Effect of powder milling on sintering behavior and monotonic and cyclic mechanical properties of Mo and Mo–Si lattices produced by direct ink writing

• Published in: Journal of materials research and technology Vol. 27; pp. 2475 - 2489
• Main Authors: Tkachenko, Serhii, Slámečka, Karel, Oliver-Urrutia, Carolina, Ksenzova, Olha, Bednaříková, Vendula, Remešová, Michaela, Dvořák, Karel, Baláž, Matej, Deák, Andrea, Kachlík, Martin, Čelko, Ladislav, Montufar, Edgar B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2023; Elsevier
• Subjects: Cyclic compression test; Metallic matrix composite; Molybdenum; Porous structure; Robocasting; Silicon; Robocasting; Cyclic compression test; Porous structure; Silicon; Molybdenum; Metallic matrix composite
• ISSN: 2238-7854
• DOI: 10.1016/j.jmrt.2023.10.002

Molybdenum is a refractory metal regarded as a promising basis for producing high-temperature components. However, the potential of manufacturing molybdenum-based structures by direct ink writing (DIW) has not been explored. In this study, three-dimensional porous molybdenum (Mo) and molybdenum-silicon (Mo–Si) composite lattices were fabricated using DIW with non-milled and milled powders. The effects of Mo powder morphology (resulting from milling) and chemical composition (alloying Mo with 3 and 10 wt% of Si) on the microstructure, phase composition, and static and cyclic compression properties at room temperature were investigated. Lattices fabricated from commercial spherical Mo powder exhibited the highest intra-filament porosity. Conversely, lattices fabricated from milled Mo powder were denser and had higher compressive strength, offset stress, and quasi-elastic gradient. Alloying Mo with Si during sintering resulted in composite lattices with Mo + Mo3Si microstructure. A low content of Mo3Si slightly decreased monotonic compression properties but did not affect the cyclic compression response compared to Mo lattices made from milled powder. In contrast, a high content of Mo3Si produced quasi-brittle lattices with reduced compressive strength and increased damage accumulation during cyclic loading. The cyclic behavior of all lattices was characterized by a ratcheting-dominated stress-strain response. Lattices fabricated from milled Mo and milled Mo-3 wt.%Si powders demonstrated superior performance compared to those fabricated from commercial spherical Mo and milled Mo-10 wt%Si powders. The results suggest that using milled powders can enhance the mechanical reliability and promote the use of DIW as preferred additive manufacturing technology for the fabrication of Mo–Si composite lattices. •Mo and Mo-Si powders were used to fabricate refractory lattices by direct ink writing.•Powder milling improves the monotonic and cyclic mechanical reliability of lattices.•Si alloying creates Mo matrix composite lattices reinforced in situ with Mo3Si.•Low Si slightly decreases the monotonic strength but not the cyclic properties.•High Si produces quasi-brittle lattices that accumulate more damage in cyclic loading.