Materialia最新文献_第2页

Aluminium-induced modulation of reaction kinetics and polytype formation in silicon carbide synthesized through high-energy ball milling

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-02-01 DOI: 10.1016/j.mtla.2025.102357

Sarah Morais Bezerra , Gábor Bortel , Nikoletta Jegenyes , Adam Gali , David Beke

Silicon carbide (SiC) is a versatile material employed in a broad range of applications, including abrasives, power electronics, and emerging quantum technologies. It is widely recognized as a high-performance technical ceramic, owing to its good thermal conductivity, high hardness, and chemical stability. Cost-effective strategies for synthesizing SiC with application-specific properties are thus highly desired, stimulating the development of numerous approaches to produce high-quality products. Direct synthesis of SiC from elemental silicon and carbon offers precise control over crystal size and phase purity at temperatures lower than those required for the reaction between SiO₂ and carbon. Nonetheless, further reductions in reaction temperature are desired to enhance both cost- and energy efficiency. This study explores the combined effects of high-energy ball milling, combustion synthesis, and aluminium addition on the formation of SiC. Both the precursors and the resultant products were comprehensively characterized to elucidate the influence of these processing methods. The results indicate that aluminium, in the studied 0–20 mol% concentration range, reduces the reaction time and increases the prevalence of hexagonal inclusions. In contrast, wet high-energy ball milling demonstrates only a marginal mechanical activation effect, which contradicts the previous results of dry milling. Furthermore, the oversaturation threshold (5 mol% Al in SiC) critically impacts both the synthesis process and the resulting material properties, thereby demonstrating the importance of composition control during synthesis.

{"title":"Aluminium-induced modulation of reaction kinetics and polytype formation in silicon carbide synthesized through high-energy ball milling","authors":"Sarah Morais Bezerra , Gábor Bortel , Nikoletta Jegenyes , Adam Gali , David Beke","doi":"10.1016/j.mtla.2025.102357","DOIUrl":"10.1016/j.mtla.2025.102357","url":null,"abstract":"<div><div>Silicon carbide (SiC) is a versatile material employed in a broad range of applications, including abrasives, power electronics, and emerging quantum technologies. It is widely recognized as a high-performance technical ceramic, owing to its good thermal conductivity, high hardness, and chemical stability. Cost-effective strategies for synthesizing SiC with application-specific properties are thus highly desired, stimulating the development of numerous approaches to produce high-quality products. Direct synthesis of SiC from elemental silicon and carbon offers precise control over crystal size and phase purity at temperatures lower than those required for the reaction between SiO₂ and carbon. Nonetheless, further reductions in reaction temperature are desired to enhance both cost- and energy efficiency. This study explores the combined effects of high-energy ball milling, combustion synthesis, and aluminium addition on the formation of SiC. Both the precursors and the resultant products were comprehensively characterized to elucidate the influence of these processing methods. The results indicate that aluminium, in the studied 0–20 mol% concentration range, reduces the reaction time and increases the prevalence of hexagonal inclusions. In contrast, wet high-energy ball milling demonstrates only a marginal mechanical activation effect, which contradicts the previous results of dry milling. Furthermore, the oversaturation threshold (5 mol% Al in SiC) critically impacts both the synthesis process and the resulting material properties, thereby demonstrating the importance of composition control during synthesis.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"39 ","pages":"Article 102357"},"PeriodicalIF":3.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A TEM study of microstructure inhomogeneity in a superalloy powder: Implications for microstructure development

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-01-30 DOI: 10.1016/j.mtla.2025.102347

Hiroto S. Kitaguchi , Shiuli Banerjee , Himanshu Vashishtha , Wolfgang Theis , Paul Bowen , David M. Collins

For nickel-base superalloys fabricated from gas-atomised powders, the final microstructure must be related to the characteristics of the powder itself. This work provides detailed characterisation, primarily using transmission electron microscopy, to link microstructure, composition and crystallography of the nickel-base superalloy, RR1000. In the virgin state, the powder has significant chemical inhomogeneity between and within powder particles, including evidence of

