Evolution of eutectic microstructure and strength in an Al-Ce-Ni-Mn-Sc-Zr alloy fabricated by laser powder-bed fusion

Clement N. Ekaputra; Jon Erik Mogonye; David C. Dunand

doi:10.1016/j.addma.2025.104903

Evolution of eutectic microstructure and strength in an Al-Ce-Ni-Mn-Sc-Zr alloy fabricated by laser powder-bed fusion

Clement N. Ekaputra, Jon Erik Mogonye, David C. Dunand

Alloy Behavior & Design

Research output: Contribution to journal › Article › peer-review

Abstract

We characterize the evolution of microstructure and mechanical properties during thermal exposure of a strong and creep-resistant Al-11.5Ce-3.4Ni-0.6Mn-0.11Sc-0.34Zr (wt%) alloy fabricated by laser power-bed fusion (L-PBF). The alloy composition is based on a cast, near-eutectic alloy (Al-10.4Ce-3.5Ni-0.80Mn-0.25Sc-0.12Zr, wt%) with extreme creep- and coarsening-resistance for high-temperature applications. The as-fabricated L-PBF alloy exhibits a continuous network of fine, eutectic Al₁₁Ce₃ and Al₂₇Ce₃Ni₆ phases. The compositions of these phases are non-stoichiometric in the peak-aged alloy, but shift to the stoichiometric compositions during long-term thermal exposure. Upon aging at 300–400°C, L1₂-Al₃(Sc,Zr) nanoprecipitates form in the α-Al matrix and at the matrix/eutectic interface; Mn solutes are present in the Al matrix, but to a lesser extent than in the cast alloy. The refined eutectic phases are the dominant strengthening mechanism in the L-PBF alloy, and their evolution controls the loss of strength and creep resistance at elevated temperatures. During long-term thermal exposure at 300–400°C, the continuous eutectic network fragments into discontinuous elongated particles, which then spheroidize and coarsen. The initial eutectic fragmentation is associated with a significant decrease in room-temperature hardness and work-hardening capacity; the subsequent particle coarsening is slower and results in a more gradual decline in room-temperature strength and hardness. At 300°C, the alloy demonstrates excellent creep resistance, with dislocation creep threshold stresses of 109–149 MPa, depending on the aging condition and eutectic microstructure. Lastly, we demonstrate via analytical and numerical (finite-element) modelling that inhibition of dislocation motion, rather than load transfer, is the dominant strengthening mechanism imparted by the eutectic precipitates.

Original language	English
Article number	104903
Journal	Additive Manufacturing
Volume	109
DOIs	https://doi.org/10.1016/j.addma.2025.104903
State	Published - Jul 5 2025

Funding

CNE thanks Dr. Tiffany Wu for training in finite-element modeling, and Dr. Dieter Isheim for assistance in analyzing atom-probe tomography data. CNE was supported by the DEVCOM Army Research Laboratory (ARL) Research Associateship Program (RAP). Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-20–2–0292 and W911NF-21–2–02199. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory of the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. This work made use of the MatCI Facility which receives support from the MRSEC Program (NSF DMR-2308691) of the Materials Research Center at Northwestern University. This work made use of the CLaMMP Facility which receives support from the MRSEC Program (NSF DMR-2308691) of the Materials Research Center at Northwestern University. This work made use of the EPIC facility of Northwestern University's NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern's MRSEC program (NSF DMR-2308691). Atom-probe tomography was performed at the Northwestern University Center for Atom-Probe Tomography (NUCAPT). The LEAP tomograph at NUCAPT was purchased and upgraded with grants from the NSF-MRI (DMR-0420532) and ONR-DURIP (N00014–0400798, N00014–0610539, N00014–0910781, N00014–1712870) programs. NUCAPT received support from the MRSEC program (NSF DMR-1720139) at the Materials Research Center, the SHyNE Resource (NSF ECCS-1542205), and the Initiative for Sustainability and Energy (ISEN) at Northwestern University. This work made use of the Jerome B.Cohen X-Ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-2308691) at the Materials Research Center of Northwestern University and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-2025633.) This work made use of the MatCI Facility which receives support from the MRSEC Program (NSF DMR-2308691) of the Materials Research Center at Northwestern University. This work made use of the CLaMMP Facility which receives support from the MRSEC Program ( NSF DMR-2308691 ) of the Materials Research Center at Northwestern University . This work made use of the EPIC facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource ( NSF ECCS-2025633 ), the IIN, and Northwestern's MRSEC program (NSF DMR-2308691 ). Atom-probe tomography was performed at the Northwestern University Center for Atom-Probe Tomography ( NUCAPT ). The LEAP tomograph at NUCAPT was purchased and upgraded with grants from the NSF-MRI ( DMR-0420532 ) and ONR-DURIP ( N00014–0400798 , N00014–0610539 , N00014–0910781 , N00014–1712870 ) programs. NUCAPT received support from the MRSEC program (NSF DMR-1720139 ) at the Materials Research Center, the SHyNE Resource (NSF ECCS-1542205 ), and the Initiative for Sustainability and Energy (ISEN) at Northwestern University. This work made use of the Jerome B.Cohen X-Ray Diffraction Facility supported by the MRSEC program of the National Science Foundation ( DMR-2308691 ) at the Materials Research Center of Northwestern University and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-2025633 .) CNE thanks Dr. Tiffany Wu for training in finite-element modeling, and Dr. Dieter Isheim for assistance in analyzing atom-probe tomography data. CNE was supported by the DEVCOM Army Research Laboratory (ARL) Research Associateship Program (RAP). Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-20–2–0292 and W911NF-21–2–02199 . The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory of the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein.

