Journal of the American Ceramic Society最新文献

{"title":"Phase relations in the Bi2O3–Mn2O3–M2O3 (MFe, Al, and Ga) pseudoternary systems","authors":"Srečo D. Škapin,&nbsp;Amalija Golobič,&nbsp;Matjaž Spreitzer,&nbsp;Danilo Suvorov","doi":"10.1111/jace.20323","DOIUrl":"https://doi.org/10.1111/jace.20323","url":null,"abstract":"<p>This study establishes the subsolidus phase relations in the Bi₂O₃–Mn₂O₃–M₂O₃ (M = Fe, Al, and Ga) systems at 770°C in an oxidizing air environment, with a specific focus on identifying of phase stability and extension of solid solubility of new solid solutions. The pseudoternary nature of these systems is influenced by the presence of both Mn³⁺ and Mn⁴⁺ oxidation states in mullite Bi₂Mn₄O₁₀-based phases and Mn⁴⁺ in sillenite Bi₁₂MnO₂₀-based phases. Our findings reveal that the addition of M₂O₃ (where M = Fe, Al, and Ga) in small amounts (up to 1.5 mol%) to Bi₂O₃ promotes the formation of the γ-Bi₂O₃ phase. However, with increased M₂O₃ addition (up to 7 mol%), isomorphous sillenite compounds Bi₂₅MO₃₉ are formed. These findings clearly show differences between the two phases, γ-Bi₂O₃ and sillenite Bi₂₅MO₃₉ which have been largely incorrectly defined in the past. In contrast, in the binary system Bi₂O₃–Mn₂O₃ the γ-Bi₂O₃ was not identified. The sillenite compounds Bi₁₂MnO₂₀ and Bi₂₅MO₃₉ exhibit solid solubility in all three systems M = Fe, Al, and Ga over the entire composition range. Additionally, the perovskite phase BiFeO₃ exhibits an extended solid solubility, incorporating up to 32 at% of Mn as a substitution for Fe however the perovskite-type BiGaO₃ and BiAlO₃ were not confirmed in the investigated systems. In the investigated systems, the mullite-type Bi₂Mn₄O₁₀ and Bi₂M₄O₉ (M = Fe, Al, and Ga) form solid solutions with various compositional extensions, which depends on the difference of ionic size of M atoms (Fe, Al, and Ga) in comparison of Mn size. Based on experimental results, the three phase diagrams of the Bi₂O₃–Mn₂O₃–M₂O₃ (M = Fe, Al, and Ga) systems were constructed.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jace.20323","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Apparent fracture toughness estimation of additively manufactured alumina from as-printed chevron-notched test specimens","authors":"Patrick L. Snarr,&nbsp;Kris V. Jones,&nbsp;Emily F. Ghezawi,&nbsp;Andrew A. Wereszczak,&nbsp;Corson L. Cramer","doi":"10.1111/jace.20327","DOIUrl":"https://doi.org/10.1111/jace.20327","url":null,"abstract":"<p>Ceramic vat photopolymerization (VPP) is a digital light processing method used to make additively manufactured green ceramic components that are then sintered. Despite the ever-advancing maturation of this method's green-state process, some of the material properties of sintered VPP-processed ceramics are still not well defined or understood. One example is Mode I fracture toughness, <i>K</i>_Ic. In this study, attention was devoted to <i>K</i>_Ic measurement using net-shape chevron-notched bend bars that were VPP-processed and the examination of whether valid <i>K</i>_Ic measurement could occur by testing them. Stable crack propagation was observed in &gt;60% of tested samples, indicated by a smooth nonlinear transition through the measured maximum force prior to final fracture. However, their results cannot yet be responsibly referred to as <i>K</i>_Ic because of continuing violations of other prerequisites needed for valid <i>K</i>_Ic testing.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143117032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The mechanical properties of irradiated concrete aggregates: Insights from molecular dynamics simulations","authors":"Takayoshi Fujimura,&nbsp;Yuji Hakozaki,&nbsp;Shunsuke Sakuragi,&nbsp;Yuu Nakajima,&nbsp;Kenta Murakami,&nbsp;Kiyoteru Suzuki,&nbsp;Ippei Maruyama,&nbsp;Takahiro Ohkubo","doi":"10.1111/jace.20318","DOIUrl":"https://doi.org/10.1111/jace.20318","url":null,"abstract":"<p>The concrete in nuclear power plant reactor buildings is exposed to neutron radiation, making it critical to evaluate and predict its deterioration under irradiation. The observed expansion of irradiated concrete is believed to be caused by the expansion of aggregate minerals, but the mechanisms behind this process are not well understood. This study uses molecular dynamics simulations to investigate the mechanical properties and mechanical fracture phenomena of a range