Materialia最新文献

{"title":"Local variation of element concentrations in a NPLE based austenite to ferrite phase transformation model","authors":"Bernhard Bloder ,&nbsp;Christian Hoflehner ,&nbsp;Markus Sonnleitner ,&nbsp;Peter Raninger ,&nbsp;Thomas Antretter","doi":"10.1016/j.mtla.2025.102532","DOIUrl":"10.1016/j.mtla.2025.102532","url":null,"abstract":"<div><div>In this work we present an austenite to ferrite phase transformation model based on local equilibrium with negligible partitioning for steels for which manganese is the thermodynamically dominant substitutional alloying element. By introducing some simplifications, the diffusion controlled transformation can be calculated with comparatively low computational costs. Besides geometrical effects and nucleation, local variation of element concentration is also taken into account, which improves the prediction quality. Segregation effects are estimated by electron microprobe analyzer measurements and compared to thermodynamic calculations. The model is first tested on four model alloys, then on a large number of alloys with a composition close to industrial steel grades.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102532"},"PeriodicalIF":2.9,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanism of porous tungsten nanostructure formation by pulsed laser deposition","authors":"Shin Kajita ,&nbsp;Shogo Kodate ,&nbsp;Shunsuke Kato ,&nbsp;Quan Shi ,&nbsp;Yuki Hayashi","doi":"10.1016/j.mtla.2025.102529","DOIUrl":"10.1016/j.mtla.2025.102529","url":null,"abstract":"<div><div>Pulsed laser deposition (PLD) is a technique that allows the formation of thin films on various materials. In this study, we focused on metal tungsten thin film formed via PLD under relatively high argon pressure (50 and 100 Pa). It is shown that porous nanostructured thin films can be formed by controlling the background gas pressure and the distance between the ablation target and the substrate. To demonstrate the formation process, three-dimensional Monte Carlo particle simulation is performed by introducing directional motion and surface adhesion probability to randomly diffusing particles. It is discussed that the porous structures are formed with a top-down process, and the diffusion-limited aggregation (DLA) process likely governs the formation of porous structures.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"43 ","pages":"Article 102529"},"PeriodicalIF":2.9,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient compositional exploration for sluggish interstitial diffusion in FeNiCrCoCu high-entropy alloys using machine learning-kinetic Monte Carlo and Bayesian optimization","authors":"Wenjiang Huang,&nbsp;Xian-Ming Bai","doi":"10.1016/j.mtla.2025.102531","DOIUrl":"10.1016/j.mtla.2025.102531","url":null,"abstract":"<div><div>The study of sluggish diffusion in high-entropy alloys (HEAs) remains underexplored largely due to their extensive compositional space. In particular, self-interstitial diffusion exhibits a non-monotonic compositional dependence, necessitating an efficient search to identify optimum compositions. This work presents three kinetic Monte Carlo (KMC)-based methods to simulate complex <span><math><mrow><mo>〈</mo><mn>100</mn><mo>〉</mo></mrow></math></span> interstitial dumbbell diffusion of 15 dumbbell types with 125 distinct migration paths in a model FeNiCrCoCu HEA system over a large compositional space: conventional KMC (C-KMC), random-sampling KMC (RS-KMC), and machine learning KMC (ML-KMC). Our results demonstrate that ML-KMC, with its ability of efficiently predicting dumbbell formation energies on the fly, can effectively capture key diffusion patterns, as validated by independent molecular dynamics (MD) simulations. This ML-KMC method provides a promising high-throughput approach (about 3500 times faster than MD) for studying the complex dumbbell diffusion in HEAs. The controversial percolation effect by faster diffusing elements (Cr+Cu) is also analyzed, suggesting no universal percolation threshold in HEAs. To efficiently explore the compositional space and pinpoint HEA compositions with slower interstitial diffusivities, ML-KMC is integrated within a Bayesian optimization (BO) framework. This approach successfully identifies HEA compositions with diffusivities over an order of magnitude slower than the equiatomic HEA at 800 K within only a few ten iterations, circumventing the inefficiency of conventional brute-force compositional enumeration. The identified optimal composition (Fe₃₅Ni₁₄Cr₆Co₃₅Cu₁₀) is further verified by independent MD simulations, confirming the effectiveness of the ML-KMC-BO methodology. This work can advance the understanding of compositional-dependent diffusion mechanisms and provide valuable insights for HEA design.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"43 ","pages":"Article 102531"},"PeriodicalIF":2.9,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strain-driven phase transformation and carbon segregation in carbide free nano-bainitic steel under sliding wear","authors":"Sudharm Rathore ,&nbsp;Kritika Singh ,&nbsp;Aparna Singh","doi":"10.1016/j.mtla.2025.102535","DOIUrl":"10.1016/j.mtla.2025.102535","url":null,"abstract":"<div><div>Carbide free nano-bainitic steel was made by austenitizing and subsequent austempering a high carbon steel at 250°C and 350°C. Uni-directional sliding using conical indenter (CI) as well as reciprocating sliding using spherical indenter (SI) was carried out. The subsurface deformation was compared between these processes using transmission electron microscopy (TEM) and atom probe tomography (APT) while finite element computations were used to find the equivalent plastic strain and shear stress. There were distinct differences in carbon segregation and microstructural evolution signifying the critical role of the nature of sliding friction. The CI samples showed carbon segregation just below the indenter within the deformed zone and complete transformation of retained austenite to mostly twinned martensite for 350°C austempered sample and partial transformation for 250°C austempered sample. Whereas both SI samples show uniform distribution of carbon within the deformed zone as well as complete transformation of retained austenite to martensite.