Microstructural instability of L-PBF Co-28Cr-6Mo alloy at elevated temperatures

0546266 - FZÚ 2022 RIV NL eng J - Journal Article
Roudnická, Michaela - Molnárová, Orsolya - Drahokoupil, Jan - Kubásek, J. - Bigas, J. - Šreibr, V. - Paloušek, D. - Vojtěch, D.
Microstructural instability of L-PBF Co-28Cr-6Mo alloy at elevated temperatures.
Additive Manufacturing. Roč. 44, Aug. (2021), č. článku 102025. ISSN 2214-8604. E-ISSN 2214-7810
R&D Projects: GA MŠMT LM2018110
Institutional support: RVO:68378271
Keywords : Co-28Cr-6Mo * additive manufacturing * laser powder bed fusion * elevated temperature operation
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 11.632, year: 2021
Method of publishing: Limited access
https://doi.org/10.1016/j.addma.2021.102025

So far, little is known about the thermal stability of Co-28Cr-6Mo alloy when produced by laser powder bed fusion (L-PBF), one of the mostly used AM technologies. In the present study, we reveal the instability of this material already at temperatures above 673 K. Material hardening accompanied with a significant loss of plasticity is caused by the breakdown of fine cellular microstructure with intercellular Mo segregation, precipitation of σ-phase and phase transformation of the matrix. Detail characterization by transmission electron microscopy was carried out for the maximum hardness state obtained after annealing the alloy at 1173 K for 5 h. The important findings of this study, representing an operational risk for L-PBF Co-28Cr-6Mo alloy, call for subsequent research into suitable heat treatment that would induce the stability of the material.
Permanent Link: http://hdl.handle.net/11104/0322895