Keywords

Aluminum alloys
Eutectic
Laser powder bed, fusion
Mechanical properties
Microstructure

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10.1016/j.addma.2025.104903

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title = "Evolution of eutectic microstructure and strength in an Al-Ce-Ni-Mn-Sc-Zr alloy fabricated by laser powder-bed fusion",

abstract = "We characterize the evolution of microstructure and mechanical properties during thermal exposure of a strong and creep-resistant Al-11.5Ce-3.4Ni-0.6Mn-0.11Sc-0.34Zr (wt\%) alloy fabricated by laser power-bed fusion (L-PBF). The alloy composition is based on a cast, near-eutectic alloy (Al-10.4Ce-3.5Ni-0.80Mn-0.25Sc-0.12Zr, wt\%) with extreme creep- and coarsening-resistance for high-temperature applications. The as-fabricated L-PBF alloy exhibits a continuous network of fine, eutectic Al11Ce3 and Al27Ce3Ni6 phases. The compositions of these phases are non-stoichiometric in the peak-aged alloy, but shift to the stoichiometric compositions during long-term thermal exposure. Upon aging at 300–400°C, L12-Al3(Sc,Zr) nanoprecipitates form in the α-Al matrix and at the matrix/eutectic interface; Mn solutes are present in the Al matrix, but to a lesser extent than in the cast alloy. The refined eutectic phases are the dominant strengthening mechanism in the L-PBF alloy, and their evolution controls the loss of strength and creep resistance at elevated temperatures. During long-term thermal exposure at 300–400°C, the continuous eutectic network fragments into discontinuous elongated particles, which then spheroidize and coarsen. The initial eutectic fragmentation is associated with a significant decrease in room-temperature hardness and work-hardening capacity; the subsequent particle coarsening is slower and results in a more gradual decline in room-temperature strength and hardness. At 300°C, the alloy demonstrates excellent creep resistance, with dislocation creep threshold stresses of 109–149 MPa, depending on the aging condition and eutectic microstructure. Lastly, we demonstrate via analytical and numerical (finite-element) modelling that inhibition of dislocation motion, rather than load transfer, is the dominant strengthening mechanism imparted by the eutectic precipitates.",

keywords = "Aluminum alloys, Eutectic, Laser powder bed, fusion, Mechanical properties, Microstructure",

author = "Ekaputra, \{Clement N.\} and Mogonye, \{Jon Erik\} and Dunand, \{David C.\}",

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year = "2025",

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doi = "10.1016/j.addma.2025.104903",

language = "English",

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T1 - Evolution of eutectic microstructure and strength in an Al-Ce-Ni-Mn-Sc-Zr alloy fabricated by laser powder-bed fusion

AU - Ekaputra, Clement N.

AU - Mogonye, Jon Erik

AU - Dunand, David C.

