Acta Materialia最新文献

{"title":"Interaction and competition between continuous and geometric dynamic recrystallization in high-strain-rate deformation of nickel-based superalloys","authors":"Andrea la Monaca ,&nbsp;Dragos Axinte ,&nbsp;Zhirong Liao ,&nbsp;Nigel Neate ,&nbsp;Mark Hardy","doi":"10.1016/j.actamat.2025.121377","DOIUrl":"10.1016/j.actamat.2025.121377","url":null,"abstract":"<div><div>High-strain-rate shear deformation of advanced alloys is the bases of a wide range of processing methods (e.g. cutting, forming, shot peening) for highly engineered components used in a wide range of industries (e.g. aerospace, nuclear, automotive). When such shear deformations occur, layers of very fine equiaxed grains have been widely reported which are commonly explained via a continuous dynamic recrystallization (CDRX) mechanism. However, employing a cutting operation to induce shear deformations at high strain rates (10⁴–10⁵ s^-1) in a Ni-based superalloy we found features that cannot be explained by this classical approach. Here we quickly stopped the shear deformation process so that the phenomena leading to grain refinement can be inferred by examining the deformation zones in a time successive manner. Our analysis using Transmission Kikuchi Diffraction (TKD) and Transmission Electron Microscopy (TEM), we prove that the grain refinement is much more complex than previously reported as this is the result of a bi-modal mechanism where Geometric Dynamic Recrystallization (GDRX) combines with CDRX leading to unique microstructural features. We further supported the proposed bi-modal grain refinement mechanism by showing differences in mechanical properties by performing micro-pillar compression tests within targeted deformation zones (i.e. dominated by CDRX and GDRX+CDRX). These findings highlight new mechanisms of dynamic recrystallization caused by high-strain-rate shear deformations which have pivotal importance on how to conduct key manufacturing processes so that the properties of resultant recrystallized layers can be controlled.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"297 ","pages":"Article 121377"},"PeriodicalIF":9.3,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144710827","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":"Designing ultrahigh-strength lightweight compositionally complex alloys through heterostructural composite engineering","authors":"Fengchao An ,&nbsp;Sihao Zou ,&nbsp;Jikui Liu ,&nbsp;Bing Zhang ,&nbsp;Xutao Huang ,&nbsp;Junhua Hou ,&nbsp;Bingnan Qian ,&nbsp;Xinyu Zhang ,&nbsp;Wenjun Lu","doi":"10.1016/j.actamat.2025.121375","DOIUrl":"10.1016/j.actamat.2025.121375","url":null,"abstract":"<div><div>Achieving a simultaneous enhancement in strength, ductility, and crack resistance remains a formidable challenge in structural alloys, particularly those employing dual-phase heterostructures. Although hetero-interfaces in such systems can promote heterogeneous deformation and strain hardening, they often act as stress concentrators, triggering interfacial strain localization and premature failure. Here, we report a novel heterostructural composite engineering strategy that concurrently minimizes local strain mismatch and enhances interfacial crack tolerance. By introducing Al and C into a lightweight CoNiV-based compositionally complex alloy (CCA), we engineer a unique face-centered cubic (FCC)/L2₁ composite architecture via a short-time annealing (900 °C, 1 min). This microstructure comprises L2₁-decorated recrystallized and non-recrystallized FCC regions, as well as FCC-embedded L2₁ islands, forming a gradient in both hardness and strain. Such a configuration significantly reduces the interphase hardness contrast (∼1.5 GPa), thereby activating pronounced heterogeneous deformation-induced (HDI) hardening while suppressing strain localization through cooperative plasticity between FCC and L2₁ phases. The resulting CCA exhibits an ultrahigh specific yield strength of 226 MPa·cm³/g and a uniform ductility of 14 %, outperforming previously reported precipitation-strengthened dual-phase CCAs. Deformation is governed by multistage strain hardening mechanisms, involving HDI hardening, dislocation slip, nanotwinning, and formation of 9R phases. Additionally, nanotwins and ductile FCC domains within L2₁ islands act as effective crack arresters, delaying crack initiation and propagation. This work establishes a new paradigm for designing CCAs with exceptional mechanical performance through hierarchical composite engineering.