IMC) layer was formed through the interface, where the thickness of this layer gradually decreased from the advancing side to the retreating side owing to different material plastic deformation and heat generations. Finally, in addition, the diffraction pattern (or one-dimensional fast Fourier transform (FFT) pattern) revealed that the IMC layer was composed of Fe2Al5 or Fe4Al13 with a Fe/Al solid solution depending on the weld regions.},
doi = {10.1115/1.4040873},
journal = {Journal of Manufacturing Science and Engineering},
issn = {1087-1357},
number = 11,
volume = 140,
place = {United States},
year = {2018},
month = {8}
}

Journal Article:
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