Acta Materialia最新文献

{"title":"Cross-scale heterogeneity enables strengthening and strain de-localization in a FeMnCoCr multi-principal element alloy","authors":"H.Z. Pan ,&nbsp;S. Jiang ,&nbsp;Z.F. He ,&nbsp;X.F. Chen ,&nbsp;X.X. Dong ,&nbsp;H. Zhou ,&nbsp;N. Jia","doi":"10.1016/j.actamat.2026.121991","DOIUrl":"10.1016/j.actamat.2026.121991","url":null,"abstract":"<div><div>Heterostructure design demonstrates great potential in overcoming the strength-ductility trade-off in materials. Here, a cross-scale heterostructure was constructed in the FeMnCoCr multi-principal element alloy by performing triaxial cyclic compression (TCC) on bulk alloy followed by short-time annealing (denoted as \"Blocky\" material). For comparison, thin slices extracted from the TCC-processed block were annealed (denoted as \"Sliced\" material). At the macroscopic scale of the Blocky material, a gradient distribution of recrystallization is formed from the surface to the core. The high-strain core contains 13.3–18.1% recrystallized grains with dense dislocations, while the low-strain subcenter has less recrystallized grains (11.6–14.5%) and lower dislocation density, leading to gradient microhardness and kernel average misorientation distributions. In contrast, the Sliced material shows 20.5–24.4% recrystallization at both positions and uniform microstructure. At the grain scale, in the Blocky material non-recrystallized regions hinder plastic deformation via dense dislocation cells, local chemical order (LCO) laths, deformation twins and 9R-mediated nano-twins, while the recrystallized regions act as soft domains. At the nanoscale, extensive LCO further impedes dislocation motion. This cross-scale heterogeneity induces significant hetero-deformation-induced strengthening. The subcenter and center of the Blocky material, as well as the recrystallized/non-recrystallized domains within each region, sequentially activate deformation mechanisms. This facilitates continuous strain transfer across sample and grain scales, suppressing localized necking. Persistent activation of dislocation slip, stacking faults, nano-twins and bidirectional transformation enables the material to achieve a high yield strength of 880 MPa and an impressive fracture strain of 36%. These findings provide new insights for designing high-performance heterogeneous metallic materials.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121991"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185557","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}

{"title":"Interstitial nitrogen-engineered square-planar Ni surfaces enabling efficient hydrogenation","authors":"Yinghui Pu ,&nbsp;Yiming Niu ,&nbsp;Tongtong Gao ,&nbsp;Junnan Chen ,&nbsp;Bingsen Zhang","doi":"10.1016/j.actamat.2026.121954","DOIUrl":"10.1016/j.actamat.2026.121954","url":null,"abstract":"<div><div>Atomically precise engineering of nanocatalyst surfaces is critical for advancing heterogeneous catalysis, yet achieving both structural uniformity and electronic tunability remains challenging. Here, we report an interstitial atom-mediated strategy for constructing anti-perovskite Ni₃CuN nanocatalysts featuring square-planar Ni surfaces coordinated by nitrogen. The resulting nanoparticles adopt cubic morphologies, undergoing nitrogen-driven facet reconstruction from high-index {210}/{110} planes to thermodynamically favored {100} facets. Atomic-resolution imaging and simulations reveal that these surfaces preferentially expose Ni-N arrangements on (<span><math><mover><mn>1</mn><mo>¯</mo></mover></math></span>00) terminations, in contrast to Ni-Cu configurations on (100) facets. This well-defined surface architecture, characterized by expanded Ni-Ni distances and electron-deficient Ni sites, leads to a substantial enhancement in acetylene hydrogenation selectivity (from 25.5% to 80.1%), while maintaining or surpassing the intrinsic activity of pure Ni and exhibiting excellent stability over 110 h of testing. These findings establish an interstitial atom-based strategy for tailoring catalytic nanostructures with precise control over surface geometry and electronic structure.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121954"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146032934","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}

