Additively manufactured TiAl-based composite with a multi-stage network structure synergically enabling strength and microstructural stability

To meet the increasingly complex environmental demands, titanium aluminum (TiAl) alloys need to be improved in microstructural stability and high temperature strength. However, traditional TiAl alloys exhibit poor ductility, which are incompatible with conventional manufacturing techniques such as casting and forging. Aiming to overcome these limitations, this work presents a micro/nano multiphase synergistically reinforced TiAl-based composite with optimal addition of 0.10 at.% LaB₆ via directed energy deposition, showing a homogeneously equiaxed fully lamellar. Meanwhile, the ultimate tensile strength at room temperature is 997 MPa, which is 187 MPa higher than the pure TiAl alloy (810 MPa), even at 900 °C it remains at 685 MPa that is over 100 MPa higher than the pure TiAl alloy (560 MPa). Besides, the multi-stage network structure formed by TiB and La₂O₃ precipitates significantly improves the stability of the microstructure. The present work offers an alternative solution for designing enhanced TiAl-based composites with stable microstructures via additive manufacturing.