Lanthanum hexaboride as advanced structural refiner/getter in TiAl-based refractory intermetallics

Highlights
- Fist application of LaB6 additive in TiAl-based intermetallics casting.
- Pilot synthesis/casting and study of selected TiAl(Nb,Cr,Zr)B,La alloys set.
- Dual effect observed: phase structure refinement and oxygen impurity removal.
- Co-precipitation of TiB and La2O3 in melt: 2LaB6 + 12Ti + 3O → 12TiB↓ + La2O3↓.
- Features of structure refinement and oxygen gettering mechanisms reported.