High-temperature deformation behavior of additively manufactured niobium alloys from in-house gas-atomized feedstock

• Custom Cb752 powder was fabricated for metal additive manufacturing via in-house gas atomization, and further modified with HfC dispersions • Additively manufactured Cb752 specimens exhibited superior temperature-dependent mechanical behavior, compared to arc melted Cb752 specimens, due to stable dislocation subgrain networks • HfC additions enhanced post-yield performance by stabilizing dislocation networks and maintaining high strain hardening, resulting in superior mechanical behavior compared to both AM and arc-melted specimens. Nb-base alloys offer excellent high-temperature properties, but many legacy compositions were sidelined due to poor machinability. Additive manufacturing (AM) provides a pathway to bypass these limitations while simultaneously producing heterogeneous microstructures that can enhance performance. In this work, the legacy alloy Cb752 was gas-atomized to produce spherical powder feedstock for laser powder bed fusion, and a modified powder variant was prepared by tumbling HfC nanoparticles with the base powder. Tensile specimens were fabricated from both powders under optimized laser parameters, alongside arc-melted Cb752 for comparison. Compared to arc-melted Cb752, AM specimens exhibited consistently higher strength across 800-1600°C due to stable subgrain dislocation networks that delay recrystallization and enhance strain hardening. The HfC additions further stabilized these networks, improving post-yield performance at intermediate temperatures, though their contribution diminished after particle coarsening at 1600°C. These findings demonstrate that custom atomization and feedstock modification can unlock new performance in Nb-base alloys and provide a generalizable strategy for advancing refractory alloy systems through tailored AM processing.