A printable Nb-based alloy with remarkable high-temperature softening resistance

Additive manufacturing (AM) has the potential to revolutionize metal fabrication by enabling the creation of complex structures. However, the intrinsic high thermal stresses induced by cyclic rapid heating-and-cooling during AM often causes defects in thermal-stress-sensitive metals, hindering their printability. Conventional methods including alloying can eliminate defects and improve the printability, but often lead to deterioration in high-temperature performance. Here, we design an easily printable Nb-3W-2Mo-1Zr-0.1O alloy with exceptional high-temperature properties. The unique microstructure of our alloy, featured nanoscale deformable ZrO precipitates and subgrains, effectively mitigates thermal stresses and eliminates defects during laser-based powder bed fusion, and pins grain boundary movements during high-temperature deformation. This endows our alloy with mechanical performance comparable to commercial wrought alloys, but a sevenfold improvement in duration of work hardening showing superior high-temperature softening resistance, making it ideal for next-generation high-temperature structural applications. Our approach paves the way for manufacturing printable and high-performance thermal-stress-sensitive alloys.