Rapid exploration of nanoparticle-modified alloys in metal additive manufacturing by combining inkjet printing and laser powder bed fusion

Abstract

The development of new metal alloys is key to the continued advances in critical technologies such as jet engines operating at higher temperatures, rocket engines with longer lifetime and reusability, and reactors for fusion and fission energy generation. While additive manufacturing (AM) is attractive for both prototyping and production of advanced alloys and components, the experimental screening and validation of new alloys typically requires costly synthesis of custom powder feedstocks. We present a technique for high-throughput screening of nanoparticle-enhanced alloys for AM, combining inkjet printing and laser powder bed fusion (LPBF). Alloyed specimens are prepared on metal substrates with shallow machined cavities; a nanoparticle-containing ink is printed into the cavities via inkjet deposition; powder is manually spread into the wells; and then the material is melted by scanning of a laser as in traditional LPBF. We exercise this workflow using Niobium as the base metal and with custom-formulated inks containing Si and/or Ti nanoparticles. The alloyed specimens exhibit locally defined composition, microstructure, and hardness. We demonstrate control of minority element composition of <1 % to >10 % over <1 mm distances, and along with the capability to create multi-material gradients exhibiting complex microstructural effects.