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"297 ","pages":"Article 121375"},"PeriodicalIF":9.3,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144710825","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":"Manipulating Piezoelectric and Electro-strain Properties of BiFeO3-BaTiO3-Based Ceramics through Chemical Doping-Controlled Domain-size Engineering","authors":"Jiamin Lin, Bing Liu, Mengxiang Liu, Shan Yang, Linming Zhou, Zijian Hong, Xiaoli Zhu, Yongjun Wu, Juan Li, Yuhui Huang","doi":"10.1016/j.actamat.2025.121379","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121379","url":null,"abstract":"Ferroelectric domains are crucial for the performance of piezoelectric ceramics, as the size and switching dynamics affect polarization response directly, manipulating both ferroelectric and piezoelectric properties. In this study, we achieved BiFeO₃-BaTiO₃ ceramics with domain sizes from macroscopic to nanoscale by incorporating a small amount of antiferroelectric phase. Contrary to the long-standing belief that smaller ferroelectric domains own lower polarization switching barriers and yield higher piezoelectricity, we found that in chemical doping-controlled domain size engineering, the smaller the domain size, the more difficult it is for polarization switching. Ceramics with the largest domain exhibited superior positive piezoelectric performance due to the sufficient polarization switching and reduced domain wall pinning, achieving a piezoelectric coefficient (<em>d</em>₃₃) of 460 pC/N at 350°C. Middle-sized domains achieved optimal electro-strain performance determined by the trade-off between the domain walls pinning and the increased local tetragonal or orthorhombic symmetries, with a strain (0.29%) and an excellent piezoelectric strain coefficient (<em>d</em>₃₃*) of 726.4 pm/V at 160°C. This work provides novel insights into how domain-size engineering affects domain switching and local distortion, offering guidance for performance optimization of piezoelectric ceramics.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"8 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144712405","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":"Discovery of a critical line in ferroelectric BaTiO3-BaZrO3-BaSnO3 Ternary system and designing of multi-layer multi-critical-composition ceramics with high permittivity over a broad temperature range utilizing the line","authors":"Xiaoqin Ke ,&nbsp;Songjie Ren ,&nbsp;Zhengkai Hong ,&nbsp;Jiajing Li ,&nbsp;Lichen Chen ,&nbsp;Sen Yang ,&nbsp;Xiaobing Ren","doi":"10.1016/j.actamat.2025.121381","DOIUrl":"10.1016/j.actamat.2025.121381","url":null,"abstract":"<div><div>Critical ferroelectric transitions are significant because they lead to remarkable material properties such as exceptionally high dielectric permittivity and enhanced piezoelectricity, a phenomenon that arises from the diminishing energy barrier between paraelectric and ferroelectric phases. However, ferroelectric materials with such critical transitions are exceedingly rare in nature. In this work we explore the phase diagram of the pseudoternary system (1-<em>x</em>) BaTiO3-<em>x</em> (1-<em>y</em>) BaZrO3-<em>xy</em> BaSnO₃, where we identify a continuous line of compositions that demonstrate critical ferroelectric transitions. These compositions all exhibit high dielectric permittivity (<em>ε</em>&gt;40,000), coupled with a substantial electrocaloric effect (an adiabatic temperature change Δ<em>T</em>_ad &gt;0.49 K at 20 kV/cm) at their corresponding Curie temperatures. To leverage the potential of these critical compositions, we fabricated multilayer ceramics consisting of various compositions along this critical line with sequential Curie temperatures, resulting in large dielectric permittivity values across a broad temperature range (a maximum of 23,800 over a temperature span of ∼50 K). This study not only unveils a general approach to discovering a range of ferroelectric materials with critical transitions but also presents exciting opportunities for the development of innovative electroactive devices.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"297 ","pages":"Article 121381"},"PeriodicalIF":9.3,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144712404","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":"High-entropy engineered dipole glass in tungsten bronzes for high capacitive energy storage","authors":"Hao Zhang ,&nbsp;Tengfei Hu ,&nbsp;He Qi ,&nbsp;Huifen Yu ,&nbsp;Lisha Li ,&nbsp;Jie Wu ,&nbsp;Liang Chen ,&nbsp;Jun Chen","doi":"10.1016/j.actamat.2025.121380","DOIUrl":"10.1016/j.actamat.2025.121380","url":null,"abstract":"<div><div>Tungsten bronze, the second largest ferroelectric family after perovskite, has been extensively studied in the field of dielectric energy storage. However, tungsten bronze ceramics, especially the filled type, face a severe challenge of reaching high energy density and high efficiency, making it difficult to match the energy storage performance of perovskites. In this work, we propose high-entropy strategy in filled type tungsten bronze ceramics to meticulously engineer dipole glass, manifesting as completely different polarization magnitudes and angles between adjacent dipoles. Combining the apparent enhancement of breakdown strength and the significant reduction of polarization hysteresis loss driven by highly disordered dipole glass, an impressive recoverable energy density of 8.9 J/cm³ with an ultrahigh efficiency of 91 % can be achieved in the high-entropy tetragonal filled tungsten bronze ceramics, endowing tungsten bronzes with considerable energy storage competitiveness compared to perovskites. This work provides an effective avenue to develop and expand new high-performance energy storage materials.