Yao, L., Huang, S., Ramamurty, U., & Xiao, Z. (2021). On the formation of “Fish-scale” morphology with curved grain interfacial microstructures during selective laser melting of dissimilar alloys. Acta Materialia, 220, 117331. https://doi.org/10.1016/j.actamat.2021.117331
Abstract:
For successful fabrication of components using additive manufacturing techniques such
10 as powder bed fusion (PBF), directed energy deposition, and laser cladding of an alloy on to a
substrate of a dissimilar one, an interpenetrating interface morphology is essential for a good
interface strength. The physical mechanisms behind the formation of different solidified interface
morphologies after single track laser PBF of Inconel 718 powders on to the 316L austenitic
stainless stress substrate were investigated by recourse to numerical simulations, which combine
15 micron-scale fluid dynamics and solidification protocols with nanosecond-level thermal diffusion
processes. These were complemented with parametric experiments to verify the simulations.
Results show that an interface with the "fish scale" morphology can occur under certain
combinations of process parameters, and because of the combined actions of recoil pressure,
Marangoni forces, surface tension and melt pool shape. Three distinct morphologies that depend
20 on the melt pool width and depth are identified and the interfacial areas for each of them are
computed. The influence of the processing conditions that not only dictate the geometric
parameters of the melt pool but also the degree of alloying and the resulting grain morphology
within the interface microstructure were elucidated.
License type:
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
Funding Info:
This research / project is supported by the Agency for Science, Technology and Research - AME Programmatic Fund for the “Structural Metal Alloys Programme”
Grant Reference no. : A18B1b0061