Abstract
Intermetallic dispersion-strengthening (IDS) using nano-scale coherent intermetallic precipitates offers a potent strategy to produce high-strength and radiation-resistant steels, whilst addressing the manufacturability challenges of analogous oxide dispersion-strengthened (ODS) steels. However, their performance with intermetallic stability under irradiation damage, such as radiation-induced hardening (RIH), whilst hypothesised, is undemonstrated. Here, we report on a model IDS α(A2) + α’(L21) Fe-Ni-Al-Ti ferritic superalloy, which exhibits exceptional resistance to RIH with near-zero hardening after irradiation at 300 °C 1 dpa, in contrast to significant RIH in a counterpart coarse precipitate alloy (increase in nano-hardness of 1.0 GPa) and Eurofer97 (0.7 GPa). This irradiation resistance is attributed to the high density of semi-coherent precipitate-matrix interfaces, and partial-disordering L21->B2 which causes a decrease in anti-phase boundary energy. High interface density with localised interfacial strain offers effective sinks, suppressing defect populations compared to the counterpart with lower interface density. Meanwhile, atomic resolution spectroscopy and irradiation with in-situ transmission electron microscopy show that the disordering stems from Al-rich and Ti-rich sublattices mixing in the initial L21[sbnd]Ni2AlTi structure below 500 °C, forming metastable B2-Ni(Al,Ti). Combined, the high interface density and radiation-induced intermetallic disordering underpin the remarkable radiation tolerance, demonstrating the IDS concept as a promising radiation-resistant materials design strategy.
| Original language | English |
|---|---|
| Article number | 121095 |
| Journal | Acta Materialia |
| Volume | 293 |
| DOIs | |
| State | Published - Jul 1 2025 |
| Externally published | Yes |
Funding
A.J. Knowles gratefully acknowledges funding from EPSRC EP/T016566/1, UKRI Future Leaders Fellowship MR/T019174/1 & MR/Y034155/1, and Royal Academy of Engineering Research Fellowship RF\201819\18\158. A. J. Knowles, C. Hardie and S. von Tiedemann gratefully acknowledge the funding from the NEUtron iRradiatiOn of advaNced stEels (NEURONE) programme via Fusion Futures. A. J. Knowles and K. Ma thank the European Union's Horizon 2020 research and innovation programme under grant agreement No 958418 “COMPASsCO2” ( https://www.compassco2.eu ). The work at the University of Virginia was supported from the Office of Naval Research , Grant Number N00014-21-1-2477 . The atom probe facility at the University of Oxford is funded by EPSRC grant EP/T011505/1 , and access was supported by UKRI-NNUF EP/T011351/1 (Call 7 Application 88). K. Ma and A. J. Knowles thank Dr Christina Hofer and Dr Paul Bagot for their support in APT data collection, data analysis and fruitful discussion. The authors also acknowledge the Diamond Light Source UK for time on beamline I11 under proposal CY32708 , supported by Dr Sarah Day. Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 . K. Ma acknowledges the support of Dr Karen Bustillo and Dr Stephanie Ribet on the 4D-STEM experiment. K. Ma and P. A. Ferreirós acknowledge EPSRC grants EP/M028283/1 for funding the MIAMI-2 system construction and EP/X015491/1 for the UKNIBC access scheme. The authors gratefully acknowledge the Centre for Electron Microscopy University of Birmingham for their support & assistance in this work.
Keywords
- Dislocation
- Disordering
- Interface
- Intermetallic dispersion-strengthening
- Radiation-induced hardening
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