Pub Date : 2025-12-01Epub Date: 2025-09-27DOI: 10.1016/j.mtla.2025.102561
Yoon-Gu Lee , Hongik Kim , Junhyeok Hyun , Jaehee Sohn , Jae-Min Lim , Da-Young Lee , Young-Chang Joo , So-Yeon Lee
Ruthenium (Ru) is a promising material for next-generation semiconductor interconnects because of its low resistivity scaling and robust electrical reliability. Since Ru lines are patterned from thin films, understanding the relationship between film microstructure and physical properties is essential. This study investigated how grain size measurement methodology influences the correlation between microstructure and two key properties—resistivity and growth stress—in Ru films. Grain size was evaluated via the circle equivalence method (CEM) and linear intercept method (LIM) for as-deposited and annealed films. The results revealed that the optimal grain size metric depends on grain morphology as well as distribution skewness. The LIM better captured the properties of as-deposited films with highly skewed distributions, whereas the CEM was better for annealed films with symmetric distributions. These findings highlight the need to consider distribution characteristics when selecting grain size metrics, offering a framework for accurate property prediction in high-melting-point interconnect metals.
{"title":"A distribution-dependent grain size measurement for the accurate property prediction of ruthenium interconnects","authors":"Yoon-Gu Lee , Hongik Kim , Junhyeok Hyun , Jaehee Sohn , Jae-Min Lim , Da-Young Lee , Young-Chang Joo , So-Yeon Lee","doi":"10.1016/j.mtla.2025.102561","DOIUrl":"10.1016/j.mtla.2025.102561","url":null,"abstract":"<div><div>Ruthenium (Ru) is a promising material for next-generation semiconductor interconnects because of its low resistivity scaling and robust electrical reliability. Since Ru lines are patterned from thin films, understanding the relationship between film microstructure and physical properties is essential. This study investigated how grain size measurement methodology influences the correlation between microstructure and two key properties—resistivity and growth stress—in Ru films. Grain size was evaluated via the circle equivalence method (CEM) and linear intercept method (LIM) for as-deposited and annealed films. The results revealed that the optimal grain size metric depends on grain morphology as well as distribution skewness. The LIM better captured the properties of as-deposited films with highly skewed distributions, whereas the CEM was better for annealed films with symmetric distributions. These findings highlight the need to consider distribution characteristics when selecting grain size metrics, offering a framework for accurate property prediction in high-melting-point interconnect metals.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102561"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525458","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}
Pub Date : 2025-12-01Epub Date: 2025-09-07DOI: 10.1016/j.mtla.2025.102548
Bo Yang , Shuang Liang , Hongtao Han , Yuesheng Majia , Jiaheng Zhang , Gang Zhao , Chengyu Wu
To address the challenge of poor intradermal penetration of hyaluronic acid (HA), researchers applied deep eutectic solvent (DES) technology within a drug delivery system. In this study, supramolecular HA nanoparticles (Supra HA) were successfully prepared by combining HA and decanoic acid-menthol deep eutectic solvent (DAM-DES). The resulting Supra HA nanoparticles exhibited an average particle size of 124 nm and a zeta potential of -35 mV. The intradermal penetration efficacy of Supra HA was 2.26 times greater than that of GTCC HA. Furthermore, Supra HA significantly increased type I collagen synthesis in fibroblasts by 54.0 % and reduced MMP-1 secretion by 57.4 %, demonstrating anti-wrinkle and skin-tightening effects. Under identical conditions, Supra HA enhanced the synthesis of the FLG gene and AQP3 protein in keratinocytes by 55 % and 227.4 %, respectively, indicating skin barrier repair and moisturizing effects. Human clinical trials demonstrated that 28-day application of Supra HA significantly enhanced skin hydration (13.3 % increace), with concurrent improvements in skin elasticity (21.3 % increase), firmness (21.9 % elevation), and wrinkle reduction (20.1 % decrease in count and 23.3 % reduction in area). Collectively, these findings indicate that the utilization of deep eutectic solvents in hyaluronic acid delivery systems facilitates transdermal permeation, thereby contributing to sustained moisturization and anti-aging efficacy.
