Process Robustness of Friction Stir Dovetailing of AA7099 to Steel with In Situ AA6061 Interlayer Linking

Conference · Wed Feb 17 04:00:00 EST 2021

OSTI ID:1782477

Reza E Rabby, MD ^[1]; Roosendaal, Timothy J. ^[1]; Upadhyay, Piyush ^[1]; Overman, Nicole R. ^[1]; Silverstein, Joshua A. ^[1]; Mcdonnell, Martin ^[2]; Whalen, Scott A. ^[1]

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1. BATTELLE (PACIFIC NW LAB)
2. U.S. Army Tank Automotive Research, Development and Engineering Center

Rolled homogeneous armor (RHA) steel was joined to aluminum alloy AA7099-T7451 with an interlayer of AA6061-T651 by single-pass friction stir dovetailing (FSD). The evolution of the AA7099/AA6061 and AA6061/steel interfacial microstructures and mechanical properties of the joints were examined. The AA6061 interlayer prevented Zn migration from the AA7099 to the steel during FSD and inhibited formation of brittle, Zn-rich, Fe-Al intermetallic compounds within the joint. The flow of the dissimilar aluminum alloys at the interface was controlled with a partially threaded friction stir welding pin and a dovetail geometric configuration optimized in previous work. The process robustness was explored to establish parameter windows by elucidating parametric effects on the relationship between process conditions and the joint’s microstructure and mechanical properties. Ranges of process forge force (50–70 kN) and interface temperature (475°C–515°C) consistently yielded joints with adequate performance. The load-carrying capacity in lap shear tensile tests was 2025 ? 100 N/mm.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1782477
• Report Number(s): PNNL-SA-155938
• Country of Publication: Switzerland
• Language: English

Related Subjects

Friction Stir Dovetailing
FSW
AA7099
AA6061
Rolled homogenous armor
RHA