γ^{'}

structural ordering. From solute enrichment remnant from solidification, these regions contain multiple phases including MC, M₂₃C

_{6}

and sigma (

σ

). Where the local composition is close to the stoichiometric chemistry of the respective phase, they evidently formed without the need for long range diffusional processes that are typically required for their formation. When the powder is heated, these phases, including

γ^{'}

, are retained. This study highlights how non-equilibrium characteristics of a gas atomised powder must infleuence microstructural development and, consequently, the selection of subsequent processing steps.

{"title":"A TEM study of microstructure inhomogeneity in a superalloy powder: Implications for microstructure development","authors":"Hiroto S. Kitaguchi , Shiuli Banerjee , Himanshu Vashishtha , Wolfgang Theis , Paul Bowen , David M. Collins","doi":"10.1016/j.mtla.2025.102347","DOIUrl":"10.1016/j.mtla.2025.102347","url":null,"abstract":"<div><div>For nickel-base superalloys fabricated from gas-atomised powders, the final microstructure must be related to the characteristics of the powder itself. This work provides detailed characterisation, primarily using transmission electron microscopy, to link microstructure, composition and crystallography of the nickel-base superalloy, RR1000. In the virgin state, the powder has significant chemical inhomogeneity between and within powder particles, including evidence of <span><math><msup><mrow><mi>γ</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> structural ordering. From solute enrichment remnant from solidification, these regions contain multiple phases including MC, M<sub>23</sub>C<span><math><msub><mrow></mrow><mrow><mn>6</mn></mrow></msub></math></span> and sigma (<span><math><mi>σ</mi></math></span>). Where the local composition is close to the stoichiometric chemistry of the respective phase, they evidently formed without the need for long range diffusional processes that are typically required for their formation. When the powder is heated, these phases, including <span><math><msup><mrow><mi>γ</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span>, are retained. This study highlights how non-equilibrium characteristics of a gas atomised powder must infleuence microstructural development and, consequently, the selection of subsequent processing steps.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"39 ","pages":"Article 102347"},"PeriodicalIF":3.0,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172318","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}

引用次数: 0

The effect of silicon and boron doping on the microstructure of arc melted boron carbide

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-01-28 DOI: 10.1016/j.mtla.2025.102353

Zeynep Ayguzer Yasar , Kent Christian , Richard A. Haber

In this study, B₄C, boron-doped boron carbide, and Si/B co-doped boron carbide (1.5 at.% and 2.5 at.% made with Si and SiB₆) were arc melted. Melted ingots were characterized by X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and Vickers hardness. According to the results, doping of boron carbide with both silicon and boron was successfully achieved by arc melting. When Si/B doped boron carbide samples were examined, the same boron carbide, silicon boron, and silicon phases were found regardless of the silicon source. It was observed that dissolving silicon in boron carbide was more difficult than dissolving boron in boron carbide, and therefore, diffusion of silicon is believed to be rather short distance. It was determined that Si/B co-doped samples had higher hardness values than undoped B₄C and boron doped B_6.5C. Moreover, since very high temperatures are reached in the arc melting method, it has been determined that the oxides present in the starting powders evaporate during the melting process and therefore the oxygen content of the final melt ingots is very low.