{"title":"Hydride precipitation stresses governing autocatalytic nucleation and stacking interaction in zirconium alloys: Phase-field modeling and HR-EBSD determination","authors":"Runhao Zhang ,&nbsp;Yao Wang ,&nbsp;Dayong An ,&nbsp;Xuchen Zhang ,&nbsp;Shuyuan Zhang ,&nbsp;Senmao Liang ,&nbsp;Hao Xiang ,&nbsp;Chao Yang ,&nbsp;Weijia Gong","doi":"10.1016/j.actamat.2026.121951","DOIUrl":"10.1016/j.actamat.2026.121951","url":null,"abstract":"<div><div>The local stress field in α-Zr matrix induced by δ-hydride precipitation is known to affect hydride microstructure, whereas the underlying mechanism remains ambiguous. This study exploits phase-field modeling of six δ-variants corresponding to potential shearing directions for the α-δ transformation to investigate influences of precipitation stresses on the nucleation and interaction behaviors of hydride platelets, in association with high angular-resolution electron backscatter diffraction (HR-EBSD) determination. Both the modeling and experimental results demonstrate that the precipitation stresses are characterized as significant concentration of triaxial tension and the <span><math><mrow><msub><mrow><mo>{</mo><mn>0001</mn><mo>}</mo></mrow><mi>α</mi></msub><msub><mrow><mo>&lt;</mo><mn>10</mn><mo>−</mo><mn>10</mn><mo>&gt;</mo></mrow><mi>α</mi></msub></mrow></math></span> shear component in the vicinity of hydride tips. This characteristic of stress distribution is further identified to promote autocatalytic nucleation and variant selection of daughter hydrides at tips of a pre-existing one. With respect to the pre-existing variant, the identical type and the opposite shearing variant exhibiting prevailing formation probabilities beyond the others, yet distinct nucleation sites due to stress gradient of the shear component. Hydride evolution simulations reveal that the identical variants stack into chain structures characterized by intermediate gaps yielding compressive stress, while the variants with opposite shear directions form intersections where the shear stress is effectively relieved. This work elucidates the governing influence of precipitation stresses on the autocatalytic nucleation and stacking interaction of hydrides, providing new insights into hydride formation mechanism in zirconium alloys.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121951"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146005937","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}

{"title":"Ice crystals under terrestrial and microgravity conditions: Experiments versus theory for tip velocity and tip radius","authors":"Dmitri V. Alexandrov ,&nbsp;Irina E. Koroznikova ,&nbsp;Alexandra E. Glebova ,&nbsp;Liubov V. Toropova","doi":"10.1016/j.actamat.2026.121959","DOIUrl":"10.1016/j.actamat.2026.121959","url":null,"abstract":"<div><div>Based on a number of experiments carried out in microgravity and terrestrial conditions, we demonstrate that the shape of ice dendrite tips sufficiently differs from an elliptical paraboloid. To describe the stable growth mode of such crystals, we apply Geometrically Morphological Theory (Acta Mater. 296 (2025), 121232), Boundary Integral Method (Physica A 469 (2017), 420) and Selection Criterion (Phys. Rep. 1085 (2024) 1). This enables us to theoretically obtain the dendrite tip velocity <span><math><mi>V</mi></math></span> and tip radius <span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> in the basal plane during the same experiment as the functions of liquid undercooling. Analyzing all available experimental data on the measurements of <span><math><mi>V</mi></math></span> and <span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>, we determined the integration limit in the heat balance equation and showed that it is close to <span><math><mrow><mn>0</mn><mo>.</mo><mn>2</mn><msub><mrow><mi>R</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></math></span> for the tips of ice crystals grown in undercooled normal and heavy water. We show that our approach corresponds to the solvability theory within the scatter of the experimental data for the selection criterion in the basal plane. In general, the developed approach describes all the experimental data in microgravity and on the ground known to us on the growth of ice crystals, where simultaneous measurements of <span><math><mi>V</mi></math></span> and <span><math><msub><mrow><mi>R</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> were performed.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121959"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034127","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}

{"title":"Confined necking and improved tensile ductility in heterostructured bi-metallic steels made by additive manufacturing","authors":"Xiao Shang ,&nbsp;Chenwei Shao ,&nbsp;Soumya S. Dash ,&nbsp;Lulu Guo ,&nbsp;Joseph Agyapong ,&nbsp;Lizhong Lang ,&nbsp;Alec Chen ,&nbsp;Sang Bum Yi ,&nbsp;Tianyi Lyu ,&nbsp;Hao Chen ,&nbsp;Solomon Boakye-Yiadom ,&nbsp;Yu Zou","doi":"10.1016/j.actamat.2026.121952","DOIUrl":"10.1016/j.actamat.2026.121952","url":null,"abstract":"<div><div>Achieving high tensile ductility is critical for structural materials, ensuring reliable load-bearing capability and adequate formability.. Steels, the most widely used structural metals, show a wide range of elongation to failure, from a few percent to a few tens of percent. Recently, heterostructured materials (HMs) have been reported to exhibit superior tensile properties that surpass those of their homogeneous counterparts. Classical HMs with heterogeneity in the length scale less than a few hundred nanometres attribute their enhanced mechanical performance mainly to the hetero-deformation induced (HDI) hardening. However, the underlying mechanisms for HMs with mesoscale heterogeneities, i.e., in the length scale of a few hundred micrometers, are overlooked. Recent advances in additive manufacturing (AM) have provided opportunities to fabricate HMs over the mesoscale range with structural complexity. In this work, we employ the AM method to fabricate a new type of mesoscale HM: bi-metallic heterostructured steels (HSs), consisting of 316L and PH17–4 stainless steels that possess distinct tensile strength and ductility. By tuning the ratios and fractions of 316L/PH17–4, we achieve 27.3%, 11.5%, and 1.8% improvements in the tensile ductility, ultimate tensile strength, and yield strength over 316L, respectively. Such enhanced tensile properties are mainly attributed to (i) confined-necking co-deformation, where the necking of PH17–4 is confined and delayed by 316L, offering more work hardening to the whole sample, (ii) switching between necking-induced and shear-induced failure modes, and (iii) the HDI hardening effect. This study paves the way for understanding and designing bi-metallic HSs with improved tensile properties using AM methods.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121952"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146006427","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}

