Age hardening response of Cu-30Ni alloys: The role of Si microalloying additions

Kangwei Chen; Xiang Yuan Cui; Bryan Lim; Tien Tran; Andrew Duguid; Steven Camilleri; Simon P. Ringer; Keita Nomoto

doi:10.1016/j.scriptamat.2025.117056

Age hardening response of Cu-30Ni alloys: The role of Si microalloying additions

Kangwei Chen
, Xiang Yuan Cui
, Bryan Lim
, Tien Tran
, Andrew Duguid
, Steven Camilleri
, Simon P. Ringer
, Keita Nomoto

Materials for Advanced Manufacturing

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

Abstract

Cu-30Ni alloys offer high strength and excellent corrosion resistance for maritime applications. While primarily a solid solution system, industrial alloys typically include microalloying additions of Fe, Mn, Nb and/or Si to enable age hardening. However, an understanding of the microstructural evolution during age hardening remains incomplete. Here, we conduct systematic ageing treatments and report the resulting hardness and microstructures. The Cu-30Ni alloy with Si aged at 650 °C for 6 h demonstrates significantly enhanced Vickers hardness, reaching ∼201 HV₁ compared to 103 HV₁ for the as-homogenised sample. Si-rich clusters and γ′ precipitates are identified, with their composition, size, and volume fraction quantified to determine their strengthening contributions. First-principles atomistic simulations elucidate the underlying formation mechanisms of these clusters and precipitates, highlighting the critical role of Si in driving their nucleation and growth. This study advances the design of high-strength, Cu alloys with the potential for corrosion resistance in demanding maritime environments.

Original language	English
Article number	117056
Journal	Scripta Materialia
Volume	272
DOIs	https://doi.org/10.1016/j.scriptamat.2025.117056
State	Published - Feb 1 2026

Funding

Dr. Nomoto is grateful for the funding support from the Australian Research Council (ARC) Discovery Early Career Researcher Award (DE220100527). The authors acknowledge the facilities and the scientific and technical assistance of the teams at Sydney Microscopy & Microanalysis (SMM), the Sydney Informatics Hub (SIH), and the Sydney Manufacturing Hub (SMH), which are Core Research Facilities at the University of Sydney. SMM is the University of Sydney's node of Microscopy Australia (ROR: 042mm0k03)—a national research facility supported under the National Collaborative Research Infrastructure Scheme (NCRIS). This work was also partly supported by computational resources provided by the Australian Government through the National Computational Infrastructure (Gadi) under the National Computational Merit Allocation Scheme. The authors also thank Prof Sophie Primig at the University of New South Wales (UNSW) for useful discussions and providing access to the Thermo-Calc software and related support for these simulations. The contributions of Dr. Lim were supported by the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), Advanced Materials and Manufacturing Technologies Office (AMMTO) under Contract Number DE-AC05–00OR22725 with UT-Battelle LLC. The authors acknowledge gratefully Dr. Kay Song from the University of Sydney for her assistance in the preparation of this manuscript. Dr. Nomoto is grateful for the funding support from the Australian Research Council (ARC) Discovery Early Career Researcher Award ( DE220100527 ). The authors acknowledge the facilities and the scientific and technical assistance of the teams at Sydney Microscopy & Microanalysis (SMM), the Sydney Informatics Hub (SIH), and the Sydney Manufacturing Hub (SMH), which are Core Research Facilities at the University of Sydney. SMM is the University of Sydney’s node of Microscopy Australia (ROR: 042mm0k03)—a national research facility supported under the National Collaborative Research Infrastructure Scheme (NCRIS) . This work was also partly supported by computational resources provided by the Australian Government through the National Computational Infrastructure (Gadi) under the National Computational Merit Allocation Scheme . The authors also thank Prof Sophie Primig at the University of New South Wales (UNSW) for useful discussions and providing access to the Thermo-Calc software and related support for these simulations. The contributions of Dr. Lim were supported by the U.S. Department of Energy (DOE) , Office of Energy Efficiency and Renewable Energy (EERE) , Advanced Materials and Manufacturing Technologies Office (AMMTO) under Contract Number DE-AC05–00OR22725 with UT-Battelle LLC . The authors acknowledge gratefully Dr. Kay Song from the University of Sydney for her assistance in the preparation of this manuscript. This manuscript has been authored in part by UT-Battelle, LLC under Contract No DE-AC05–00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).