{"title":"The effect of silicon and boron doping on the microstructure of arc melted boron carbide","authors":"Zeynep Ayguzer Yasar , Kent Christian , Richard A. Haber","doi":"10.1016/j.mtla.2025.102353","DOIUrl":"10.1016/j.mtla.2025.102353","url":null,"abstract":"<div><div>In this study, B<sub>4</sub>C, boron-doped boron carbide, and Si/B co-doped boron carbide (1.5 at.% and 2.5 at.% made with Si and SiB<sub>6</sub>) were arc melted. Melted ingots were characterized by X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and Vickers hardness. According to the results, doping of boron carbide with both silicon and boron was successfully achieved by arc melting. When Si/B doped boron carbide samples were examined, the same boron carbide, silicon boron, and silicon phases were found regardless of the silicon source. It was observed that dissolving silicon in boron carbide was more difficult than dissolving boron in boron carbide, and therefore, diffusion of silicon is believed to be rather short distance. It was determined that Si/B co-doped samples had higher hardness values than undoped B<sub>4</sub>C and boron doped B<sub>6.5</sub>C. Moreover, since very high temperatures are reached in the arc melting method, it has been determined that the oxides present in the starting powders evaporate during the melting process and therefore the oxygen content of the final melt ingots is very low.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"39 ","pages":"Article 102353"},"PeriodicalIF":3.0,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Heterostructural decomposition in V1-xWxB2-Δ films induced by B deficiency

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-01-28 DOI: 10.1016/j.mtla.2025.102351

Katarína Viskupová , Tomáš Fiantok , Branislav Grančič , Peter Švec Jr , Tomáš Roch , Martin Truchlý , Viktor Šroba , Leonid Satrapinskyy , Peter Kúš , Marián Mikula

Transition metal borides (TMB_y) represent a structurally rich group of materials with attractive physical properties, including high hardness and high melting points, making them promising candidates for applications in extreme conditions. Considerable attention has been paid to overstoichiometric TMB_2+Δ films with hexagonal α-P6/mmm structure exhibiting super-hardness attributed to high cohesive strength between excess-boron tissue phase and crystalline nanocolumns. However, positive effects of reducing the boron content in terms of toughness and oxidation resistance have been reported. Lowering the boron to metal ratio can have various effects on structure and stability, depending on the specific diboride system and its affinity to boron vacancies. In this work, we study the influence of boron understoichiometry on structure and thermal stability of vanadium tungsten diboride films. We present results of high-resolution scanning transmission electron microscopy showing that boron deficiency leads to a high density of planar defects, including anti-phase boundaries (APB-2i), the accumulation of which enables the formation of WB-Cmcm areas coherently included in the hexagonal VB₂-P6/mmm structure. The observation is supported by density functional theory calculations showing that since the presence of vacancies is favored by the α-WB₂ and not convenient for the α-VB₂ system, there is an increased probability of decomposition into stoichiometric VB₂ and boron deficient WB_z<2 products. Additionally, we report on other types of planar defects, such as twinning, and discuss their role in local formation of other boride phases within the Cmcm structure.

{"title":"Heterostructural decomposition in V1-xWxB2-Δ films induced by B deficiency","authors":"Katarína Viskupová , Tomáš Fiantok , Branislav Grančič , Peter Švec Jr , Tomáš Roch , Martin Truchlý , Viktor Šroba , Leonid Satrapinskyy , Peter Kúš , Marián Mikula","doi":"10.1016/j.mtla.2025.102351","DOIUrl":"10.1016/j.mtla.2025.102351","url":null,"abstract":"<div><div>Transition metal borides (TMB<sub>y</sub>) represent a structurally rich group of materials with attractive physical properties, including high hardness and high melting points, making them promising candidates for applications in extreme conditions. Considerable attention has been paid to overstoichiometric TMB<sub>2+Δ</sub> films with hexagonal α-<em>P6/mmm</em> structure exhibiting super-hardness attributed to high cohesive strength between excess-boron tissue phase and crystalline nanocolumns. However, positive effects of reducing the boron content in terms of toughness and oxidation resistance have been reported. Lowering the boron to metal ratio can have various effects on structure and stability, depending on the specific diboride system and its affinity to boron vacancies. In this work, we study the influence of boron understoichiometry on structure and thermal stability of vanadium tungsten diboride films. We present results of high-resolution scanning transmission electron microscopy showing that boron deficiency leads to a high density of planar defects, including anti-phase boundaries (APB-2i), the accumulation of which enables the formation of WB-<em>Cmcm</em> areas coherently included in the hexagonal VB<sub>2</sub>-<em>P6/mmm</em> structure. The observation is supported by density functional theory calculations showing that since the presence of vacancies is favored by the α-WB<sub>2</sub> and not convenient for the α-VB<sub>2</sub> system, there is an increased probability of decomposition into stoichiometric VB<sub>2</sub> and boron deficient WB<sub>z<2</sub> products. Additionally, we report on other types of planar defects, such as twinning, and discuss their role in local formation of other boride phases within the <em>Cmcm</em> structure.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"39 ","pages":"Article 102351"},"PeriodicalIF":3.0,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Deciphering the role of microstructural length scale on corrosion behaviour of carbide free nano-structured bainite using immersion in chloride solution

