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}
Pub Date : 2026-02-03DOI: 10.1016/j.actamat.2026.121982
Reza Rashidi, Olivia Vaerst, Birte Riechers, Harald Rösner, Gerhard Wilde, Robert Maaß
{"title":"Atomic-scale strain fluctuations as an origin for elastic microstructures in metallic glasses","authors":"Reza Rashidi, Olivia Vaerst, Birte Riechers, Harald Rösner, Gerhard Wilde, Robert Maaß","doi":"10.1016/j.actamat.2026.121982","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121982","url":null,"abstract":"","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"253 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110041","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}
Intercalation effectively enhances the thermoelectric performance of layered semiconductors. However, conventional strategies employing a single metal element at low concentrations yield limited improvements, typically failing to achieve a zT value greater than 0.5 in intrinsic transition metal dichalcogenides (TMDCs). Here, we propose a high-entropy trace intercalation strategy by incorporating multi-component metal atoms into TiS2. Remarkably, a high thermoelectric figure of merit (zT ≈ 0.7 at 723 K) is realized, attributed to the simultaneous optimization of thermal and electronic properties: reduced total thermal conductivity κ and high power factor (PF) with enhanced weighted mobility. Key characteristics at the optimized intercalation content (x = 0.02) include minimized lattice thermal conductivity (κL), sound velocity, and elastic moduli. The outstanding performance stems from entropy-engineering, where optimized intercalation (∼2%) induces a substantial entropy enhancement by 33%, generating pronounced lattice disorder and anharmonicity. Critically, this strategy avoids the increase in κL typically associated with higher intercalant concentrations while maintaining low effective charge doping, thereby minimizing κ. Meanwhile, favorable charge transfer from the intercalation layer to the conduction layers, along with entropy-driven band renormalization, enhances the electrical transport properties. This work establishes high-entropy trace intercalation as a universal paradigm for decoupling electronic and thermal transport in layered thermoelectrics.
{"title":"High-Entropy Trace Intercalation in Layered Semiconductors: Synergistically Optimized Thermoelectric Performance via Entropy-Driven Transport Decoupling","authors":"Hongxiang Chen, Shiyu Li, Xiaochun Wen, Jing Zhang, Bing Xiao, Yunfeng Su, Hengzhong Fan, Yongsheng Zhang","doi":"10.1016/j.actamat.2026.121984","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121984","url":null,"abstract":"Intercalation effectively enhances the thermoelectric performance of layered semiconductors. However, conventional strategies employing a single metal element at low concentrations yield limited improvements, typically failing to achieve a <em>zT</em> value greater than 0.5 in intrinsic transition metal dichalcogenides (TMDCs). Here, we propose a high-entropy trace intercalation strategy by incorporating multi-component metal atoms into TiS<sub>2</sub>. Remarkably, a high thermoelectric figure of merit (<em>zT</em> ≈ 0.7 at 723 K) is realized, attributed to the simultaneous optimization of thermal and electronic properties: reduced total thermal conductivity <em>κ</em> and high power factor (<em>PF</em>) with enhanced weighted mobility. Key characteristics at the optimized intercalation content (<em>x</em> = 0.02) include minimized lattice thermal conductivity (<em>κ</em><sub>L</sub>), sound velocity, and elastic moduli. The outstanding performance stems from entropy-engineering, where optimized intercalation (∼2%) induces a substantial entropy enhancement by 33%, generating pronounced lattice disorder and anharmonicity. Critically, this strategy avoids the increase in <em>κ<sub>L</sub></em> typically associated with higher intercalant concentrations while maintaining low effective charge doping, thereby minimizing <em>κ</em>. Meanwhile, favorable charge transfer from the intercalation layer to the conduction layers, along with entropy-driven band renormalization, enhances the electrical transport properties. This work establishes high-entropy trace intercalation as a universal paradigm for decoupling electronic and thermal transport in layered thermoelectrics.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"1 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101595","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 : 2026-02-02DOI: 10.1016/j.actamat.2026.121980
Catherine Ott, Adam Peters, Ian McCue
Ultra-high temperature ceramics (UHTCs) are promising materials for use in next-generation aerospace structures but have processing challenges, particularly with respect to densification. Here, a nano-sized UHTC powder precursor was synthesized via atmospheric pressure gas-phase carburization of nanoporous tantalum to the ultra-high-temperature ceramic, TaC, at unconventionally low temperatures (700-900°C). First, a 1-D moving interface model was constructed to predict carburization depth and compare data from the present work to that in the literature, and the model was validated for finite geometries (i.e., powders). Then, the kinetic properties of Ta conversion in a carburizing environment were examined over a range of temperatures to determine rate-limiting behavior and activation energy for the process. It was found that the apparent activation energy for carburization was initially low, and conversion proceeded much faster than predicted, suggesting accelerated carbon diffusion pathways. Detailed microstructural analysis was carried out on in-house atomized powders, which did not show evidence of grain boundary diffusion. Instead, it revealed that the effects of residual strain and defects from processing may play a significant role in the carburization rates of tantalum.