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"43 ","pages":"Article 102535"},"PeriodicalIF":2.9,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-eutectic versus eutectic borides in a boride-ferrite composite: Differences in microchemistry, microtexture, and residual stress","authors":"Akhil G. Nair ,&nbsp;Namit Pai ,&nbsp;Chanchal Ghosh ,&nbsp;Indradev Samajdar ,&nbsp;Arup Dasgupta","doi":"10.1016/j.mtla.2025.102534","DOIUrl":"10.1016/j.mtla.2025.102534","url":null,"abstract":"<div><div>This study involved as-cast, albeit heat-treated, boron-containing 9Cr-1Mo steel, which resulted in various composites of bcc-ferrite (α-Fe) and boride ((Fe,Cr)₂B) phases. The heat treatments, normalizing and tempering, were necessary to reduce composite embrittlement. However, they did not significantly alter phase-specific microchemistry, microtexture, and residual stress. An increase in boron content (0.5 and 2.5 to 5 wt%) enhanced, as expected, boride presence. In the lower boron-containing specimens, fine (∼1 μm) post-solidification eutectic borides were observed. Material with 5 wt% boron, on the other hand, contained larger (∼23 μm) non-eutectic and smaller (∼1 μm) eutectic borides in almost equal volume fractions. An increase in boron content thus transformed a metal-matrix composite with ceramic reinforcement (0.5 and 2.5 wt% boron) into a ceramic-matrix composite with a metallic second phase (5 wt% boron). This study extensively used analytical microscopy, particularly multiscale diffraction-based microtexture and residual stress measurements, to differentiate between eutectic and non-eutectic borides. The non-eutectic borides had a morphological alignment typical of directional solidification. They also exhibited faceted and non-faceted interfaces, the former representing a sharper composition gradient. Further, the non-eutectic borides showed stronger crystallographic texture, lower in-grain misorientations, orientation gradients, and significantly lower residual stresses. The non-eutectic borides appeared to originate as primary dendrites during the initial solidification stages. In contrast, eutectic borides and ferrites formed subsequently in the interdendritic arms. Growth selection of the non-eutectic borides and back-stress relaxation at the dendrite boundaries appeared to define the differences in phase-specific microstructures of the ceramic-matrix composite.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"43 ","pages":"Article 102534"},"PeriodicalIF":2.9,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"These ones are small; those ones are far away: A comparison of macro and in-situ micro tensile testing techniques","authors":"S. Taylor ,&nbsp;S. Dhara ,&nbsp;R. Beaumont ,&nbsp;S. Krauss ,&nbsp;A. Zeybek ,&nbsp;G.D. West","doi":"10.1016/j.mtla.2025.102533","DOIUrl":"10.1016/j.mtla.2025.102533","url":null,"abstract":"<div><div>An aluminium AA7020 alloy was investigated in both the as received cold rolled condition and in the w-temper condition after heat treatments in both macro tensile and in-situ micro tensile tests to verify test parameters for in-situ testing to improve understanding of the validity of micro results to bulk properties. A variety of macro scale geometries conforming to ISO standards, and micro scale geometries were tested in the as received cold rolled condition to identify the optimal thickness of tensile samples to replicate bulk physical properties. Both macro and micro DIC (digital image correlation) techniques were utilised to confirm accurate strain paths in said geometries. W-temper specimens were then subjected to interrupted EBSD (electron back-scattered diffraction) scans during in-situ tensile tests to understand the microstructural evolution of the material during deformation and understand what impact the pauses in deformation have on physical properties. This study identified that for accurate physical properties to be derived from in-situ micro samples they need to be thinned to achieve a width to thickness ratio of around 5, and that interrupted tests significantly alter the UTS (ultimate tensile strength) and strain to failure so need to be combined with non-interrupted tests to derive accurate properties.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"43 ","pages":"Article 102533"},"PeriodicalIF":2.9,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144912754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of high gravity on the directional solidification of lead-tin (PbSn) eutectic alloy","authors":"Plínio Ivo Gama Tenório,&nbsp;Rafael Cardoso Toledo,&nbsp;Maurício Ribeiro Baldan,&nbsp;Irajá Newton Bandeira,&nbsp;Chen Ying An","doi":"10.1016/j.mtla.2025.102530","DOIUrl":"10.1016/j.mtla.2025.102530","url":null,"abstract":"<div><div>The eutectic PbSn alloy was directly solidified by vertical gradient freeze technique under high gravity conditions, with gravitational acceleration equal to 1 g, 9 g, and 10 g (where <em>g</em> = 9.81 m/s²). The density of the was determined using Archimedes' principle, and the atomic percentage of solute along the longitudinal direction was estimated using the mixture rule. The cooling data indicated an undercooling phenomenon for samples solidified at high accelerations. Microstructure characterization showed composition differences along the sample length of the samples, attributed to gravity-driven solute sedimentation during solidification. This sedimentation resulted in distinct microstructures: primary and dendritic phases as well as regular and anomalous eutectic structures.