{"title":"Deep eutectic solvent nanoparticles for enhanced hyaluronic acid intradermal delivery: Anti-aging and moisturizing effects","authors":"Bo Yang , Shuang Liang , Hongtao Han , Yuesheng Majia , Jiaheng Zhang , Gang Zhao , Chengyu Wu","doi":"10.1016/j.mtla.2025.102548","DOIUrl":"10.1016/j.mtla.2025.102548","url":null,"abstract":"<div><div>To address the challenge of poor intradermal penetration of hyaluronic acid (HA), researchers applied deep eutectic solvent (DES) technology within a drug delivery system. In this study, supramolecular HA nanoparticles (Supra HA) were successfully prepared by combining HA and decanoic acid-menthol deep eutectic solvent (DAM-DES). The resulting Supra HA nanoparticles exhibited an average particle size of 124 nm and a zeta potential of -35 mV. The intradermal penetration efficacy of Supra HA was 2.26 times greater than that of GTCC HA. Furthermore, Supra HA significantly increased type I collagen synthesis in fibroblasts by 54.0 % and reduced MMP-1 secretion by 57.4 %, demonstrating anti-wrinkle and skin-tightening effects. Under identical conditions, Supra HA enhanced the synthesis of the FLG gene and AQP3 protein in keratinocytes by 55 % and 227.4 %, respectively, indicating skin barrier repair and moisturizing effects. Human clinical trials demonstrated that 28-day application of Supra HA significantly enhanced skin hydration (13.3 % increace), with concurrent improvements in skin elasticity (21.3 % increase), firmness (21.9 % elevation), and wrinkle reduction (20.1 % decrease in count and 23.3 % reduction in area). Collectively, these findings indicate that the utilization of deep eutectic solvents in hyaluronic acid delivery systems facilitates transdermal permeation, thereby contributing to sustained moisturization and anti-aging efficacy.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102548"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049545","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}
<div><div>Grain-boundary-limited charge transport is a fundamental bottleneck in polycrystalline thermoelectric materials, where reduced carrier mobility degrades electrical conductivity and suppresses power factors. This degradation arises from the interplay of scattering mechanisms: grain-boundary barriers dominate at low temperatures; thermionic activation enables partial barrier crossing at intermediate temperatures; and phonon scattering limits the mean free path at high temperatures. Hence, there remains a need for a physically transparent framework to quantitatively extract these microstructural parameters. In this study, a semi-empirical mobility model that explicitly integrates these grain-boundary mechanisms was developed and validated, expressed as: <span><math><mrow><msub><mi>μ</mi><mrow><mi>e</mi><mi>f</mi><mi>f</mi></mrow></msub><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><msub><mi>μ</mi><mi>w</mi></msub><mtext>exp</mtext><mrow><mo>(</mo><mrow><mo>−</mo><mfrac><msub><mstyle><mi>Φ</mi></mstyle><mrow><mi>G</mi><mi>B</mi></mrow></msub><mrow><msub><mi>k</mi><mi>B</mi></msub><mi>T</mi></mrow></mfrac></mrow><mo>)</mo></mrow><mfrac><mrow><mi>l</mi><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mrow><mi>l</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mo>+</mo><msub><mi>w</mi><mrow><mi>G</mi><mi>B</mi></mrow></msub></mrow></mfrac></mrow></math></span> where <span><math><msub><mi>μ</mi><mi>w</mi></msub></math></span> is the weighted mobility, <span><math><msub><mstyle><mi>Φ</mi></mstyle><mrow><mi>G</mi><mi>B</mi></mrow></msub></math></span> is the grain‑boundary barrier height, <span><math><msub><mi>k</mi><mi>B</mi></msub></math></span> is Boltzmann’s constant, <span><math><mi>T</mi></math></span> is temperature, <span><math><mrow><mi>l</mi><mo>(</mo><mi>T</mi><mo>)</mo></mrow></math></span> is the bulk mean free path and <span><math><msub><mi>w</mi><mrow><mi>G</mi><mi>B</mi></mrow></msub></math></span> is the boundary width. This model was validated for oxide semiconductor, intermetallic, chalcogenide and heuslers polycrystalline materials, achieving excellent agreement with experimental data (<span><math><msup><mrow><mi>R</mi></mrow><mn>2</mn></msup></math></span>= 0.97–0.99) and yielding physically consistent parameters: <span><math><msub><mstyle><mi>Φ</mi></mstyle><mrow><mi>G</mi><mi>B</mi></mrow></msub></math></span> ≈ 0–0.056 eV and <span><math><msub><mi>l</mi><mn>300</mn></msub></math></span> ≈ 6–368 nm. A case study for Ta doped ZnO thermoelectric material shows that barrier passivation (reduction of <span><math><msub><mstyle><mi>Φ</mi></mstyle><mrow><mi>G</mi><mi>B</mi></mrow></msub></math></span> from 0.056 eV to 0.03 eV) combined with modest grain-interior improvement (<span><math><msub><mi>l</mi><mn>300</mn></msub></math></span>→60 nm) can significantly enhance carrier mobility across the entire temperature range. The analysis predicts that, at ∼1000 K, grain engineering could nearly double mobility and electrical conductivity.
