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Defect Characterization for Material Assurance in Metal Additive Manufacturing (FY15-0664)

Salzbrenner, Bradley S.; Boyce, Brad B.; Jared, Bradley H.; Rodelas, Jeffrey R.; Laing, John R.

No industry-wide standards yet exist for minimum properties in additively manufactured (AM) metals. While AM alloys such as 17-4 precipitation hardened stainless steel have been shown to have average properties that can be comparable to wrought or cast product, they suffer from inconsistent performance. Variability in the feedstock powder, feature sizes, thermal history, and laser performance can lead to unpredictable surface finish, chemistry, phase content, and defects. To address this issue, rapid, efficient, high-throughput mechanical testing and data analysis was developed, providing profound statistical insight into the stochastic variability in properties. With this new approach, 1000’s of comprehensive tensile tests can be performed for the cost of 10’s of conventional tests. This new high-throughput approach provides a material qualification pathway that is commensurate with the quick turn-around benefit of AM.

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TYPE Other Report YEAR 2016
DOIOSTI

Analysis of laser weld induced stress in a hermetic seal

Conference Proceedings of the Society for Experimental Mechanics Series

Jamison, Ryan D.; Gorman, Pierrette H.; Rodelas, Jeffrey R.; Maccallum, Danny O.; Neidigk, Matthew N.; Dempsey, James F.

Laser welding of glass-to-metal electrical connectors is a common manufacturing method for creating a hermetically sealed device. The materials in these connectors, in particular the organic glass, are sensitive to thermal induced residual stress and localized heating. An analytical laser weld model is developed that provides simulation and analysis of both thermal and mechanical effects of the welding process. Experimental studies were conducted to measure the temperature at various locations on the connector. The laser weld is modeled using both surface and volumetric heating directed along the weld path to capture the thermal and mechanical response. The weld region is modeled using an elasticplastic weld material model, which allows for compliance before welding and stiffening after the weld cools. Results from a finite element model of the glass-to-metal seal are presented and compared with experimental results. The residual compressive stress in the glass is reduced due to the welding process but hermeticity is maintained.

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TYPE Conference Poster YEAR 2016
OSTIScopus
Results 101–125 of 141
Results 101–125 of 141