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-01-28 DOI: 10.1016/j.mtla.2025.102354

Bhawesh Chhajed , Kritika Singh , Aparna Singh

Nano-structured bainite (NSB) shows superior strength, ductility, and toughness owing to the nanometric microstructure. This study aims to provide a comprehensive understanding about the effect of microstructural refinement on aqueous corrosion behaviour of NSB while keeping the bainitic volume fraction constant. Two different austenitization temperatures (900 °C and 1000 °C) followed by austempering at 250 °C resulted in different prior austenite grain size (PAGS) which led to correspondingly different bainitic lath thickness. The specimens were subjected to immersion test in 3.5 wt% NaCl solution for 10, 20, 30, 40 and 50 days. Specimen having finer bainitic lath thickness displayed lower corrosion rate and weight loss due to immersion. Cross sectional imaging using scanning electron microscope (SEM) revealed shallower penetration of electrolyte in case of finer bainitic lath specimen resulting in formation of a compact, uniform and adhered corrosion layer in comparison to a loose and non-uniform layer observed for coarser bainitic lath specimen. Raman spectroscopy and x-ray photoelectron spectroscopy (XPS) revealed oxyhydroxides to be present in larger proportions in specimens subjected to immersion for 10 days while specimens subjected to immersion for 30 days had higher proportions of oxides as compared to oxyhydroxides. Further immersion up to 50 days resulted in higher proportions of oxyhydroxides in case of both heat treated specimens. Electrochemical tests such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) conducted on specimens immersed for 30 days showed that finer bainitic lath specimen displays higher corrosion resistance despite having thinner corrosion layer owing to its high compactness.

{"title":"Deciphering the role of microstructural length scale on corrosion behaviour of carbide free nano-structured bainite using immersion in chloride solution","authors":"Bhawesh Chhajed , Kritika Singh , Aparna Singh","doi":"10.1016/j.mtla.2025.102354","DOIUrl":"10.1016/j.mtla.2025.102354","url":null,"abstract":"<div><div>Nano-structured bainite (NSB) shows superior strength, ductility, and toughness owing to the nanometric microstructure. This study aims to provide a comprehensive understanding about the effect of microstructural refinement on aqueous corrosion behaviour of NSB while keeping the bainitic volume fraction constant. Two different austenitization temperatures (900 °C and 1000 °C) followed by austempering at 250 °C resulted in different prior austenite grain size (PAGS) which led to correspondingly different bainitic lath thickness. The specimens were subjected to immersion test in 3.5 wt% NaCl solution for 10, 20, 30, 40 and 50 days. Specimen having finer bainitic lath thickness displayed lower corrosion rate and weight loss due to immersion. Cross sectional imaging using scanning electron microscope (SEM) revealed shallower penetration of electrolyte in case of finer bainitic lath specimen resulting in formation of a compact, uniform and adhered corrosion layer in comparison to a loose and non-uniform layer observed for coarser bainitic lath specimen. Raman spectroscopy and x-ray photoelectron spectroscopy (XPS) revealed oxyhydroxides to be present in larger proportions in specimens subjected to immersion for 10 days while specimens subjected to immersion for 30 days had higher proportions of oxides as compared to oxyhydroxides. Further immersion up to 50 days resulted in higher proportions of oxyhydroxides in case of both heat treated specimens. Electrochemical tests such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) conducted on specimens immersed for 30 days showed that finer bainitic lath specimen displays higher corrosion resistance despite having thinner corrosion layer owing to its high compactness.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"39 ","pages":"Article 102354"},"PeriodicalIF":3.0,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313223","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}