{"title":"Unified mobility model for grain‑boundary‑limited transport in polycrystalline thermoelectric materials","authors":"Gbadebo Taofeek Yusuf , Sukhwinder Singh , Alexandros Askounis , Zlatka Stoeva , Fideline Tchuenbou-Magaia","doi":"10.1016/j.mtla.2025.102550","DOIUrl":"10.1016/j.mtla.2025.102550","url":null,"abstract":"<div><div>Grain-boundary-limited charge transport is a fundamental bottleneck in polycrystalline thermoelectric materials, where reduced carrier mobility degrades electrical conductivity and suppresses power factors. This degradation arises from the interplay of scattering mechanisms: grain-boundary barriers dominate at low temperatures; thermionic activation enables partial barrier crossing at intermediate temperatures; and phonon scattering limits the mean free path at high temperatures. Hence, there remains a need for a physically transparent framework to quantitatively extract these microstructural parameters. In this study, a semi-empirical mobility model that explicitly integrates these grain-boundary mechanisms was developed and validated, expressed as: <span><math><mrow><msub><mi>μ</mi><mrow><mi>e</mi><mi>f</mi><mi>f</mi></mrow></msub><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><msub><mi>μ</mi><mi>w</mi></msub><mtext>exp</mtext><mrow><mo>(</mo><mrow><mo>−</mo><mfrac><msub><mstyle><mi>Φ</mi></mstyle><mrow><mi>G</mi><mi>B</mi></mrow></msub><mrow><msub><mi>k</mi><mi>B</mi></msub><mi>T</mi></mrow></mfrac></mrow><mo>)</mo></mrow><mfrac><mrow><mi>l</mi><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mrow><mi>l</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow><mo>+</mo><msub><mi>w</mi><mrow><mi>G</mi><mi>B</mi></mrow></msub></mrow></mfrac></mrow></math></span> where <span><math><msub><mi>μ</mi><mi>w</mi></msub></math></span> is the weighted mobility, <span><math><msub><mstyle><mi>Φ</mi></mstyle><mrow><mi>G</mi><mi>B</mi></mrow></msub></math></span> is the grain‑boundary barrier height, <span><math><msub><mi>k</mi><mi>B</mi></msub></math></span> is Boltzmann’s constant, <span><math><mi>T</mi></math></span> is temperature, <span><math><mrow><mi>l</mi><mo>(</mo><mi>T</mi><mo>)</mo></mrow></math></span> is the bulk mean free path and <span><math><msub><mi>w</mi><mrow><mi>G</mi><mi>B</mi></mrow></msub></math></span> is the boundary width. This model was validated for oxide semiconductor, intermetallic, chalcogenide and heuslers polycrystalline materials, achieving excellent agreement with experimental data (<span><math><msup><mrow><mi>R</mi></mrow><mn>2</mn></msup></math></span>= 0.97–0.99) and yielding physically consistent parameters: <span><math><msub><mstyle><mi>Φ</mi></mstyle><mrow><mi>G</mi><mi>B</mi></mrow></msub></math></span> ≈ 0–0.056 eV and <span><math><msub><mi>l</mi><mn>300</mn></msub></math></span> ≈ 6–368 nm. A case study for Ta doped ZnO thermoelectric material shows that barrier passivation (reduction of <span><math><msub><mstyle><mi>Φ</mi></mstyle><mrow><mi>G</mi><mi>B</mi></mrow></msub></math></span> from 0.056 eV to 0.03 eV) combined with modest grain-interior improvement (<span><math><msub><mi>l</mi><mn>300</mn></msub></math></span>→60 nm) can significantly enhance carrier mobility across the entire temperature range. The analysis predicts that, at ∼1000 K, grain engineering could nearly double mobility and electrical conductivity. ","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102550"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049546","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}
Pub Date : 2025-12-01Epub Date: 2025-09-05DOI: 10.1016/j.mtla.2025.102545
Kevin Gautier , Antoine Casadebaigt , Emilie Fourcade , Enrica Epifano , Tripti Gaur , Aurélie Vande Put , Daniel Monceau
