About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Materials Research in Reduced Gravity
|
| Presentation Title |
Structure and Properties of the Terrestrial vs. Microgravity solders under extreme conditions of
Elevated and Cryo Temperatures
|
| Author(s) |
Manish Kumar, Samuel O. Falana, Sid Pathak |
| On-Site Speaker (Planned) |
Samuel O. Falana |
| Abstract Scope |
We report results from the microstructural characterization and micromechanical response of terrestrial versus microgravity solders under extreme cryogenic and elevated temperatures, and thermal cycling conditions mimicking space exploration (–157ºC to +121ºC outside the ISS). Using 3D tomography and SEM, we characterized 40Pb-60Sn solders produced on Earth and aboard the ISS. Microgravity samples showed distinct void distribution and dendritic structures, compared to terrestrial samples, indicating the absence of buoyancy and the dominance of Marangoni and surface tension flow during solidification.
Under cryogenic conditions, we examine the effects of β-to-α phase transformation in Sn below 13ºC, associated volume and internal stress changes, and ductile to brittle transition (DBT) in various Sn-based solders. Evidence of DBT in eutectic and off-eutectic Pb-Sn, and 95.5Sn-3.8Ag-0.7Cu solders was observed from in-situ SEM micropillar experiments. These results demonstrate lower plastic strain at instability, higher yield strength, and higher instability stress at cryo temperatures compared to RT. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Joining, Solidification, Other |