引用次数: 0

Thermal analysis and Magnetic characterization of M-type SrFe12O19 nanodisks

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-01-28 DOI: 10.1016/j.mtla.2025.102352

R.L. Palomino-Resendiz , A. Castañeda-Ovando , A. Conde-Gallardo , S.I. Palomino- Resendiz , Y. Jaguey-Hernández , C. Tapia-Ignacio

In the present work, the thermodynamic analysis and magnetic properties as a function of temperature were investigated using calorimetric and VSM measurements of SrFe₁₂O₁₉ nanodisks, which were obtained by a sonochemical-assisted method. The XRD analysis confirms the successful synthesis of single-phase SrFe₁₂O₁₉ powder (98 wt.%) at 2.4 W/cm³, with a disk-shaped morphology revealed by SEM analysis. The TGA/DSC measurements show five stages of mass loss in the range of 273–1073 K, which are identified as an oxidation process. The activation energy (

E_{a}

) was determined using mass loss identifications from the thermogram and the Coats-Redfern model. This model provides overall kinetic data, such as the Gibbs free energy (

Δ

G), enthalpy (

Δ

H), and entropy (

Δ

S). In all cases, values of the

Δ

S were negative, demonstrating that the composite has a more organized structure compared to the starting material. The SrFe₁₂O₁₉ single-phase material showed superparamagnetic behavior with a coercivity field of 0.56 kOe at 100 K and a saturation magnetization of 71.05 emu/g, which was determined using the Law of Approach to Saturation method.

{"title":"Thermal analysis and Magnetic characterization of M-type SrFe12O19 nanodisks","authors":"R.L. Palomino-Resendiz , A. Castañeda-Ovando , A. Conde-Gallardo , S.I. Palomino- Resendiz , Y. Jaguey-Hernández , C. Tapia-Ignacio","doi":"10.1016/j.mtla.2025.102352","DOIUrl":"10.1016/j.mtla.2025.102352","url":null,"abstract":"<div><div>In the present work, the thermodynamic analysis and magnetic properties as a function of temperature were investigated using calorimetric and VSM measurements of SrFe<sub>12</sub>O<sub>19</sub> nanodisks, which were obtained by a sonochemical-assisted method. The XRD analysis confirms the successful synthesis of single-phase SrFe<sub>12</sub>O<sub>19</sub> powder (98 wt.%) at 2.4 W/cm<sup>3</sup>, with a disk-shaped morphology revealed by SEM analysis. The TGA/DSC measurements show five stages of mass loss in the range of 273–1073 K, which are identified as an oxidation process. The activation energy (<span><math><msub><mi>E</mi><mi>a</mi></msub></math></span>) was determined using mass loss identifications from the thermogram and the Coats-Redfern model. This model provides overall kinetic data, such as the Gibbs free energy (<span><math><mstyle><mi>Δ</mi></mstyle></math></span><em>G</em>), enthalpy (<span><math><mstyle><mi>Δ</mi></mstyle></math></span><em>H</em>), and entropy (<span><math><mstyle><mi>Δ</mi></mstyle></math></span><em>S</em>). In all cases, values of the <span><math><mstyle><mi>Δ</mi></mstyle></math></span><em>S</em> were negative, demonstrating that the composite has a more organized structure compared to the starting material. The SrFe<sub>12</sub>O<sub>19</sub> single-phase material showed superparamagnetic behavior with a coercivity field of 0.56 kOe at 100 K and a saturation magnetization of 71.05 emu/g, which was determined using the Law of Approach to Saturation method.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"39 ","pages":"Article 102352"},"PeriodicalIF":3.0,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172319","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}