of silicate minerals that are popular as concrete aggregates. Ten silicate minerals are targeted: <span></span><math>\u0000 <semantics>\u0000 <mi>α</mi>\u0000 <annotation>$alpha$</annotation>\u0000 </semantics></math>-quartz, orthoclase, microcline, albite, oligoclase, andesine, labradorite, augite, diopside, and forsterite. The mechanical properties (Young's modulus, maximum stress, and Poisson's ratio) of the minerals are determined through neutron irradiation and tensile simulations. The irradiation simulations reveal a decrease in mineral density, an expansion process involving amorphousization, and a change from anisotropic to isotropic mechanical properties. The isotropic Young's modulus and maximum stress significantly decrease with irradiation, and this effect is reproduced well in experimental results. The origin and process of mechanical fracturing are estimated by finding atoms with large displacements in tensile simulations, and the behavior of the stress–strain curve on the atomic scale is explained. In irradiated minerals, local stress relaxation occurs due to local atomic displacement, and large-scale mechanical fractures are suppressed. The factors involved in the mechanical fracturing and local stress relaxation of Na-feldspar are identified and discussed in terms of chemical bonding theory.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143116393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of local geometry and relative energy on grain boundary area changes during grain growth in SrTiO3","authors":"Vivekanand Muralikrishnan,&nbsp;Zipeng Xu,&nbsp;Gregory S. Rohrer,&nbsp;Amanda R. Krause","doi":"10.1111/jace.20319","DOIUrl":"https://doi.org/10.1111/jace.20319","url":null,"abstract":"<p>This study uses high-energy X-ray diffraction microscopy of SrTiO₃ to identify correlations between grain boundary (GB) area changes and the motion direction of neighboring GBs to investigate interfacial energy minimization mechanisms during grain growth. The local GB area changes were measured near triple lines (TLs) to isolate the effects of neighboring GBs. These area changes were then correlated to the migration direction and curvature of the neighboring GBs present at the TL, providing an alternative metric associated with lateral expansion for describing GB migration. Additionally, this study extracted GB dihedral angles, which reflect the relative GB energy, to test whether low energy GBs replace high energy GBs (i.e., GB replacement mechanism) and, thus, can be used to predict a GB's migration direction. The majority of GBs did not exhibit local area changes reflective of the GB replacement mechanism, and the dihedral angles were not reliable indicators of GB motion. However, the expansion and shrinkage of GBs moving away from their center of curvature was more often consistent with the grain boundary replacement mechanism. These results suggest that growth for certain GB configurations is governed by relative energy differences while others are governed by curvature.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jace.20319","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143116162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystallographic assessment and thermal expansion fine-tuning of quartz solid solutions in the ZnO–MgO–Al2O3–SiO2 system","authors":"Beatriz Paiva Da Fonseca,&nbsp;Gundula Helsch,&nbsp;Alessio Zandonà,&nbsp;Joachim Deubener","doi":"10.1111/jace.20314","DOIUrl":"https://doi.org/10.1111/jace.20314","url":null,"abstract":"<p>Glass powders with compositions within the ZnO–MgO–Al₂O₃–SiO₂ system (without the addition of nucleating agents) were synthesized by spray-drying and carefully crystallized to obtain stuffed quartz solid solutions (Qz-ss). The substitution of Zn by Mg causes an increase in the crystallization temperature and the composition of Qz-ss varies during their formation, highlighting a nonisochemical precipitation with respect to the parent glass. A change from a low-temperature modification of Qz-ss to a high-temperature modification was visible for Qz-ss containing 80 or 90 mol% SiO₂. The high-temperature modification of Mg- and (Zn,Mg)-Qz-ss displays negative thermal expansion for SiO₂ content equal to 90 mol%, but a positive one for 80 and 67 mol%. In contrast, the high-temperature modifications of Zn-Qz-ss show a negative thermal expansion for the three SiO₂ contents studied. The properties of (Zn,Mg)-Qz-ss containing 67 mol% SiO₂ cannot be predicted by a linear interpolation between Zn-Qz-ss and Mg-Qz-ss. A (Zn,Mg)-Qz-ss with zero thermal expansion was crystallized by modulating SiO₂ content and Mg/Zn ratio.