Interface Reactions Responsible for Run-Out in Active Brazing: Part 1
Abstract
The run-out phenomenon was observed in Ag-Cu-Zr active braze joints made between the alumina ceramic and Kovar™ base material. Run-out introduces a significant yield loss by generating functional and/or cosmetic defects in brazements. A prior study identified a correlation between run-out and the aluminum (Al) released by the reduction/oxidation and the latter’s reaction with the Kovar™ base material. A study was undertaken to understand the fundamental principles of run-out by examining the interface reaction between Ag-xAl filler metals (x=2, 5, and 10 wt.%) and Kovar™ base material. Sessile drop samples were fabricated using brazing temperatures of 965°C or 995°C and times of 5 min or 20 min. The correlation was made between the degree of wetting-and-spreading by the sessile drops and the run-out phenomenon. Wetting-and-spreading increased with Al content (x) of the Ag-xAl filler metal, but was largely insensitive to the brazing process parameters. The increased Al concentration resulted in higher Al contents of the (Fe, Ni, Co)xAly reaction layer. Run-out was predicted when the filler metal has a locally-elevated, Al content exceeding 2 – 5 wt.%. Lastly, several mitigation strategies were proposed, based upon these findings.
- Authors:
-
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Publication Date:
- Research Org.:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Security
- Contributing Org.:
- American Welding Society
- OSTI Identifier:
- 1429670
- Report Number(s):
- SAND-2017-11635J
Journal ID: ISSN 0043-2296; 658200
- Grant/Contract Number:
- AC04-94AL85000; NA0003525
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Welding Journal
- Additional Journal Information:
- Journal Volume: 97; Journal Issue: 2; Journal ID: ISSN 0043-2296
- Publisher:
- American Welding Society
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE
Citation Formats
Vianco, Paul T., Walker, Charles A., De Smet, Dennis J., Kilgo, Alice C., McKenzie, Bonnie M., and Grant, Richard L. Interface Reactions Responsible for Run-Out in Active Brazing: Part 1. United States: N. p., 2018.
Web. doi:10.29391/2018.97.004.
Vianco, Paul T., Walker, Charles A., De Smet, Dennis J., Kilgo, Alice C., McKenzie, Bonnie M., & Grant, Richard L. Interface Reactions Responsible for Run-Out in Active Brazing: Part 1. United States. https://doi.org/10.29391/2018.97.004
Vianco, Paul T., Walker, Charles A., De Smet, Dennis J., Kilgo, Alice C., McKenzie, Bonnie M., and Grant, Richard L. Thu .
"Interface Reactions Responsible for Run-Out in Active Brazing: Part 1". United States. https://doi.org/10.29391/2018.97.004. https://www.osti.gov/servlets/purl/1429670.
@article{osti_1429670,
title = {Interface Reactions Responsible for Run-Out in Active Brazing: Part 1},
author = {Vianco, Paul T. and Walker, Charles A. and De Smet, Dennis J. and Kilgo, Alice C. and McKenzie, Bonnie M. and Grant, Richard L.},
abstractNote = {The run-out phenomenon was observed in Ag-Cu-Zr active braze joints made between the alumina ceramic and Kovar™ base material. Run-out introduces a significant yield loss by generating functional and/or cosmetic defects in brazements. A prior study identified a correlation between run-out and the aluminum (Al) released by the reduction/oxidation and the latter’s reaction with the Kovar™ base material. A study was undertaken to understand the fundamental principles of run-out by examining the interface reaction between Ag-xAl filler metals (x=2, 5, and 10 wt.%) and Kovar™ base material. Sessile drop samples were fabricated using brazing temperatures of 965°C or 995°C and times of 5 min or 20 min. The correlation was made between the degree of wetting-and-spreading by the sessile drops and the run-out phenomenon. Wetting-and-spreading increased with Al content (x) of the Ag-xAl filler metal, but was largely insensitive to the brazing process parameters. The increased Al concentration resulted in higher Al contents of the (Fe, Ni, Co)xAly reaction layer. Run-out was predicted when the filler metal has a locally-elevated, Al content exceeding 2 – 5 wt.%. Lastly, several mitigation strategies were proposed, based upon these findings.},
doi = {10.29391/2018.97.004},
journal = {Welding Journal},
number = 2,
volume = 97,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2018},
month = {Thu Feb 01 00:00:00 EST 2018}
}
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