Pub Date : 2026-02-07DOI: 10.1016/j.actamat.2026.122001
Vadim V. Brazhkin, Oleg B. Tsiok, Andrey Tverjanovich, Takeshi Usuki, Chris J. Benmore, Maxim Khomenko, Anton Sokolov, Mohammad Kassem, Daniele Fontanari, Koji Ohara, Eugene Bychkov
{"title":"Fragile-to-strong transition in liquid As2S3 under pressure: the effect of melt metallization","authors":"Vadim V. Brazhkin, Oleg B. Tsiok, Andrey Tverjanovich, Takeshi Usuki, Chris J. Benmore, Maxim Khomenko, Anton Sokolov, Mohammad Kassem, Daniele Fontanari, Koji Ohara, Eugene Bychkov","doi":"10.1016/j.actamat.2026.122001","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.122001","url":null,"abstract":"","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"305 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-07DOI: 10.1016/j.actamat.2026.121992
Lei Fan, Zhicheng Wei, Yujia Tian, Zhenfei Jiang, Hou Yi Chia, Zixu Guo, Daijun Hu, Yang Li, Xiaoqin Zeng, Kun Zhou, Jun Ding, Tao Yang, Wentao Yan
Achieving reliable ductility while maintaining high strength in additively manufactured (AMed) multi-component alloys (MCAs) at intermediate temperatures (ITs) has remained elusive, owing to the long-standing issue of IT brittleness. In this work, Ni57-xCoxFe20Cr20Nb3 (x = 0, 19, 28.5, and 38) MCAs are produced by laser powder bed fusion to examine a valence electron concentration (VEC)-guided alloy design strategy in which Co alloying exerts a bifunctional role by concurrently tuning precipitation pathways and matrix deformability. Partial substitution of Ni with Co reduces the overall VEC of MCAs, destabilizing the incoherent and brittle D0a phase while promoting the formation of coherent L12 precipitates that remain stable even after prolonged IT annealing. Furthermore, Co reduces the stacking fault (SF) energy of the FCC matrix, thereby activating a spectrum of SF- and twin-mediated deformation modes including SFs, twins, hierarchical SF networks, and Lomer–Cottrell locks, facilitating a dynamic transition from IT brittleness to IT ductileness without sacrificing ambient-temperature performance. Consequently, the Co-rich MCA attains an ultimate tensile strength of 1032 MPa with ∼24% elongation at 973 K, accompanied by the formation of a compact protective oxide layer near the fracture surface. Such synergized effects suppress local stress intensification, sustain strain hardening, and extend plastic deformability across a wide temperature range. Overall, these findings establish bifunctional Co alloying as a broadly applicable route for overcoming IT brittleness in AMed MCAs, offering a robust design framework for next-generation structural alloys with high mechanical resilience across service-relevant temperatures.
{"title":"Taming Intermediate-Temperature Brittleness in Additively Manufactured Multi-Component Alloys via Dual-Effect Alloying","authors":"Lei Fan, Zhicheng Wei, Yujia Tian, Zhenfei Jiang, Hou Yi Chia, Zixu Guo, Daijun Hu, Yang Li, Xiaoqin Zeng, Kun Zhou, Jun Ding, Tao Yang, Wentao Yan","doi":"10.1016/j.actamat.2026.121992","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121992","url":null,"abstract":"Achieving reliable ductility while maintaining high strength in additively manufactured (AMed) multi-component alloys (MCAs) at intermediate temperatures (ITs) has remained elusive, owing to the long-standing issue of IT brittleness. In this work, Ni<sub>57-x</sub>Co<sub>x</sub>Fe<sub>20</sub>Cr<sub>20</sub>Nb<sub>3</sub> (x = 0, 19, 28.5, and 38) MCAs are produced by laser powder bed fusion to examine a valence electron concentration (VEC)-guided alloy design strategy in which Co alloying exerts a bifunctional role by concurrently tuning precipitation pathways and matrix deformability. Partial substitution of Ni with Co reduces the overall VEC of MCAs, destabilizing the incoherent and brittle D0<sub>a</sub> phase while promoting the formation of coherent L1<sub>2</sub> precipitates that remain stable even after prolonged IT annealing. Furthermore, Co reduces the stacking fault (SF) energy of the FCC matrix, thereby activating a spectrum of SF- and twin-mediated deformation modes including SFs, twins, hierarchical SF networks, and Lomer–Cottrell locks, facilitating a dynamic transition from IT brittleness to IT ductileness without sacrificing ambient-temperature performance. Consequently, the Co-rich MCA attains an ultimate tensile strength of 1032 MPa with ∼24% elongation at 973 K, accompanied by the formation of a compact protective oxide layer near the fracture surface. Such synergized effects suppress local stress intensification, sustain strain hardening, and extend plastic deformability across a wide temperature range. Overall, these findings establish bifunctional Co alloying as a broadly applicable route for overcoming IT brittleness in AMed MCAs, offering a robust design framework for next-generation structural alloys with high mechanical resilience across service-relevant temperatures.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"91 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146129479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.actamat.2026.122000