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jace.20314","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143116034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tuning interfacial wettability in high-entropy cemented carbides for enhanced mechanical performance","authors":"Jiaojiao Hu,&nbsp;Qiankun Yang,&nbsp;Weisong Wu,&nbsp;Yong Zhang,&nbsp;Dingshun Yan,&nbsp;Zhiming Li","doi":"10.1111/jace.20317","DOIUrl":"https://doi.org/10.1111/jace.20317","url":null,"abstract":"<p>This study investigated three newly developed high-entropy cemented carbides (HECCs) with high-entropy carbides (HECs) as the hard phase and Co as the binder. Accordingly, the interfacial wettability between HECs and Co was tuned by the changes in relative concentrations of the different metal components (e.g., W, Ta, and Ti) and C. Results demonstrate that the wettability between HECs and Co is dominated by the dissolution of HECs in Co, which determines the sintering behavior and hence the structure and performance of the materials. More specifically, the (W₆Ta₄Nb₁₀Zr₁₀Ti₂₀)C₅₀-Co with lower W content has poorer interfacial wettability, leading to pores in the sintered HECC. The (W₁₀Ta₁₀Nb₁₀Zr₁₀Ti₁₀)C₅₀-Co shows good interfacial wettability and strong resistance against grain boundary infiltration, owing to the formation of several atomic-layer-thick Co films between HEC grain boundaries. Reducing the C content facilitates the dissolution of HECs in Co, which can improve the interfacial wettability, but promotes the formation of η-W₃Co₃C phase and embrittle the material. The (W₁₀Ta₁₀Nb₁₀Zr₁₀Ti₁₀)C₅₀-Co with decent interfacial wettability exhibits a good balance of hardness (HV30 ∼1485), compressive strength (3316 MPa), and fracture toughness (10.9 MPa·m^1/2). The work demonstrates a design strategy achieving optimized microstructure and mechanical performance in HECCs via tuning interfacial wettability.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143116033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling and mapping polymorphs in fluorite Y2TiO5 using 4D-STEM and unsupervised machine learning","authors":"Eitan Hershkovitz,&nbsp;Timothy Yoo,&nbsp;Xiaofei Pu,&nbsp;Kaustubh Bawane,&nbsp;Tadachika Nakayama,&nbsp;Hisayuki Suematsu,&nbsp;Lingfeng He,&nbsp;Honggyu Kim","doi":"10.1111/jace.20309","DOIUrl":"https://doi.org/10.1111/jace.20309","url":null,"abstract":"<p>Y₂TiO₅ belongs to the Ln₂TiO₅ (Ln = lanthanide or Y) family of ceramic materials and exhibits a range of desirable material properties such as radiation tolerance, frustrated magnetism, and large dielectric constant. However, understanding the complex crystal structure of Y₂TiO₅ remains elusive, given that Y₂TiO₅ can adopt multiple polymorphs such as cubic, orthorhombic, and hexagonal phases within the lattice. In this work, we report a detailed structural analysis of Y₂TiO₅ using four-dimensional scanning transmission electron microscopy coupled with unsupervised machine learning. The pyrochlore nanodomains, characterized by the ordered arrangement of yttrium cations on the A site of their A₂BO₅ structure, are present within the matrix of a predominantly fluorite-structured Y₂TiO₅ along with a third polymorph, the hexagonal phase. The pyrochlore phase is found to form 2 nm boundary regions around hexagonal phase stacking faults, highlighting the potential influence of the hexagonal phase on the occurrence and distribution of the pyrochlore phase. Lastly, we identify a unique pyrochlore phase with asymmetric arrangement of cation ordering along a single planar direction. Our findings provide invaluable insights into the possible mechanisms stabilizing pyrochlore nanodomains within the fluorite lattice of Y₂TiO₅.