Effect of nitrogen atmosphere on the printability, microstructure, precipitation, and mechanical properties of laser powder bed fused Fe-xCr alloys

Effect of nitrogen atmosphere on the printability, microstructure, precipitation, and mechanical properties of laser powder bed fused Fe-xCr alloys

Additive Manufacturing

10.1016/j.addma.2024.104077

http://dx.doi.org/10.1016/j.addma.2024.104077

Siyuan Wei, Delvin Wuu, Verner Soh, Kwang Boon Lau, Fengxia Wei, Konstantinos A. Liogas, Baicheng Zhang, Qiang Zhu, Chee Koon Ng, Alexander M. Korsunsky, Pei Wang, Upadrasta Ramamurty

12 March 2024

Wei, S., Wuu, D., Soh, V., Lau, K. B., Wei, F., Liogas, K. A., Zhang, B., Zhu, Q., Ng, C. K., Korsunsky, A. M., Wang, P., & Ramamurty, U. (2024). Effect of nitrogen atmosphere on the printability, microstructure, precipitation, and mechanical properties of laser powder bed fused Fe-xCr alloys. Additive Manufacturing, 83, 104077. https://doi.org/10.1016/j.addma.2024.104077

The role of the nitrogen atmosphere on the microstructure and tensile properties of laser powder bed fused (PBF-LB/M) Fe-xCr (x=0, 5, 10, 15, 24 wt.%, mixed using elemental Fe and pre-alloyed Fe-46 wt.% Cr powders) binary alloys was investigated and compared with those fabricated under an inert (argon) atmosphere. Microstructural characterization reveals the variations of grain morphology with the chemical composition and the distinct effects of nitrogen on grain refinement and texture. Additionally, PBF-LB/M performed under the nitrogen atmosphere leads to the formation of Cr and Fe nitrides in the alloy. Significant enhancements in strength were observed in Fe, Fe-5Cr, and Fe-10Cr fabricated under nitrogen atmosphere due possibly to the solid solution and precipitation strengthening caused by dissolved nitrogen and the nitrides, respectively. However, the Fe-15Cr and Fe-24Cr alloys processed under the nitrogen atmosphere are brittle and crack upon PBF-LB/M due to the residual stresses. The findings in this work enrich the understanding of the effects of fabrication atmospheres in additive manufacturing, insights of which can be extended to diverse categories of alloys.

Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

This research / project is supported by the A*STAR - Structural Metal Alloys Programme
Grant Reference no. : A18B1b0061

This research / project is supported by the A*STAR - Individual Research Grant
Grant Reference no. : A20E7c0109

https://oar.a-star.edu.sg/communities-collections/articles/20386

2214-8604

Institute of Materials Research & Engineering