Jun Pei, Tong Zhang, Tao Liu, Yuanbiao Tong, Pan Wang, Binglun Yin, Yang Gao
Gold with the unconventional hexagonal close-packed (HCP) phase shows outstanding optical and mechanical properties, holding immense promises for optoelectronic applications. Ultrathin HCP gold films can be fabricated by reducing the thickness of the bulk face-centered cubic (FCC) precursor to a few nanometers, but the fundamental mechanism governing the thickness-dependent FCC→HCP phase transition remains insufficiently investigated. Herein, density functional theory (DFT) calculations and high-resolution transmission electron microscopy (HRTEM) are employed to elucidate the physical origin of the FCC→HCP phase transition in ultrathin gold films. DFT calculations demonstrate that in-plane compressive strain is a determining factor in facilitating the FCC→HCP phase transition, with a critical in-plane compressive strain of 2 ∼ 3% (corresponding to a lattice constant of ∼ 2.8 Å). HRTEM measurements confirm the accessibility of such compressive strain. The intrinsic compressive strain in gold thin films is approximately 1% and becomes more pronounced as the thickness decreases. The extrinsic compressive strain may arise from residual strain and substrate epitaxial strain induced during the fabrication process. Further DFT study of the kinetics of the phase transition reveals that in-plane compressive strain effectively modulates the stacking fault energy and transition pathways. Our findings establish a foundation for the structural manipulation and fabrication of advanced nanometals.
{"title":"FCC-HCP phase transition in ultrathin gold films: A first-principles investigation","authors":"Jun Pei, Tong Zhang, Tao Liu, Yuanbiao Tong, Pan Wang, Binglun Yin, Yang Gao","doi":"10.1016/j.actamat.2026.122000","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.122000","url":null,"abstract":"Gold with the unconventional hexagonal close-packed (HCP) phase shows outstanding optical and mechanical properties, holding immense promises for optoelectronic applications. Ultrathin HCP gold films can be fabricated by reducing the thickness of the bulk face-centered cubic (FCC) precursor to a few nanometers, but the fundamental mechanism governing the thickness-dependent FCC→HCP phase transition remains insufficiently investigated. Herein, density functional theory (DFT) calculations and high-resolution transmission electron microscopy (HRTEM) are employed to elucidate the physical origin of the FCC→HCP phase transition in ultrathin gold films. DFT calculations demonstrate that in-plane compressive strain is a determining factor in facilitating the FCC→HCP phase transition, with a critical in-plane compressive strain of 2 ∼ 3% (corresponding to a lattice constant of ∼ 2.8 Å). HRTEM measurements confirm the accessibility of such compressive strain. The intrinsic compressive strain in gold thin films is approximately 1% and becomes more pronounced as the thickness decreases. The extrinsic compressive strain may arise from residual strain and substrate epitaxial strain induced during the fabrication process. Further DFT study of the kinetics of the phase transition reveals that in-plane compressive strain effectively modulates the stacking fault energy and transition pathways. Our findings establish a foundation for the structural manipulation and fabrication of advanced nanometals.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"29 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146129477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.actamat.2026.121978
Alex Mamaev, Nikolas Provatas
