| About this Abstract |
| Meeting |
2024 AWS Professional Program
|
| Symposium
|
2024 AWS Professional Program
|
| Presentation Title |
Atmospheric Contamination Effects on Continuous Wave Laser Welded Ti-6Al-4V |
| Author(s) |
Jeffrey M. Rodelas, Peter G Kinney, Donald F Susan, Jack Herrmann, Austin J Pisani, Austin J Olivier |
| On-Site Speaker (Planned) |
Jeffrey M. Rodelas |
| Abstract Scope |
Despite the low heat input nature of laser welding, atmospheric contamination remains a challenge when welding titanium alloys. Local inert shielding gas delivery coaxial with the laser beam is one method of mitigating atmospheric contamination in lieu of comparatively complicated atmospheric control chambers (ex. glove box). The efficacy of local shielding gas delivery and the metallurgical implications on laser weld metal properties and interstitial contaminant species (O and N) concentration has received limited study in the technical literature with most studies focused on pulsed seam welding of commercially pure titanium. In this work, atmospheric contamination effects on continuous wave laser welded Ti-6Al-4V are evaluated. Using a custom gas mixer apparatus, the inert Ar coaxial shielding gas environment was modified to introduce controlled levels of contamination by dry air (-55°C dewpoint). Residual gas analysis was performed to quantify the composition of the gas delivered to the workpiece. As the concentration of air in the shielding gas increased, welds exhibited expected surface color changes varying from silver to gold/straw, to blue/purple, to dull gray with increasing contamination. Microhardness mapping of contaminated welds revealed increasing weld metal hardness with increasing concentration of air in the shielding gas. For severely contaminated welds (20% air), the mean hardness of resultant microhardness distributions increased 50 HVN relative to uncontaminated welds. Bulk chemical analysis (inert gas fusion) specimens will be extracted from the weld metal to quantify interstitial uptake in continuous wave laser welds. These bulk measurements will enable calibration curves to be produced for O and N that will enable quantitative mapping of interstitial contamination in continuous wave laser welds using analytical electron microscopy.
SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525 |
| Proceedings Inclusion? |
Undecided |