The precise quantification of oxygen concentration in titanium is crucial for various high-performance applications. In this study, we developed reference samples to calibrate high-resolution micro laser-induced breakdown spectroscopy (HR-µLIBS) for oxygen analysis in titanium. Two fabrication methods were employed: (i) oxidation of titanium powder at high temperature in a controlled atmosphere with oxygen, followed by spark plasma sintering (SPS), and (ii) blending titanium powder with TiO2 powder before sintering by SPS. Homogenized samples were then used to establish a calibration line correlating HR-µLIBS intensity with known oxygen concentrations. To evaluate the HR-µLIBS method, a titanium sample oxidized 500 h at 650 °C in Ar-20 %O2 was analyzed using both HR-µLIBS and electron probe microanalysis (EPMA). The results demonstrate a strong agreement between the two methods, with HR-µLIBS offering superior speed and improved accuracy at low oxygen concentrations (< 3 at. %).
钛中氧浓度的精确定量对各种高性能应用至关重要。在这项研究中，我们开发了参考样品来校准用于钛中氧分析的高分辨率微激光诱导击穿光谱（HR-µLIBS）。采用两种制备方法：(1)在可控气氛下用氧气高温氧化钛粉，然后进行放电等离子烧结（SPS）；(2)在SPS烧结前将钛粉与TiO2粉混合。然后使用均匀的样品建立HR-µLIBS强度与已知氧浓度相关的校准线。为了评估HR-µLIBS方法，使用HR-µLIBS和电子探针微量分析（EPMA）对钛样品在650°C ar - 20% O2中氧化500 h进行分析。结果表明两种方法之间具有很强的一致性，HR-µLIBS在低氧浓度（< 3 at）下提供了卓越的速度和更高的准确性。%)。
{"title":"Development and application of high-purity Ti-O reference alloys for oxygen quantification using high resolution micro laser induced breakdown spectroscopy (HR-µLIBS)","authors":"Kevin Gautier , Antoine Casadebaigt , Emilie Fourcade , Enrica Epifano , Tripti Gaur , Aurélie Vande Put , Daniel Monceau","doi":"10.1016/j.mtla.2025.102545","DOIUrl":"10.1016/j.mtla.2025.102545","url":null,"abstract":"<div><div>The precise quantification of oxygen concentration in titanium is crucial for various high-performance applications. In this study, we developed reference samples to calibrate high-resolution micro laser-induced breakdown spectroscopy (HR-µLIBS) for oxygen analysis in titanium. Two fabrication methods were employed: (i) oxidation of titanium powder at high temperature in a controlled atmosphere with oxygen, followed by spark plasma sintering (SPS), and (ii) blending titanium powder with TiO<sub>2</sub> powder before sintering by SPS. Homogenized samples were then used to establish a calibration line correlating HR-µLIBS intensity with known oxygen concentrations. To evaluate the HR-µLIBS method, a titanium sample oxidized 500 h at 650 °C in Ar-20 %O<sub>2</sub> was analyzed using both HR-µLIBS and electron probe microanalysis (EPMA). The results demonstrate a strong agreement between the two methods, with HR-µLIBS offering superior speed and improved accuracy at low oxygen concentrations (< 3 at. %).</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102545"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049547","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}
Pub Date : 2025-12-01Epub Date: 2025-10-31DOI: 10.1016/j.mtla.2025.102593
Panpan Xu, Wentao Hao, Xiaole Qiu, Ensi Cao, Bing Sun
Bi-doped (In,Nb)TiO2 ceramics with nominal composition (Bi0.1In0.4Nb0.5)0.1Ti0.9O2 were synthesized to mitigate the high low-frequency dielectric losses present in undoped counterparts. The incorporation of Bi2O3 as a sintering aid significantly enhanced densification and effectively reduced the sintering temperature. Bi doping resulted in grain size refinement to 4.18–8.38 μm, increased the grain boundary area density, and facilitated the formation of insulating Bi2Ti2O7 secondary phases at the grain boundaries. These structural modifications decreased the low-frequency dielectric loss from over 0.1 to below 0.05, with a minimum of 0.042 at 300 Hz, while preserving the colossal permittivity. A novel dielectric relaxation phenomenon near 100 kHz was observed, which is explicitly attributed to Maxwell-Wagner interfacial polarization at the boundaries between semiconducting grains and insulating Bi2Ti2O7 secondary phases. Complex impedance analysis revealed that the enhanced grain boundary resistance was the primary factor responsible for the reduction in dielectric loss. XPS confirmed the coexistence of Ti3+/Ti4+ oxidation states and oxygen vacancies, indicating that the colossal permittivity originated from a combination of electron-pinned defect dipole behavior and internal barrier layer capacitor mechanisms.