In this paper, we employ the phase-field crystal model to examine the atomistic and diffusive behavior of lamellar precipitate colonies in binary alloys. First, we briefly review steady-state growth theories for lamellar precipitation, including the generic velocity-spacing relationships predicted for surface and volume diffusion. We next detail a novel formulation of the binary alloy structural phase-field crystal model. This includes new forms for the compositional dependence of the two-point density correlation function, which allows for robust control over the free energy and the introduction of several intermediate solid phases. We also augment the dynamics to allow for spatial variations in the mobility, allowing for control over the enhanced diffusion that occurs near grain boundaries. We perform two-dimensional numerical simulations using our model to examine lamellar precipitate growth, demonstrating agreement with steady-state theory in a time-averaged sense. We also interpret our results from a dynamic (non-steady-state) perspective by considering the roles of volume versus surface diffusion of the solute. For the case of rapid volume diffusion, we observe a large oscillatory lamellar colony velocity caused by regular, sequential buildup of coherency strain energy ahead of the grain boundary and consequent relaxation through dislocation nucleation. Conversely, for the case of surface-dominated diffusion, velocity fluctuations are more stochastic as they do not involve significant buildup of coherency strains. We end by discussing our results in the context of steady-state spacing theories and motivate the experimental relevance of our findings.
{"title":"Phase-field crystal modeling of lamellar precipitation reactions","authors":"Alex Mamaev, Nikolas Provatas","doi":"10.1016/j.actamat.2026.121978","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121978","url":null,"abstract":"In this paper, we employ the phase-field crystal model to examine the atomistic and diffusive behavior of lamellar precipitate colonies in binary alloys. First, we briefly review steady-state growth theories for lamellar precipitation, including the generic velocity-spacing relationships predicted for surface and volume diffusion. We next detail a novel formulation of the binary alloy structural phase-field crystal model. This includes new forms for the compositional dependence of the two-point density correlation function, which allows for robust control over the free energy and the introduction of several intermediate solid phases. We also augment the dynamics to allow for spatial variations in the mobility, allowing for control over the enhanced diffusion that occurs near grain boundaries. We perform two-dimensional numerical simulations using our model to examine lamellar precipitate growth, demonstrating agreement with steady-state theory in a time-averaged sense. We also interpret our results from a dynamic (non-steady-state) perspective by considering the roles of volume versus surface diffusion of the solute. For the case of rapid volume diffusion, we observe a large oscillatory lamellar colony velocity caused by regular, sequential buildup of coherency strain energy ahead of the grain boundary and consequent relaxation through dislocation nucleation. Conversely, for the case of surface-dominated diffusion, velocity fluctuations are more stochastic as they do not involve significant buildup of coherency strains. We end by discussing our results in the context of steady-state spacing theories and motivate the experimental relevance of our findings.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"30 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146129478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.actamat.2026.121986
Ismail Kamil Worke, Suman Sadhu, Saswata Bhattacharyya, Aloke Paul
A comprehensive experimental and physics-informed neural network (PINN) numerical inverse diffusion analysis is conducted on technologically important Ni-Al-Ti ternary and Ni-Co-Fe-Al-Ti quinary solid solutions to estimate and extract composition-dependent diffusion coefficients. A systematic variation of tracer, intrinsic and interdiffusion coefficients with composition could be estimated in the ternary solid solution by intersecting a ternary (in which all the elements Ni, Ti and Al produce diffusion profiles) with three pseudo-binary diffusion profiles (in which only Ti and Al produce diffusion profiles, keeping Ni constant in different compositions). The possibility of producing Al-Ti (constant Ni, Co, Fe) PB diffusion profiles in the quinary system is demonstrated. The estimation of diffusion coefficients for all elements at the Kirkendall marker plane of a single diffusion couple profile is elaborated, which is preferably produced by coupling Ni with (Ni, Co, Fe)94Al3Ti3. Following, composition-dependent diffusion coefficients are extracted using the physics-informed neural network-based optimization method, using experimentally estimated diffusion coefficients as equality constraints.