引用次数: 0

Exploring solute segregation in sputtered W-10 at. % M (M=Ti, Ag, and Ta): Experimental insights and atomistic modeling

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-01-23 DOI: 10.1016/j.mtla.2025.102346

A.T. AlMotasem , N. Daghbouj , T. Huminiuc , J. Vesely , M. Karlik , M. Callisti , X. Zhang , T. Polcar

In the literature, many studies have reported Ti, Ag, and Ta significantly improve the thermal stability of nanocrystalline NC-W for high-temperature applications. However, their segregation behavior and impact on the mechanical properties of NC-W remain poorly understood. This study investigates the segregation behavior and its effects on the mechanical properties of W-M binary alloys (where M represents Ti, Ag, or Ta). Advanced transmission electron microscopy techniques and atomistic modeling are utilized for a comprehensive analysis. After high-temperature annealing, distinct behaviors are observed for each alloying element. Ti and Ag exhibit heterogeneous segregation in NC-W, resulting in solute-depleted/enriched grain boundaries (GBs). Conversely, Ta atoms form a solid solution without forming clusters. Hybrid Monte Carlo (MC)/molecular dynamics (MD) simulations support and elucidate these findings. Moreover, MD tensile testing reveals that the addition of Ti and Ag solutes results in softening, whereas the addition of Ta substantially enhances the strength of NC-W. The coalescence of small precipitates at the GBs leads to the nucleation of intragranular fractures, promoting GB plasticity and consequently softening the material. Conversely, the homogeneous distribution of Ta within the W matrix significantly suppresses the formation and extension of shear bands, thereby improving the strength of the NC-W.

{"title":"Exploring solute segregation in sputtered W-10 at. % M (M=Ti, Ag, and Ta): Experimental insights and atomistic modeling","authors":"A.T. AlMotasem , N. Daghbouj , T. Huminiuc , J. Vesely , M. Karlik , M. Callisti , X. Zhang , T. Polcar","doi":"10.1016/j.mtla.2025.102346","DOIUrl":"10.1016/j.mtla.2025.102346","url":null,"abstract":"<div><div>In the literature, many studies have reported Ti, Ag, and Ta significantly improve the thermal stability of nanocrystalline NC-W for high-temperature applications. However, their segregation behavior and impact on the mechanical properties of NC-W remain poorly understood. This study investigates the segregation behavior and its effects on the mechanical properties of W-M binary alloys (where M represents Ti, Ag, or Ta). Advanced transmission electron microscopy techniques and atomistic modeling are utilized for a comprehensive analysis. After high-temperature annealing, distinct behaviors are observed for each alloying element. Ti and Ag exhibit heterogeneous segregation in NC-W, resulting in solute-depleted/enriched grain boundaries (GBs). Conversely, Ta atoms form a solid solution without forming clusters. Hybrid Monte Carlo (MC)/molecular dynamics (MD) simulations support and elucidate these findings. Moreover, MD tensile testing reveals that the addition of Ti and Ag solutes results in softening, whereas the addition of Ta substantially enhances the strength of NC-W. The coalescence of small precipitates at the GBs leads to the nucleation of intragranular fractures, promoting GB plasticity and consequently softening the material. Conversely, the homogeneous distribution of Ta within the W matrix significantly suppresses the formation and extension of shear bands, thereby improving the strength of the NC-W.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"39 ","pages":"Article 102346"},"PeriodicalIF":3.0,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172289","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}

引用次数: 0

Mechanical properties and deformation mechanisms of phase-separated soda-lime-silica glass

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-01-23 DOI: 10.1016/j.mtla.2025.102349

Kevin Przepiora , Edgar Dutra Zanotto , N․M․Anoop Krishnan , Céline Ragoen , Stéphane Godet