{"title":"Synergistic grain boundary engineering and insulating phase formation for low-loss colossal permittivity in Bi-doped (In,Nb)TiO2 ceramics","authors":"Panpan Xu, Wentao Hao, Xiaole Qiu, Ensi Cao, Bing Sun","doi":"10.1016/j.mtla.2025.102593","DOIUrl":"10.1016/j.mtla.2025.102593","url":null,"abstract":"<div><div>Bi-doped (In,Nb)TiO<sub>2</sub> ceramics with nominal composition (Bi<sub>0.1</sub>In<sub>0.4</sub>Nb<sub>0.5</sub>)<sub>0.1</sub>Ti<sub>0.9</sub>O<sub>2</sub> were synthesized to mitigate the high low-frequency dielectric losses present in undoped counterparts. The incorporation of Bi<sub>2</sub>O<sub>3</sub> as a sintering aid significantly enhanced densification and effectively reduced the sintering temperature. Bi doping resulted in grain size refinement to 4.18–8.38 μm, increased the grain boundary area density, and facilitated the formation of insulating Bi<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> secondary phases at the grain boundaries. These structural modifications decreased the low-frequency dielectric loss from over 0.1 to below 0.05, with a minimum of 0.042 at 300 Hz, while preserving the colossal permittivity. A novel dielectric relaxation phenomenon near 100 kHz was observed, which is explicitly attributed to Maxwell-Wagner interfacial polarization at the boundaries between semiconducting grains and insulating Bi<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub> secondary phases. Complex impedance analysis revealed that the enhanced grain boundary resistance was the primary factor responsible for the reduction in dielectric loss. XPS confirmed the coexistence of Ti<sup>3+</sup>/Ti<sup>4+</sup> oxidation states and oxygen vacancies, indicating that the colossal permittivity originated from a combination of electron-pinned defect dipole behavior and internal barrier layer capacitor mechanisms.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102593"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474176","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}
Pub Date : 2025-12-01Epub Date: 2025-09-08DOI: 10.1016/j.mtla.2025.102549
Peng Gong , Josh Chuter , Xingzhong Liang , Tung L. Lee , Richard Birley , Dongchen Hu , Ed Pickering , Philip J. Withers , W Mark Rainforth
Recent studies show that precipitate-strengthened microalloyed steels offer strong resistance to hydrogen embrittlement due to hydrogen trapping by nanoscale precipitates. This study investigates how these precipitates interact with dislocations under strain, simulating service conditions. Two model steels were used: Ti-Mo steel with coherent (Ti,Mo)C precipitates and V-Mo steel with semi-coherent (V,Mo)C precipitates. Dislocation density was measured during in-situ neutron diffraction tensile tests, with and without hydrogen charging. Hydrogen increased dislocation density before straining but suppressed dislocation multiplication during loading, reducing overall dislocation strengthening, especially in Ti-Mo steel. The Ti-Mo steel showed greater sensitivity to hydrogen, attributed to reversible hydrogen trapping at coherent precipitate interfaces, and a greater increase in dislocation density. In contrast, V-Mo steel exhibited more irreversible trapping and a smaller increase in dislocation density. During tensile testing, with reversible hydrogen released to diffuse, subgrain formation in Ti-Mo steel was restricted, as the higher concentration of diffusible hydrogen suppressed screw dislocation mobility. Consequently, fewer subgrain microstructures were generated, diminishing their effectiveness as barriers to crack propagation in Ti-Mo steel, compared to V-Mo steel. These results highlight the importance of selecting precipitate types that enhance irreversible hydrogen trapping, thereby improving the hydrogen resistance of steels.