{"title":"Comprehensive Mapping of Tracer Diffusivities Across Composition Space in Ternary Ni–Al–Ti and Quinary Ni–Co–Fe–Al–Ti High-Entropy Alloy Using Diffusion Couple Experiments and Physics-Informed Neural Network Inversion","authors":"Ismail Kamil Worke, Suman Sadhu, Saswata Bhattacharyya, Aloke Paul","doi":"10.1016/j.actamat.2026.121986","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121986","url":null,"abstract":"A comprehensive experimental and physics-informed neural network (PINN) numerical inverse diffusion analysis is conducted on technologically important Ni-Al-Ti ternary and Ni-Co-Fe-Al-Ti quinary solid solutions to estimate and extract composition-dependent diffusion coefficients. A systematic variation of tracer, intrinsic and interdiffusion coefficients with composition could be estimated in the ternary solid solution by intersecting a ternary (in which all the elements Ni, Ti and Al produce diffusion profiles) with three pseudo-binary diffusion profiles (in which only Ti and Al produce diffusion profiles, keeping Ni constant in different compositions). The possibility of producing Al-Ti (constant Ni, Co, Fe) PB diffusion profiles in the quinary system is demonstrated. The estimation of diffusion coefficients for all elements at the Kirkendall marker plane of a single diffusion couple profile is elaborated, which is preferably produced by coupling Ni with (Ni, Co, Fe)<sub>94</sub>Al<sub>3</sub>Ti<sub>3</sub>. Following, composition-dependent diffusion coefficients are extracted using the physics-informed neural network-based optimization method, using experimentally estimated diffusion coefficients as equality constraints.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"83 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The crafting of lightweight and strong aluminum alloys by additive manufacturing has long relied on expensive metal elements like Sc, Zr etc. to achieve high strength, which severely hinders their widespread applications. Here we report a costly-element-free strategy that leverages the extreme thermal gradients and laser-induced recoil pressure in laser powder bed fusion (LPBF) to in situ synthesize dense and uniformly-dispersed MgAlB4 nano-whiskers within Al alloy matrix. Featuring diameters of 5-15 nm and aspect ratios exceeding 20, the nano-whiskers efficaciously eliminate solidification cracking and porosity, enabling near-full densification (∼99.99%) and an ultrafine equiaxed grain structure (∼1.3 μm). Marked dislocation-whisker interactions are enabled by the high aspect ratios of the nano-whiskers and their robust interfacial bonding with the Al matrix. Quasi-continuous nano-whisker networks in matrix not only promote dislocation storage and multiplication, but also allows for dislocation bypassing perpendicular to the axial direction of whiskers. The alloy thus achieves an ultimate tensile strength of ∼610 MPa and a uniform elongation of ∼8.0%. This work offers a scalable pathway toward the design and development of cost-effective, high-performance aluminum alloys by additive manufacturing.
{"title":"Harnessing laser-induced in-situ nanowhiskers for high-strength aluminum alloys via additive manufacturing","authors":"Haoran Yang, Xiangren Bai, Dongdong Zhao, Junwei Sha, Xudong Rong, Zehao Rong, Feng Qian, Shiwei Pan, Jianglin Lan, Xiang Zhang, Chunnian He, Naiqin Zhao","doi":"10.1016/j.actamat.2026.121987","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121987","url":null,"abstract":"The crafting of lightweight and strong aluminum alloys by additive manufacturing has long relied on expensive metal elements like Sc, Zr etc. to achieve high strength, which severely hinders their widespread applications. Here we report a costly-element-free strategy that leverages the extreme thermal gradients and laser-induced recoil pressure in laser powder bed fusion (LPBF) to in situ synthesize dense and uniformly-dispersed MgAlB<sub>4</sub> nano-whiskers within Al alloy matrix. Featuring diameters of 5-15 nm and aspect ratios exceeding 20, the nano-whiskers efficaciously eliminate solidification cracking and porosity, enabling near-full densification (∼99.99%) and an ultrafine equiaxed grain structure (∼1.3 μm). Marked dislocation-whisker interactions are enabled by the high aspect ratios of the nano-whiskers and their robust interfacial bonding with the Al matrix. Quasi-continuous nano-whisker networks in matrix not only promote dislocation storage and multiplication, but also allows for dislocation bypassing perpendicular to the axial direction of whiskers. The alloy thus achieves an ultimate tensile strength of ∼610 MPa and a uniform elongation of ∼8.0%. This work offers a scalable pathway toward the design and development of cost-effective, high-performance aluminum alloys by additive manufacturing.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"17 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146129480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.actamat.2026.121957
