About this Abstract |
| Meeting |
2025 AWS Professional Program
|
| Symposium
|
2025 AWS Professional Program
|
| Presentation Title |
Dissimilar Metal Joining of Ti-6Al-4V and 304L Stainless Steel Utilizing Cold Sprayed Interlayers |
| Author(s) |
Ethan Hopwood, Erin Barrick, Michael Kracum, Jack Herrmann, Austin Pisani |
| On-Site Speaker (Planned) |
Ethan Hopwood |
| Abstract Scope |
Dissimilar joining of Ti-6Al-4V and 304L stainless steel using a suitable cold sprayed interlayer shows potential for design flexibility by avoiding the detrimental intermetallic phases that form from direct laser welding without an interlayer. Tantalum and niobium, which are readily soluble in titanium, were chosen as the interlayer material. These refractory metals were deposited via cold spray onto a 304L stainless steel substrate and then laser butt welded to a Ti-6Al-4V coupon. Because cold spray is a solid state additive technique there is no melting between the interlayer material and the substrate which could enable the formation of intermetallic phases. Interlayers in both an “as sprayed” condition as well
as after a heat treatment were evaluated for viability. Laser welds were made in continuous wave, beam oscillation (wobble), and pulsed modes with demanded laser powers ranging from 475W to 850W. Due to the preferential melting of the lower T<sub>mp</sub> material, offsetting the laser beam up to a quarter of the beam diameter was also explored to examine the effect on the bead profile. Transverse cross sections of the welds were metallographically prepared and analyzed to understand microstructure and weld defects using optical and scanning electron microscopy. Microhardness maps across the heat affected zone and fusion zone were performed to compliment the microscopy. The welds showed no cracks and limited porosity but did show extensive asymmetry due to the disparate melting temperatures of the materials. Niobium and tantalum show promising results as an interlayer material between Ti-6Al-4V and 304L by avoiding brittle intermetallic formation when laser welded.
SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525 |
| Proceedings Inclusion? |
Undecided |