The possibility that liquid phase separation enhances mechanical properties of glasses has recently garnered interest, yet questions persist regarding the mechanisms underlying these effects and their correlation with two-phase glass microstructures. To address these questions, the present study investigates some mechanical properties and the deformation response of a phase-separated soda-lime-silica glass with varying microstructures ranging from nanosized, interconnected to larger, dilute droplet structures. By maintaining a constant chemical composition, the direct influence of the microstructure morphology on certain mechanical properties is probed. Electron microscope images of crack tips reveal that the secondary phase can deflect and bridge propagating cracks in both interconnected and droplet microstructures, which is further confirmed by peridynamic simulations. Raman spectra show characteristic peak shifts of both amorphous silica and soda-lime glass during deformation, indicating a combined contribution of matrix and secondary phase. Notably, the interconnected structures exhibit smaller deformation zones, and cracks generated by low force indentations are significantly shorter compared to the droplet structures. These observed nanostructural effects lead to a 20 % increase in indentation fracture toughness and up to 40 % increase in flexural strength in interconnected structures. The increase in strength and toughness appears to be mainly related to the ability of certain morphologies to absorb stresses through densification of the secondary phase and to decrease the opening force of propagating cracks through crack deflection on interfaces.

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引用次数: 0

Hierarchal heterogeneity of microstructure via aging of Ti-6Al-4V alloy with α+α′ duplex initial microstructure and its effect on strengthening

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-01-23 DOI: 10.1016/j.mtla.2025.102348

Hiroaki Matsumoto , Takanori Kiguchi , Irvin Séchepée , Ryota Yoshioka

In this study, with the aim of further improving the strength and ductility balance of industrial Ti alloys, we investigated the phase decomposition behaviors of a Ti-6Al-4 V alloy with a (α+α′martensite) duplex microstructure during low-temperature aging (at 500 °C). In addition, we examined its effect on strength and ductility. The (α+α′) duplex microstructure (for the as-solution treated and quenched specimens) demonstrates a strength-ductility balance that is at par or better than that of the equilibrium (α+β) bimodal structure (for 700 °C aged specimen). The strength of the (α+α') duplex microstructure that was aged at 500 °C for 1 h was significantly increased while retaining good ductility. Here, although no apparent structural changes in both nano- and micro scale level were observed in the primary α grains, three unique phase decomposition/structural evolutions in nano scale level that formed new domains distinguished into the Area 1, 2, 3 were observed in the fine acicular α' martensite region as follows. Under aging at 500 °C, fine acicular α′ martensite evolves into ultrafine globular α′ grains via enhanced recrystallization (corresponding to Area 1), followed by occurrences of β precipitation without elemental diffusional partitioning (corresponding to Area 2) and substitution from globular α' grains to ultrafine β subgrains (correponding to Area 3). Thus low temperature aging at 500 °C leads to complicated multimodal structural formation in the fine α' martensite region, and it contibutes to significantly improved strength.

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引用次数: 0

Impact of friction stir welding-like heat cycles on precipitates in AA7050 analysed by SAXS and numerical modelling

IF 3 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-01-22 DOI: 10.1016/j.mtla.2025.102343

Susanne Henninger , Rupesh Chafle , Emad Maawad , Benjamin Klusemann , Martin Müller , Peter Staron

Precipitation kinetics in AA7050 during heat cycles as they occur in friction stir welding (FSW) were studied via small-angle X-ray scattering (SAXS), X-ray diffraction (XRD) and numerical modelling using the PanPrecipitation software. Reversion experiments were conducted for the calibration of the used model and the reversion stages of dissolution, growth and coarsening of precipitates are successfully modelled. Additionally, reversion experiments on an AA7108 alloy from literature data were modelled, affirming that other AA7xxx alloys can be described with the developed model as well. The model was used to predict precipitation kinetics in AA7050-T7451 during heat cycles typically occurring in FSW, enabling the prediction of the evolution of volume fraction and precipitate size distribution of

η

-precipitates at elevated temperatures, matching experimental results. For instance, with increasing temperature, stronger coarsening as well as lower final volume fractions are expected. Finally, the influence of maximum temperature and welding speed on the precipitate size distribution was studied, providing guidelines for temperature-driven process design.

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引用次数: 0