Ben Thornley, Maruf Sarkar, Saptarsi Ghosh, Martin Frentrup, Menno J. Kappers, Thom R. Harris-Lee, Rachel A. Oliver
Fabrication of porous GaN distributed Bragg reflectors (DBRs) via the selective electrochemical etching of conductive Si-doped layers, separated by non-intentionally doped (NID) layers, provides a straightforward methodology for producing highly reflective DBRs suitable for device overgrowth and integration, which has otherwise proven difficult in the III-nitride epitaxial system via conventional alloying. Such photonic materials can be fabricated by a lithography-free defect-driven etching process, where threading dislocations intrinsic to heteroepitaxy form nanoscale channels that facilitate etchant transport through NID layers. Here, we report the first three-dimensional characterisation of porous GaN-on-Si DBRs fabricated in this methodology with different etching voltages, using serial-section tomography in a focused ion beam scanning electron microscope (FIB-SEM). These datasets reconstruct the pore morphology as etching proliferates through the alternating Si-doped/NID layer stack. Volumetric reconstruction enabled us to enhance the established ‘kebab’ model for defect-driven etching by proposing a ‘cascade’ model where the etchant cascades through the material via vertical etching down nanopipes and horizontal etching across pores, forming complex networks directly related to the pathways taken. This accounts for premature nanopipe termination and discontinuities in nanopipe formation, where dislocations are observed to activate and deactivate individually. Statistical analysis of individual etching behaviour, across all dislocations for each tomograph, revealed a greater tendency to form continuous structures that follow conventional ‘kebab’ behaviour at higher etching voltages. We propose that higher etching voltages alter the probability of dislocation etching relative to doped layer etching, thereby empowering morphological optimization through improved mechanistic understanding of electrochemical etching.
{"title":"A cascade model for the defect-driven etching of porous GaN distributed Bragg reflectors","authors":"Ben Thornley, Maruf Sarkar, Saptarsi Ghosh, Martin Frentrup, Menno J. Kappers, Thom R. Harris-Lee, Rachel A. Oliver","doi":"10.1016/j.actamat.2026.121957","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121957","url":null,"abstract":"Fabrication of porous GaN distributed Bragg reflectors (DBRs) via the selective electrochemical etching of conductive Si-doped layers, separated by non-intentionally doped (NID) layers, provides a straightforward methodology for producing highly reflective DBRs suitable for device overgrowth and integration, which has otherwise proven difficult in the III-nitride epitaxial system via conventional alloying. Such photonic materials can be fabricated by a lithography-free defect-driven etching process, where threading dislocations intrinsic to heteroepitaxy form nanoscale channels that facilitate etchant transport through NID layers. Here, we report the first three-dimensional characterisation of porous GaN-on-Si DBRs fabricated in this methodology with different etching voltages, using serial-section tomography in a focused ion beam scanning electron microscope (FIB-SEM). These datasets reconstruct the pore morphology as etching proliferates through the alternating Si-doped/NID layer stack. Volumetric reconstruction enabled us to enhance the established ‘kebab’ model for defect-driven etching by proposing a ‘cascade’ model where the etchant cascades through the material via vertical etching down nanopipes and horizontal etching across pores, forming complex networks directly related to the pathways taken. This accounts for premature nanopipe termination and discontinuities in nanopipe formation, where dislocations are observed to activate and deactivate individually. Statistical analysis of individual etching behaviour, across all dislocations for each tomograph, revealed a greater tendency to form continuous structures that follow conventional ‘kebab’ behaviour at higher etching voltages. We propose that higher etching voltages alter the probability of dislocation etching relative to doped layer etching, thereby empowering morphological optimization through improved mechanistic understanding of electrochemical etching.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"294 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-04DOI: 10.1016/j.actamat.2026.121985