PY - 2025/7/5

Y1 - 2025/7/5

N2 - We characterize the evolution of microstructure and mechanical properties during thermal exposure of a strong and creep-resistant Al-11.5Ce-3.4Ni-0.6Mn-0.11Sc-0.34Zr (wt%) alloy fabricated by laser power-bed fusion (L-PBF). The alloy composition is based on a cast, near-eutectic alloy (Al-10.4Ce-3.5Ni-0.80Mn-0.25Sc-0.12Zr, wt%) with extreme creep- and coarsening-resistance for high-temperature applications. The as-fabricated L-PBF alloy exhibits a continuous network of fine, eutectic Al11Ce3 and Al27Ce3Ni6 phases. The compositions of these phases are non-stoichiometric in the peak-aged alloy, but shift to the stoichiometric compositions during long-term thermal exposure. Upon aging at 300–400°C, L12-Al3(Sc,Zr) nanoprecipitates form in the α-Al matrix and at the matrix/eutectic interface; Mn solutes are present in the Al matrix, but to a lesser extent than in the cast alloy. The refined eutectic phases are the dominant strengthening mechanism in the L-PBF alloy, and their evolution controls the loss of strength and creep resistance at elevated temperatures. During long-term thermal exposure at 300–400°C, the continuous eutectic network fragments into discontinuous elongated particles, which then spheroidize and coarsen. The initial eutectic fragmentation is associated with a significant decrease in room-temperature hardness and work-hardening capacity; the subsequent particle coarsening is slower and results in a more gradual decline in room-temperature strength and hardness. At 300°C, the alloy demonstrates excellent creep resistance, with dislocation creep threshold stresses of 109–149 MPa, depending on the aging condition and eutectic microstructure. Lastly, we demonstrate via analytical and numerical (finite-element) modelling that inhibition of dislocation motion, rather than load transfer, is the dominant strengthening mechanism imparted by the eutectic precipitates.

AB - We characterize the evolution of microstructure and mechanical properties during thermal exposure of a strong and creep-resistant Al-11.5Ce-3.4Ni-0.6Mn-0.11Sc-0.34Zr (wt%) alloy fabricated by laser power-bed fusion (L-PBF). The alloy composition is based on a cast, near-eutectic alloy (Al-10.4Ce-3.5Ni-0.80Mn-0.25Sc-0.12Zr, wt%) with extreme creep- and coarsening-resistance for high-temperature applications. The as-fabricated L-PBF alloy exhibits a continuous network of fine, eutectic Al11Ce3 and Al27Ce3Ni6 phases. The compositions of these phases are non-stoichiometric in the peak-aged alloy, but shift to the stoichiometric compositions during long-term thermal exposure. Upon aging at 300–400°C, L12-Al3(Sc,Zr) nanoprecipitates form in the α-Al matrix and at the matrix/eutectic interface; Mn solutes are present in the Al matrix, but to a lesser extent than in the cast alloy. The refined eutectic phases are the dominant strengthening mechanism in the L-PBF alloy, and their evolution controls the loss of strength and creep resistance at elevated temperatures. During long-term thermal exposure at 300–400°C, the continuous eutectic network fragments into discontinuous elongated particles, which then spheroidize and coarsen. The initial eutectic fragmentation is associated with a significant decrease in room-temperature hardness and work-hardening capacity; the subsequent particle coarsening is slower and results in a more gradual decline in room-temperature strength and hardness. At 300°C, the alloy demonstrates excellent creep resistance, with dislocation creep threshold stresses of 109–149 MPa, depending on the aging condition and eutectic microstructure. Lastly, we demonstrate via analytical and numerical (finite-element) modelling that inhibition of dislocation motion, rather than load transfer, is the dominant strengthening mechanism imparted by the eutectic precipitates.

KW - Aluminum alloys

KW - Eutectic

KW - Laser powder bed, fusion

KW - Mechanical properties

KW - Microstructure

UR - https://www.scopus.com/pages/publications/105011737259

U2 - 10.1016/j.addma.2025.104903

DO - 10.1016/j.addma.2025.104903

M3 - Article

AN - SCOPUS:105011737259

SN - 2214-8604

VL - 109

JO - Additive Manufacturing

JF - Additive Manufacturing

M1 - 104903

ER -

Evolution of eutectic microstructure and strength in an Al-Ce-Ni-Mn-Sc-Zr alloy fabricated by laser powder-bed fusion

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