{"title":"Tunable photocatalytic properties via layer-controlled polarization in 2D SnP2Se6/GaN heterostructures","authors":"Minglei Jia ,&nbsp;Mengyue Lan ,&nbsp;Tiexin Zhu ,&nbsp;Zhaoyang Han ,&nbsp;Chao Jin ,&nbsp;Bing Wang","doi":"10.1016/j.actamat.2026.121979","DOIUrl":"10.1016/j.actamat.2026.121979","url":null,"abstract":"<div><div>The polarization field within the heterostructure (HS) significantly affects the photocatalytic properties, especially in the separation and migration of photo-generated charge carriers. Controlling the polarization field can optimize the efficiency, selectivity, and rate of catalytic reactions, making it a key factor in designing efficient photocatalysts. This work systematically investigates the construction of SnP₂Se₆/GaN HSs with varying GaN layer thicknesses, aiming to modulate their electronic structures and photocatalytic properties. The computational results reveal that all the HSs exhibit a typical Type-II band alignment, which effectively facilitates the separation and transfer of photo-generated charge carriers, thereby significantly enhancing photocatalytic performance. In particular, when the number of GaN layers is even, a notable polarization field is induced across the HSs, resulting in a potential difference between the two sides and a corresponding shift in the band-edge positions. Further detailed investigations into the photocatalytic water splitting reaction kinetics indicate that the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance of the HSs are substantially improved compared to the individual GaN and SnP₂Se₆ components. Furthermore, by controlling the GaN layer number, the rate and selectivity of the water splitting process can be fine-tuned. This work offers novel insights and presents a promising strategy for the design of multifunctional photocatalytic materials.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121979"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110064","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}

{"title":"A dual-phase strain-transformable zirconium alloy with exceptional yield strength (1.2 GPa) and low elastic modulus (70 GPa) via TWIP and phase reversion","authors":"Junhui Tang ,&nbsp;Nicolas Jobit ,&nbsp;Agata Sotniczuk ,&nbsp;Witold Chromiński ,&nbsp;Denis Laillé ,&nbsp;Daniel Galy ,&nbsp;Philippe Vermaut ,&nbsp;Phillippe Castany ,&nbsp;Thierry Gloriant ,&nbsp;Ju Li ,&nbsp;Frédéric Prima ,&nbsp;Fan Sun","doi":"10.1016/j.actamat.2026.121966","DOIUrl":"10.1016/j.actamat.2026.121966","url":null,"abstract":"<div><div>The present study focuses on the development of a novel Zr-12Nb-3Sn alloy displaying a body-centered tetragonal (BCT) / β dual-phase microstructure and engineered to achieve a superior combination of high strength and low elastic modulus. The BCT phase is shown to play a critical role in enhancing strength without increasing elastic modulus. Comprehensive analyses using <em>in situ</em> straining electron backscatter diffraction (EBSD) experiment and transmission electron microscopy (TEM) were conducted to characterize the microstructure of the BCT phase and the associated deformation mechanisms, including dislocation slip, stress-induced reversion from BCT to β transformation, and mechanical twinning. The present findings reveal that the BCT phase and mechanical twinning both contribute to material strengthening, whereas the stress-induced reversion of the BCT phase to β acts as a mechanism for stress relaxation. As a result, the alloy demonstrates exceptional mechanical performance, achieving a yield strength exceeding 1200 MPa, an elastic modulus of approximately 70 GPa, and an elongation of ∼13%.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121966"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146047861","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}