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"43 ","pages":"Article 102530"},"PeriodicalIF":2.9,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144891964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis of morphologically controllable BiVO4/Bi2O2CO3 heterojunction nanocomposites with visible light photocatalytic and electrocatalytic properties","authors":"Ruiyu XU ,&nbsp;Tianyu ZHANG ,&nbsp;Yefan Tang ,&nbsp;Dayu LI","doi":"10.1016/j.mtla.2025.102528","DOIUrl":"10.1016/j.mtla.2025.102528","url":null,"abstract":"<div><div>BiVO₄/Bi₂O₂CO₃ heterojunction nanocomposite was prepared using a solvothermal reaction method with urea as the auxiliary solution. The formation of Bi₂O₂CO₃ generated in the reaction process was controlled by the amount of urea. The particle morphology was gradually changed from a dense spindle structure of pure BiVO₄ to a sheet structure of BiVO₄/Bi₂O₂CO₃, and these sheet structures tend to become thicker as the urea content increases. The phase transformation can generate more active sites and effectively control the recombination of photogenerated electron-hole pairs, enhancing the photogenerated carrier separation. The degradation rate of methylene blue for the heterojunction nanocomposite is about 2 times that of BiVO₄. From the hydrogen evolution reaction data, it is also found from the data of hydrogen evolution that BiVO₄/Bi₂O₂CO₃ has high kinetic performance and faster electrocatalytic efficiency, and the hydrogen evolution performance is enhanced.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"43 ","pages":"Article 102528"},"PeriodicalIF":2.9,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical behavior and structural complexity of nature-inspired porous materials across scales","authors":"Seo Young Ahn,&nbsp;Ryan Nielsen,&nbsp;Pania Newell","doi":"10.1016/j.mtla.2025.102518","DOIUrl":"10.1016/j.mtla.2025.102518","url":null,"abstract":"<div><div>Porous materials are essential in applications ranging from energy storage to healthcare and play a crucial role in advancing technology and enhancing the quality of life. Understanding the impact of pore morphology across different length scales on mechanical properties is necessary for the efficient design of porous structures and also to ensure the structural integrity of the structures. This study investigates the impact of morphological complexities on the mechanical properties of nature-inspired architected porous materials through pillar compression tests at micro and macro scales. Complexity was determined through the surface fractal analysis of each sample, resulting in idealistic, semi-realistic, and realistic complexity definitions. Results show that semi-realistic and realistic structures exhibit similar stress–strain behavior and micromechanical values, while idealized structures demonstrate lower properties. Moreover, for the same porosity level, loading–unloading loops reveal similar degradation of Young’s modulus across each morphology. However, this impact is significantly influenced by the porosity level and becomes more pronounced at lower strain values for lower porosity. Furthermore, macroscale investigation confirms that semi-realistic and realistic structures exhibit identical behaviors. Additionally, our finite element models demonstrate the power of numerical methods in predicting the behavior of complex pore morphologies. These insights into the structure–property relationships can inform the design of more efficient materials and structures.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"43 ","pages":"Article 102518"},"PeriodicalIF":2.9,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144880297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ag-Cu amorphous alloy thin-films with unusually high electrical conductivity","authors":"Santanu Das ,&nbsp;Srivilliputhur G. Srinivasan ,&nbsp;Sundeep Mukherjee","doi":"10.1016/j.mtla.2025.102525","DOIUrl":"10.1016/j.mtla.2025.102525","url":null,"abstract":"<div><div>Copper is the state-of-the-art interconnect material in integrated circuits and other electronic applications. At the deeply scaled-down dimensions of a few nanometers, the resistivity of polycrystalline copper and other metals increases sharply due to enhanced electron scattering at grain boundaries and interfaces. Here, we report that fully amorphous thin-films of binary Ag-Cu alloy could potentially overcome the above limitations imposed by interfaces. The resistivity of 10 nm thick Ag-Cu amorphous film is ∼ 2.97 μOhm-cm, pure Ag film is ∼ 1.59 μOhm-cm, and pure Cu film is ∼ 20.5 μOhm-cm of similar thickness. The valence band structure of the amorphous film reveals that <em>d-band</em> interaction between Ag and Cu atoms broadens the electronic density of states resulting in high electrical conductivity. Our approach offers a new strategy for the potential use of amorphous metals as interconnects in advanced technology nodes and deeply-scaled electronics.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"43 ","pages":"Article 102525"},"PeriodicalIF":2.9,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144880296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}