Yuval Hodaya Malinker, Shai Salhov, Malki Pinkas, Vladimir Ezersky, Olga Girshevitz, Mauricio Sortica, Johan Oscarsson, Daniel Primetzhofer, Louisa Meshi
The AlCoCrFeNi2.1 eutectic high entropy alloy (EHEA) features a dual-phase lamellar microstructure composed of ordered L1₂ and B2 phases, offering a unique combination of strength, ductility, and thermal stability. This study investigates the microstructural evolution, phase stability, and irradiation resilience of AlCoCrFeNix alloys with x = 1.9, 2.1, and 2.6. Advanced electron microscopy techniques revealed composition-dependent microstructure and confirmed the eutectic nature of the x = 2.1 alloy. Thermomechanical processing via cold rolling and annealing preserved phase ordering and enhanced mechanical properties. Irradiation of transmission electron microscopy (TEM) samples with Ne ions at doses up to 1.5 dpa enabled precise microstructure and defect analysis by comparing pre- and post-irradiation states of the same samples. The L1₂ phase exhibited dose-dependent disordering (assessed via evaluation of the fraction of 〈110〉-type dislocations), while the B2 phase retained its ordered structure, showing localized disorder and anti-phase boundaries. As a function of dose, a significant decrease in the network dislocation density (excluding dislocation loops) was observed in L12. On the other hand, this phase exhibited dose-dependent increase in both the density and size of dislocation loops. The B2 phase exhibited a similar effect, although the change was more moderate compared to L12. Semi-coherent L1₂/B2 boundaries, initially rich in dislocations, retained the Kurdjumov–Sachs orientation relationship post-irradiation, although dislocations vanished and stacking faults occasionally formed. These findings elucidate phase-specific radiation damage mechanisms and confirm the superior irradiation tolerance and structural integrity of AlCoCrFeNi2.1, highlighting its potential for nuclear structural applications.
{"title":"AlCoCrFeNi2.1 eutectic high entropy alloy: defect analysis, microstructural stability and ion irradiation resilience","authors":"Yuval Hodaya Malinker, Shai Salhov, Malki Pinkas, Vladimir Ezersky, Olga Girshevitz, Mauricio Sortica, Johan Oscarsson, Daniel Primetzhofer, Louisa Meshi","doi":"10.1016/j.actamat.2026.121985","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121985","url":null,"abstract":"The AlCoCrFeNi<sub>2.1</sub> eutectic high entropy alloy (EHEA) features a dual-phase lamellar microstructure composed of ordered L1₂ and B2 phases, offering a unique combination of strength, ductility, and thermal stability. This study investigates the microstructural evolution, phase stability, and irradiation resilience of AlCoCrFeNi<sub>x</sub> alloys with x = 1.9, 2.1, and 2.6. Advanced electron microscopy techniques revealed composition-dependent microstructure and confirmed the eutectic nature of the x = 2.1 alloy. Thermomechanical processing via cold rolling and annealing preserved phase ordering and enhanced mechanical properties. Irradiation of transmission electron microscopy (TEM) samples with Ne ions at doses up to 1.5 dpa enabled precise microstructure and defect analysis by comparing pre- and post-irradiation states of the same samples. The L1₂ phase exhibited dose-dependent disordering (assessed via evaluation of the fraction of 〈110〉-type dislocations), while the B2 phase retained its ordered structure, showing localized disorder and anti-phase boundaries. As a function of dose, a significant decrease in the network dislocation density (excluding dislocation loops) was observed in L1<sub>2</sub>. On the other hand, this phase exhibited dose-dependent increase in both the density and size of dislocation loops. The B2 phase exhibited a similar effect, although the change was more moderate compared to L1<sub>2</sub>. Semi-coherent L1₂/B2 boundaries, initially rich in dislocations, retained the Kurdjumov–Sachs orientation relationship post-irradiation, although dislocations vanished and stacking faults occasionally formed. These findings elucidate phase-specific radiation damage mechanisms and confirm the superior irradiation tolerance and structural integrity of AlCoCrFeNi<sub>2.1</sub>, highlighting its potential for nuclear structural applications.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"17 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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