Authors:
Mohammad Ibrahim (Norwegian University of Science and Technology, Norway)
Tiziano Trapletti (Norwegian University of Science and Technology, Norway)
Ragnhild Elizabeth Aune (Norwegian University of Science and Technology, Norway)
Abstract:
A functionally graded strategy was employed to address brittleness and thermal-expansion mismatches in four nickel-silicon-based alloys—NiSi11.9Co3.4, NiSi10.15V4.85, NiSi11.2Mo1.8, and NiSi10.78Ti1.84B0.1—during Directed Energy Deposition (DED) on S355 steel. Each alloy was deposited atop an Inconel 625 transition layer, producing 30?mm cylinders for structural evaluation. Except for NiSi10.78Ti1.84B0.1, all alloys printed successfully, exhibiting stable builds as they demonstrated minimal hot cracks and low porosity. Microstructural examinations using Optical Microscopy, Scanning Electron Microscopy and Energy-dispersive X-ray spectroscopy mapping showed a uniform distribution of secondary phases and grains, suggesting robust solidification conditions throughout the builds, confirming that Inconel 625 effectively mitigates residual stress and thermal mismatch issues between Nickel Silicide alloys and S355 steel. This functionally graded approach demonstrates the feasibility of DED processing for nickel-silicon-based alloys, providing a versatile solution to compositional and thermal constraints.
DOI:
https://doi.org/10.59499/EP256768149