{"title":"Reaction Kinetics and Phase evolution of Nanoporous TaC from Metallic Precursors","authors":"Catherine Ott, Adam Peters, Ian McCue","doi":"10.1016/j.actamat.2026.121980","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121980","url":null,"abstract":"Ultra-high temperature ceramics (UHTCs) are promising materials for use in next-generation aerospace structures but have processing challenges, particularly with respect to densification. Here, a nano-sized UHTC powder precursor was synthesized via atmospheric pressure gas-phase carburization of nanoporous tantalum to the ultra-high-temperature ceramic, TaC, at unconventionally low temperatures (700-900°C). First, a 1-D moving interface model was constructed to predict carburization depth and compare data from the present work to that in the literature, and the model was validated for finite geometries (i.e., powders). Then, the kinetic properties of Ta conversion in a carburizing environment were examined over a range of temperatures to determine rate-limiting behavior and activation energy for the process. It was found that the apparent activation energy for carburization was initially low, and conversion proceeded much faster than predicted, suggesting accelerated carbon diffusion pathways. Detailed microstructural analysis was carried out on in-house atomized powders, which did not show evidence of grain boundary diffusion. Instead, it revealed that the effects of residual strain and defects from processing may play a significant role in the carburization rates of tantalum.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"17 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110031","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 : 2026-02-02DOI: 10.1016/j.actamat.2026.121975
Phong H. Nguyen, Cong T. Bach, Huy D. Nguyen, Hoai T.L. Nguyen, Hanh H. Mai, Duy Q. Dao, Giang H. Bach
{"title":"Field-driven magnetization processes, magnetocalloric effect and tunneling magnetoconductivity in bilayer CrI 3 thin films: Insights from replica-exchange Monte Carlo simulations","authors":"Phong H. Nguyen, Cong T. Bach, Huy D. Nguyen, Hoai T.L. Nguyen, Hanh H. Mai, Duy Q. Dao, Giang H. Bach","doi":"10.1016/j.actamat.2026.121975","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121975","url":null,"abstract":"","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"8 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110065","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 : 2026-01-31DOI: 10.1016/j.actamat.2026.121977
Skye Supakul, Eda Aydogan, Mert Efe, Matthew Vigil, Bochuan Sun, Ishtiaque Robin, Kayla Yano, Wei-Ying Chen, Damian Sobieraj, Jan S. Wrόbel, Duc Nguyen-Manh, Enrique Martinez, Dan Thoma, Stuart Maloy, Osman El-Atwani
{"title":"Thermal Stability and Ion Irradiation Response of Refined Grained V – 4Cr – 4Ti","authors":"Skye Supakul, Eda Aydogan, Mert Efe, Matthew Vigil, Bochuan Sun, Ishtiaque Robin, Kayla Yano, Wei-Ying Chen, Damian Sobieraj, Jan S. Wrόbel, Duc Nguyen-Manh, Enrique Martinez, Dan Thoma, Stuart Maloy, Osman El-Atwani","doi":"10.1016/j.actamat.2026.121977","DOIUrl":"https://doi.org/10.1016/j.actamat.2026.121977","url":null,"abstract":"","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"93 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146089207","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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