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143115705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rheology and structure of ceramic stereolithography slurries: Role of powder nature, dispersant, and orthogonal strain","authors":"Sylvain Fournier,&nbsp;Jérôme Chevalier,&nbsp;Helen Reveron,&nbsp;William Chèvremont,&nbsp;Guilhem P. Baeza","doi":"10.1111/jace.20304","DOIUrl":"https://doi.org/10.1111/jace.20304","url":null,"abstract":"<p>We investigate the rheological properties of ceramic slurries designed for laser stereolithography manufacturing in relation to their formulation, including the powder morphology, their volume fraction, and the concentration of dispersing agent. By combining dynamic strain sweep and Small-Angle X-ray Scattering (SAXS) experiments, we first illustrate that slurry viscosity follows an exponential trend with increasing particles content, with steeper increase observed for more aggregated particles. We then show that increasing the dispersant concentration up to an optimal value decreases slurry viscosity, as SAXS measurements reveal a reduction and homogenization in agglomerate size. Finally, we evidence that applying vertical oscillatory deformation during steady shear flow induces fluidization of the slurry. The shear viscosity exhibits a time–strain rate equivalence, enabling the generalization of this effect across a wide range of formulations. This methodology holds potential for industrial applications, where introducing vibration perpendicular to the scraping blade motion could improve the surface quality of the spread slurry prior to polymerization.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143115712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural origin of anisotropic mechanical/thermal behavior in La2SrAl2O7 and Nd2SrAl2O7 perovskites","authors":"Bin Liu,&nbsp;Hui Zhou,&nbsp;Yuchen Liu,&nbsp;Shaoxun Li,&nbsp;Kaili Chu,&nbsp;Zhixue Qu,&nbsp;Wenxian Li,&nbsp;Yiran Li","doi":"10.1111/jace.20307","DOIUrl":"https://doi.org/10.1111/jace.20307","url":null,"abstract":"<p>Rare earth strontium aluminates have attracted much attention due to their excellent properties and widely functional applications. In this work, the bonding characteristics, mechanical/thermal properties, and phonon behavior of La₂SrAl₂O₇ and Nd₂SrAl₂O₇ with layered structure are investigated using first-principles calculations. The weak chemical bonds within the rock-salt layer lead to the anisotropy of elastic moduli, tensile, and shear strength, benefiting their damage tolerance. It is also found that the low-frequency phonons present much lower scattering rates, making themselves vital contributors to heat conduction. Owing to the enhanced anharmonicity, Nd₂SrAl₂O₇ exhibits lower thermal conductivity than La₂SrAl₂O₇. Moreover, the lower thermal conductivities are observed along the <i>z</i> direction, which is attributed to the anisotropic chemical bonding. These results clarify the role of the weak bonds within layered structures in modulating their mechanical and thermal performance, which is expected to shield light on the development of perovskites with layered Ruddlesden–Popper structures.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143115706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic and thermodynamic behavior of supercooled Na–Ba metaphosphate liquids: Role of modifier cation ordering","authors":"Shih-Yi Chuang,&nbsp;Ping Yu,&nbsp;Sabyasachi Sen","doi":"10.1111/jace.20313","DOIUrl":"https://doi.org/10.1111/jace.20313","url":null,"abstract":"<p>The Q-speciation and the role of modifier dynamics on network relaxation in the supercooled mixed-alkali–alkaline-earth (MAAE) Na–Ba metaphosphate liquids are investigated using a combination of ³¹P nuclear magnetic resonance (NMR) spectroscopy, calorimetric, electrical conductivity, and rheological measurements. Progressive replacement of Na with Ba in these glasses is shown to result in an increasing disproportionation of Q² species via the reaction: 2Q² = Q¹ + Q³. Unlike mixed-alkali liquids, the Na–Ba metaphosphate liquids display a monotonic variation in isothermal electrical conductivity, glass transition temperature, calorimetric and kinetic fragility, and isothermal viscosity. It is hypothesized that this monotonic variation arises from the lack of elastic facilitation of network relaxation via coupled hopping of Na–Ba pairs as these modifier cations are prohibited from mixing randomly due to the differences between their size, mass, charge, and mobility. Isobaric heat capacity measurements provide supporting evidence in favor of a such a nonrandom mixing between the modifier cations in Na–Ba metaphosphate glasses and liquids.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 4","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143115186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}