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"297 ","pages":"Article 121380"},"PeriodicalIF":9.3,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144712175","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":"Enabling circularity of copper through nanoscale impurity control","authors":"Raymond Kwesi Nutor, Martina Ruffino, Adam Cohen Miles, Yug Joshi, Eric V. Woods, Mohammed Kamran Bhat, Syeda Ramin Jannat, Ubaid Manzoor, Isnaldi R. Souza Filho, Dierk Raabe, Baptiste Gault","doi":"10.1016/j.actamat.2025.121373","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121373","url":null,"abstract":"Copper (Cu) is essential to the electrification of society, yet primary Cu ores contain less than 1% metal, making mining insufficient to meet the demands of the clean energy transition. Recycling offers a viable alternative, reducing CO₂ emissions by up to 65%, but conductivity losses due to scrap-related impurities hinder its application in high-performance systems. In this work, we introduce a recycling strategy for Cu recovered from electric vehicle (EV) batteries, enabling direct and circular reuse. Through nanoscale analysis, we show that by gettering impurities into nanoparticles spaced approximately 40 nm apart, they become effectively “invisible” to conduction electrons. This self-cleaning mechanism maintains both electrical conductivity and mechanical integrity, turning detrimental impurities into functional alloying elements and facilitating the sustainable reuse of Cu.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"1 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144701646","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":"Novel Zn-doped Nasicon-based glass-ceramic with superior Li-conductivity and enhanced properties as a solid electrolyte","authors":"S. Taoussi, A. Ouaha, M. Naji, K. Hoummada, A. Lahmar, B. Manoun, A. El bouari, H. frielinghaus, Y. Zhang, L. Bih","doi":"10.1016/j.actamat.2025.121374","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121374","url":null,"abstract":"Among the diverse array of solid electrolyte options, glass-ceramics hold great promise for application in all-solid-state lithium batteries. In this respect, we have effectively developed novel glasses and glass-ceramics through an innovative approach that integrates a glass-ceramic strategy with the newly introduced zinc-doped Nasicon phase. This was achieved by applying melt-quenching techniques coupled with meticulous control over the crystallization process, guided by a thorough study of crystallization kinetics. The crystallization kinetics have unveiled a two-dimensional nucleation mechanism with an activation energy of 165 kJ.mol^-1. X-ray diffraction (XRD) analysis revealed the emergence of a novel Zn-doped Nasicon phase, identified as Li_1.6Zn_0.3Ti_1.7(PO₄)₃, within the 30Li₂O-20ZnO-20TiO₂-30P₂O₅ glass-ceramic, a validation corroborated through Rietveld refinement. Indeed, FT-IR, Raman, and NMR analyses confirmed the formation of Li_1+2xZn_xTi_2-x(PO₄)₃ Nasicon phase within the glass-ceramics structures. Moreover, SEM images, complemented by TEM observations and density assessments, provide evidence for the creation of a dense, pore-free glass-ceramic with a striped microstructure. The 30Li₂O-20ZnO-20TiO₂-30P₂O₅ glass-ceramic demonstrates outstanding chemical durability and robust mechanical properties. Notably, it exhibits high total ionic conductivity, reaching 7.14.10^-4 Ω^-1.cm^-1 at room temperature, while displaying low electronic conductivity of 8.10^-9 Ω^-1.cm^-1, aligning with findings from UV-visible spectroscopy. Additionally, the lithium transference number is confirmed to be 0.99, positioning the developed glass-ceramic as a highly competitive solid electrolyte in the field of energy storage. DFT calculations were conducted on the crystallized Li_1.6Zn_0.3Ti_1.7(PO₄)₃ NASICON phase to gain detailed insights into its thermodynamic stability and electronic properties.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"21 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144710826","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":"Microstructural control across multiple length scales in additively manufactured Ti-6Al-4V via cyclic heat treatments","authors":"Sahil Dhiman ,&nbsp;Milan Brandt ,&nbsp;Daniel Fabijanic ,&nbsp;Viswanath Chinthapenta ,&nbsp;Wei Xu","doi":"10.1016/j.actamat.2025.121372","DOIUrl":"10.1016/j.actamat.2025.121372","url":null,"abstract":"<div><div>Ti-6Al-4V is a premier titanium alloy widely used across various industrial sectors, thanks to its versatile properties arising from diverse microstructures tailorable via thermomechanical processing (TMP). In contrast, Ti-6Al-4V made by laser powder-bed fusion (LPBF) additive manufacturing (AM) lacks the same microstructural diversity and precise in-process microstructural control, primarily due to rapid thermal cycling inherent to LPBF. In the as-built state, the microstructure predominantly comprises