Simultaneous improvement of printability, mechanical isotropy, and high temperature strength in additively manufactured refractory multi-principal element alloy via ceramic powder additions and in-situ NbC nano-precipitation
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Simultaneous improvement of printability, mechanical isotropy, and high temperature strength in additively manufactured refractory multi-principal element alloy via ceramic powder additions and in-situ NbC nano-precipitation
Simultaneous improvement of printability, mechanical isotropy, and high temperature strength in additively manufactured refractory multi-principal element alloy via ceramic powder additions and in-situ NbC nano-precipitation
Duan, R., Zhao, Y., Li, X., Xu, J., Qin, M., Feng, K., Li, Z., Xu, B., & Ramamurty, U. (2025). Simultaneous improvement of printability, mechanical isotropy, and high temperature strength in additively manufactured refractory multi-principal element alloy via ceramic powder additions and in-situ NbC nano-precipitation. Acta Materialia, 121325. https://doi.org/10.1016/j.actamat.2025.121325
Abstract:
The inherent brittleness of the refractory multi-principal element alloys (RMPEAs) renders manufacturing of structural components with complex geometries using conventional means difficult. The additive manufacturing technique of laser powder bed fusion (LPBF) can potentially circumvent this problem. However, eliminating cracks, minimizing porosity, reducing the microstructural and (consequent) mechanical anisotropy, and retaining high-temperature (HT) strength—all simultaneously—remain the key challenges. Adding ceramic particles to the alloy can improve the printability and HT strength. However, the extreme melting points of RMPEAs can lead to their dissolution. Keeping this in view, 1.5 at.% WC powder—determined theoretically to be the optimum—was added to the Nb15Ta10W75 powders prior to LPBF. Results show an expanded process window and improved printability, attributed to the enhanced laser absorptivity, without compromising powder flowability. Carbon released through the dissolution of WC combines with Nb to form NbC in-situ, which promotes in the columnar-to-equiaxed microstructural transition and hence reduced mechanical anisotropy. The NbC nano-precipitates also enhance the high temperature strength (up to 1600 °C) by hindering the mobility of both screw and edge dislocations.
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 - Advanced Models for Additive Manufacturing
Grant Reference no. : M22L2b0111