Abstract
The transport of hydrogen during fusion welding of the titanium alloy Ti-6Al4V is analyzed. A coupled thermodynamic/kinetic treatment is proposed for the mass transport within and around the weld pool. The modeling indicates that hydrogen accumulates in the weld pool as a consequence of the thermodynamic driving forces that arise; a region of hydrogen depletion exists in cooler, surrounding regions in the heat-affected zone and beyond. Coupling with a hydrogen diffusion-controlled bubble growth model is used to simulate bubble growth in the melt and, thus, to make predictions of the hydrogen concentration barrier needed for pore formation. The effects of surface tension of liquid metal and the radius of preexisting microbubble size on the barrier are discussed. The work provides insights into the mechanism of porosity formation in titanium alloys.
| Original language | English |
|---|---|
| Pages (from-to) | 582-591 |
| Number of pages | 10 |
| Journal | Metallurgical and Materials Transactions A |
| Volume | 43 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 29 Feb 2012 |
| Externally published | Yes |
Keywords
- hydrogen
- fusion welding
- titanium alloys
- hydrogen concentration barrier
- pore formation
- surface tension
- microbubble size
- porosity formation