acicular α′ martensites within columnar prior-β grains, which often fails to achieve mechanical properties comparable to those obtained through TMP. This necessitates the use of post-heat treatments as a critical step to ensure superior and reliable mechanical performance. The present study explores cyclic heat treatment (CHT) as an effective strategy for AM-specific microstructural control across multiple length scales, including prior-β grains, primary α, and secondary α. By varying peak temperature, number of cycles, and cooling rate, the initial microstructure dominated by α′ martensite in columnar prior-β grains rapidly evolves into diverse microstructures comparable to those achieved via TMP. These include lamellar α+β in equiaxed prior-β grains, globular α in near-equiaxed prior-β grains, and bimodal microstructure comprising a mixture of globular α and lamellar α+β/acicular α′. The accelerated microstructural evolution driven by the repetitive α↔β phase transformations induced by CHT facilitates processes like epitaxial recrystallisation and α globularisation. The developed CHT protocol provides a framework for microstructural engineering, enabling mechanical property optimisation and supporting broader industrial adoption of LPBF Ti-6Al-4V.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"297 ","pages":"Article 121372"},"PeriodicalIF":8.3,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144693608","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":"Improving Creep Properties of IN718/316LN Transient Liquid Phase Bonding Joints by Controlling Evolution of Precipitate Phases","authors":"Miao Yang, Teng Zhang, Ran Ding, Tianyu Du, Qianying Guo, Feng Ma, Guowei Qi, Zhengang Guo, Qianying Guo, Chenxi Liu, Yongchang Liu","doi":"10.1016/j.actamat.2025.121356","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121356","url":null,"abstract":"A long-term post-bonded homogenization treatment (PBHT) was designed to improve the creep properties of IN718/BNi-2/316LN transient liquid phase (TLP) bonding joints. Compared to conventional PBHT, creep life improved more than tenfold at 650°C and 150 MPa. Long-term PBHT inhibits cavities nucleation and growth by controlling precipitate evolution, effectively delaying creep rupture and reducing strain rate, as revealed by microstructural analysis and density functional theory (DFT). The segregation of Nb, Mo, and Si at the grain boundary, combined with the reduced nucleation energy barrier of Nb₃Si, facilitates its nucleation. Nb₃Si phase can modify the creep cavities shape factor, increase the cavities nucleation energy barrier, and reduce the cavities nucleation rate, thus delaying cavities formation. Additionally, high vacancy formation energy and interfacial adhesion work at the Nb₃Si/Ni interface further hinder the cavities nucleation. A kinetics model for creep cavities evolution is proposed based on the coordinative evolution between precipitates and cavities. This model can quantitatively describe the growth and coalescence of creep cavities and predict the creep rupture time accurately based on the dynamic evolution of intergranular precipitate phases. These findings provide insights into improving the creep properties of joints and heterogeneous materials, where creep cavities nucleate around precipitates.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"699 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144693609","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":"Modeling the evolution of slip localization: Realization of link to material strength","authors":"Behnam Ahmadikia, Chris Bean, Jean-Charles Stinville, Tresa M. Pollock, Irene J. Beyerlein","doi":"10.1016/j.actamat.2025.121314","DOIUrl":"https://doi.org/10.1016/j.actamat.2025.121314","url":null,"abstract":"Slip localization formation is the chief mechanism underlying the deformation of nearly all metals, from pure elements to high-performance superalloys. The intensity of individual slip localizations is often related to the ultimate strain level for failure but not to the strength of the metal. Here we show that across 15 distinct metals, the intensity of slip in individual slip localizations and slip localization spacings are strongly related to material yield strength. Using a three-dimensional crystal plasticity-based micromechanical model that explicitly simulates the growth of discrete slip localizations, we reveal that the stronger the metal, the faster and earlier slip localizations intensify. The relationship is attributed to the formation of a zone that surrounds the slip localization where the driving force for slip is absent. We find that the zone size is controlled by the strength of the neighboring crystal. Consequently, as strength increases, slip becomes increasingly preferred within the slip localization itself and formation of other slip localizations becomes more likely further away.","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"123 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144693674","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}