{"title":"Fe2CrSi thin film as magnetocaloric refrigerant to liquefy/solidify high-boiling-point harmful organic substances and its associated critical phenomena","authors":"Sourav Mandal,&nbsp;Tapan Kumar Nath","doi":"10.1016/j.actamat.2026.121964","DOIUrl":"10.1016/j.actamat.2026.121964","url":null,"abstract":"<div><div>Harmful organic chemical substances require liquefaction or solidification for safe handling, but their high boiling points present significant challenges. Liquefaction of H₂ gas using the magnetocaloric response (<em>MCR</em>) near its boiling point has been proposed, highlighting the need for effective magnetic refrigerants at similar temperatures. This study introduces a potential refrigerant: a 52.4 nm thin film of half-metallic ferromagnetic (<em>HMF</em>) Full-Heusler alloy Fe₂CrSi, deposited on a single-crystalline p-type Si &lt;100&gt; wafer via electron-beam physical vapor deposition (<em>EBPVD</em>), aimed at enabling the safe handling of such substances. The thin film exhibits a continuous ‘ferromagnetic-to-paramagnetic phase transition’ above the ‘Curie temperature’ (<span><math><msub><mi>θ</mi><mrow><mi>C</mi><mi>W</mi></mrow></msub></math></span> = + 607.828 K), a ‘second-order magnetic phase transition’ (<em>SOMPT</em>). This <em>HMF</em> film possesses adequate significance for refrigeration and spintronics applications for high ‘relative cooling power’ (‘<em>RCP</em>’) of 380.85 mJ.cm^-3 (equivalent to 57.01 J.Kg^-1) at a 20 kOe field change; large ‘operating temperature range’ of 78.18 K; low constituent cost; non-toxic elements; zero thermal hysteresis; and high Curie temperature, respectively. The ‘spontaneous magnetization value close to 0 K’, <em>M_s(0)</em>, is determined to be 56.868 emu/g (∼ 1.953 <em>µ_B/f.u</em>.) by extrapolating the Arrott plot to the <em>H/M</em> = 0 axis. It is consistent with the ‘Slater-Pauling (<em>S-P</em>) rule’. Additionally, using Critical Isotherms (<em>CI</em>), ‘Rusbrooke equality’ and ‘Widom-scaling relation’, the most feasible values of its ‘critical exponents’ (<em>α</em> ≈ -1.144, <em>β</em> ≈ 0.735, <em>γ</em> ≈ 1.674 and <em>δ</em> ≈ 3.278), across the film’s <em>SOMPT</em>, are predicted.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121964"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146047863","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}

{"title":"Reaction kinetics and phase evolution of nanoporous TaC from metallic precursors","authors":"Catherine Ott ,&nbsp;Adam Peters ,&nbsp;Ian McCue","doi":"10.1016/j.actamat.2026.121980","DOIUrl":"10.1016/j.actamat.2026.121980","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121980"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","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}

{"title":"DFT-assisting experimental insights into the thermally grown oxide of thermal barrier coatings with Cr2AlC as the bond coat","authors":"Jinze Zhang ,&nbsp;Chunzhu Jiang ,&nbsp;Xiaodong He ,&nbsp;Chuchu Yang ,&nbsp;Zhiyao Lu ,&nbsp;Kebin Qin ,&nbsp;Hang Yin ,&nbsp;Yongting Zheng ,&nbsp;Guangping Song ,&nbsp;Hongming Zhang ,&nbsp;Yuelei Bai","doi":"10.1016/j.actamat.2026.121974","DOIUrl":"10.1016/j.actamat.2026.121974","url":null,"abstract":"<div><div>Because of the high oxidation resistance and appropriate coefficient of thermal expansion (CTE), Cr₂AlC has emerged as a promising bond coat (BC) for thermal barrier coatings (TBCs), but the insufficient understanding for its thermally grown oxide (TGO) and underlying mechanisms potentially hinders its practical applications. Herein, the isothermal oxidation behavior and associated TGO of TBCs with Cr₂AlC as the BC was experimentally examined at 900-1150°C with the mechanism revealed by density functional theory (DFT). Interestingly, facilitated by enhanced Al diffusivity and reactivity, a dense, continuous and nanocrystalline α-Al₂O₃-dominated TGO layer formed on top of the Cr₂AlC BC, accompanied by its decomposition into Cr₃C₂. Besides, the favorable CTE match among Cr₂AlC, Cr₃C₂, Al₂O₃ and 8YSZ ensured the TGO integrity, while it exhibited cubic oxidation kinetics, with consistently reduced thickness compared to MCrAlY. DFT simulations corroborated these experimental trends and revealed the intrinsic mechanisms: lower oxygen adsorption energy (Δ<em>E</em>_ads) on Cr₂AlC (-5.22 to -4.33 eV) versus MCrAlY (-0.94 eV). This was attributed to high oxygen affinity of Al in Cr₂AlC and inherent Al-O reactivity, promoting oxygen capture and initial nucleation of protective oxides. Moreover, cramped Cr-C interlayers were found to effectively inhibit the oxygen penetration through the (0001) surface, providing an additional mechanism for enhanced oxidation resistance of Cr₂AlC. These findings provide fundamental insights into oxidation mechanisms of the Cr₂AlC BC and offer a guidance to optimize its oxidation resistance for high-temperature applications.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121974"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072317","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}