Keywords

Age hardening
Copper-nickel alloy
First-principles atomistic simulation
Microstructure
Precipitation

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10.1016/j.scriptamat.2025.117056

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title = "Age hardening response of Cu-30Ni alloys: The role of Si microalloying additions",

abstract = "Cu-30Ni alloys offer high strength and excellent corrosion resistance for maritime applications. While primarily a solid solution system, industrial alloys typically include microalloying additions of Fe, Mn, Nb and/or Si to enable age hardening. However, an understanding of the microstructural evolution during age hardening remains incomplete. Here, we conduct systematic ageing treatments and report the resulting hardness and microstructures. The Cu-30Ni alloy with Si aged at 650 °C for 6 h demonstrates significantly enhanced Vickers hardness, reaching ∼201 HV1 compared to 103 HV1 for the as-homogenised sample. Si-rich clusters and γ′ precipitates are identified, with their composition, size, and volume fraction quantified to determine their strengthening contributions. First-principles atomistic simulations elucidate the underlying formation mechanisms of these clusters and precipitates, highlighting the critical role of Si in driving their nucleation and growth. This study advances the design of high-strength, Cu alloys with the potential for corrosion resistance in demanding maritime environments.",

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T1 - Age hardening response of Cu-30Ni alloys

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AU - Chen, Kangwei

AU - Cui, Xiang Yuan

AU - Lim, Bryan

AU - Tran, Tien

AU - Duguid, Andrew

AU - Camilleri, Steven

AU - Ringer, Simon P.

AU - Nomoto, Keita

PY - 2026/2/1

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N2 - Cu-30Ni alloys offer high strength and excellent corrosion resistance for maritime applications. While primarily a solid solution system, industrial alloys typically include microalloying additions of Fe, Mn, Nb and/or Si to enable age hardening. However, an understanding of the microstructural evolution during age hardening remains incomplete. Here, we conduct systematic ageing treatments and report the resulting hardness and microstructures. The Cu-30Ni alloy with Si aged at 650 °C for 6 h demonstrates significantly enhanced Vickers hardness, reaching ∼201 HV1 compared to 103 HV1 for the as-homogenised sample. Si-rich clusters and γ′ precipitates are identified, with their composition, size, and volume fraction quantified to determine their strengthening contributions. First-principles atomistic simulations elucidate the underlying formation mechanisms of these clusters and precipitates, highlighting the critical role of Si in driving their nucleation and growth. This study advances the design of high-strength, Cu alloys with the potential for corrosion resistance in demanding maritime environments.

AB - Cu-30Ni alloys offer high strength and excellent corrosion resistance for maritime applications. While primarily a solid solution system, industrial alloys typically include microalloying additions of Fe, Mn, Nb and/or Si to enable age hardening. However, an understanding of the microstructural evolution during age hardening remains incomplete. Here, we conduct systematic ageing treatments and report the resulting hardness and microstructures. The Cu-30Ni alloy with Si aged at 650 °C for 6 h demonstrates significantly enhanced Vickers hardness, reaching ∼201 HV1 compared to 103 HV1 for the as-homogenised sample. Si-rich clusters and γ′ precipitates are identified, with their composition, size, and volume fraction quantified to determine their strengthening contributions. First-principles atomistic simulations elucidate the underlying formation mechanisms of these clusters and precipitates, highlighting the critical role of Si in driving their nucleation and growth. This study advances the design of high-strength, Cu alloys with the potential for corrosion resistance in demanding maritime environments.

KW - Age hardening

KW - Copper-nickel alloy

KW - First-principles atomistic simulation

KW - Microstructure

KW - Precipitation

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VL - 272

JO - Scripta Materialia

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M1 - 117056

ER -

Age hardening response of Cu-30Ni alloys: The role of Si microalloying additions

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