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Title: Cascading microstructures in aluminum-steel interfaces created by impact welding

Abstract

With the rising need to develop light weight structures joining dissimilar metals is inevitable. Thus a fundamental understanding of the microstructure evolution and bond formation mechanism is necessary. In this work we probe the welded interface in aluminum and steel joined using vaporizing foil actuator welding (VFAW) a novel impact welding process. The goal of such a detailed characterization campaign is to understand the bond formation mechanism. The study demonstrates that the interfacial microstructure has a pronounced hierarchical nature. At the macro scale, the interface is characterized by a wavy interface which is a result of extensive plastic deformation that accompanies the process. Detailed transmission electron microscopy shows evidence for the formation of a liquid film at the interface resulting in significant inter diffusion of Fe. The solidified structure at the interface consisted of crystalline α-Al and an amorphous metastable Al-Fe intermetallic compound similar to the observations in rapid solidification of Al-Fe alloys. The sub-nm scale characterization of the interface using atom probe tomography showed two distinct zones1. A magnesium (5 at.%) and oxygen (15 at.%) rich (not detectable using energy dispersive spectroscopy) which was probably from the decomposition of the surface oxide film2. The rapidly solidified reaction zone consistingmore » of primary crystalline α-Al and an amorphous Al-Fe (15 at.%)-O (0.5 at.%)-Si (1.5 at.%).Based on these observations a mechanism for the bond formation is presented.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1];  [1]; ORCiD logo [1];  [2];  [2];  [2]
  1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
  2. The Ohio State Univ., Columbus, OH (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division; USDOE Office of Nuclear Energy (NE), Fuel Cycle Technologies (NE-5)
OSTI Identifier:
1506808
Grant/Contract Number:  
AC05-00OR22725; 0007813
Resource Type:
Accepted Manuscript
Journal Name:
Materials Characterization
Additional Journal Information:
Journal Volume: 151; Journal Issue: C; Journal ID: ISSN 1044-5803
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Sridharan, Niyanth, Poplawsky, Jonathan, Vivek, Anupam, Bhattacharya, Arunodaya, Guo, Wei, Meyer, Harry, Mao, Yu, Lee, Taeseon, and Daehn, Glenn. Cascading microstructures in aluminum-steel interfaces created by impact welding. United States: N. p., 2019. Web. doi:10.1016/j.matchar.2019.02.019.
Sridharan, Niyanth, Poplawsky, Jonathan, Vivek, Anupam, Bhattacharya, Arunodaya, Guo, Wei, Meyer, Harry, Mao, Yu, Lee, Taeseon, & Daehn, Glenn. Cascading microstructures in aluminum-steel interfaces created by impact welding. United States. doi:10.1016/j.matchar.2019.02.019.
Sridharan, Niyanth, Poplawsky, Jonathan, Vivek, Anupam, Bhattacharya, Arunodaya, Guo, Wei, Meyer, Harry, Mao, Yu, Lee, Taeseon, and Daehn, Glenn. Wed . "Cascading microstructures in aluminum-steel interfaces created by impact welding". United States. doi:10.1016/j.matchar.2019.02.019.
@article{osti_1506808,
title = {Cascading microstructures in aluminum-steel interfaces created by impact welding},
author = {Sridharan, Niyanth and Poplawsky, Jonathan and Vivek, Anupam and Bhattacharya, Arunodaya and Guo, Wei and Meyer, Harry and Mao, Yu and Lee, Taeseon and Daehn, Glenn},
abstractNote = {With the rising need to develop light weight structures joining dissimilar metals is inevitable. Thus a fundamental understanding of the microstructure evolution and bond formation mechanism is necessary. In this work we probe the welded interface in aluminum and steel joined using vaporizing foil actuator welding (VFAW) a novel impact welding process. The goal of such a detailed characterization campaign is to understand the bond formation mechanism. The study demonstrates that the interfacial microstructure has a pronounced hierarchical nature. At the macro scale, the interface is characterized by a wavy interface which is a result of extensive plastic deformation that accompanies the process. Detailed transmission electron microscopy shows evidence for the formation of a liquid film at the interface resulting in significant inter diffusion of Fe. The solidified structure at the interface consisted of crystalline α-Al and an amorphous metastable Al-Fe intermetallic compound similar to the observations in rapid solidification of Al-Fe alloys. The sub-nm scale characterization of the interface using atom probe tomography showed two distinct zones1. A magnesium (5 at.%) and oxygen (15 at.%) rich (not detectable using energy dispersive spectroscopy) which was probably from the decomposition of the surface oxide film2. The rapidly solidified reaction zone consisting of primary crystalline α-Al and an amorphous Al-Fe (15 at.%)-O (0.5 at.%)-Si (1.5 at.%).Based on these observations a mechanism for the bond formation is presented.},
doi = {10.1016/j.matchar.2019.02.019},
journal = {Materials Characterization},
number = C,
volume = 151,
place = {United States},
year = {2019},
month = {2}
}

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This content will become publicly available on February 20, 2020
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