{"title":"Effect of hydrogen on deformation behavior in Ti-Mo and V-Mo precipitate-strengthened steels","authors":"Peng Gong , Josh Chuter , Xingzhong Liang , Tung L. Lee , Richard Birley , Dongchen Hu , Ed Pickering , Philip J. Withers , W Mark Rainforth","doi":"10.1016/j.mtla.2025.102549","DOIUrl":"10.1016/j.mtla.2025.102549","url":null,"abstract":"<div><div>Recent studies show that precipitate-strengthened microalloyed steels offer strong resistance to hydrogen embrittlement due to hydrogen trapping by nanoscale precipitates. This study investigates how these precipitates interact with dislocations under strain, simulating service conditions. Two model steels were used: Ti-Mo steel with coherent (Ti,Mo)C precipitates and V-Mo steel with semi-coherent (V,Mo)C precipitates. Dislocation density was measured during in-situ neutron diffraction tensile tests, with and without hydrogen charging. Hydrogen increased dislocation density before straining but suppressed dislocation multiplication during loading, reducing overall dislocation strengthening, especially in Ti-Mo steel. The Ti-Mo steel showed greater sensitivity to hydrogen, attributed to reversible hydrogen trapping at coherent precipitate interfaces, and a greater increase in dislocation density. In contrast, V-Mo steel exhibited more irreversible trapping and a smaller increase in dislocation density. During tensile testing, with reversible hydrogen released to diffuse, subgrain formation in Ti-Mo steel was restricted, as the higher concentration of diffusible hydrogen suppressed screw dislocation mobility. Consequently, fewer subgrain microstructures were generated, diminishing their effectiveness as barriers to crack propagation in Ti-Mo steel, compared to V-Mo steel. These results highlight the importance of selecting precipitate types that enhance irreversible hydrogen trapping, thereby improving the hydrogen resistance of steels.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102549"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106319","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}
Pub Date : 2025-12-01Epub Date: 2025-10-22DOI: 10.1016/j.mtla.2025.102587
Divya Sri Bandla , Atul H. Chokshi
Concentrated solid solution alloys such as NiCoCr and NiCoCrFe are well known for their low stacking fault energies and promising mechanical properties at low temperatures. However, their high temperature deformation has not been well established. The present study deals with the high temperature creep behavior of these alloys. Both alloys had a single phase solid solution with FCC crystal structure which was not altered by creep deformation. The room temperature stacking fault energies of NiCoCr and NiCoCrFe alloys were evaluated to be in the range of 14 – 27 mJ m−2 and 11 – 26 mJ m−2, respectively. The dominating creep mechanism in these alloys at 990 K was observed to be dislocation climb and there was no significant difference in the creep rates of alloys. The creep deformation resulted in a planar band structure in both alloys. Despite multiple principal elements in NiCoCr and NiCoCrFe alloys, the atomic misfit parameters of these alloys were calculated to be low which resulted in poor solute drag influence on the dislocation climb as compared to vacancy diffusion. A comparison between the creep rates of NiCoCr and NiCoCrFe alloys from the present study with that of a binary Ni – 60 Co system which had a similar room temperature stacking fault energy revealed significantly lower creep rates in NiCoCr and NiCoCrFe alloys.
{"title":"Insights into the creep behavior of Ni based concentrated solid solution alloys","authors":"Divya Sri Bandla , Atul H. Chokshi","doi":"10.1016/j.mtla.2025.102587","DOIUrl":"10.1016/j.mtla.2025.102587","url":null,"abstract":"<div><div>Concentrated solid solution alloys such as NiCoCr and NiCoCrFe are well known for their low stacking fault energies and promising mechanical properties at low temperatures. However, their high temperature deformation has not been well established. The present study deals with the high temperature creep behavior of these alloys. Both alloys had a single phase solid solution with FCC crystal structure which was not altered by creep deformation. The room temperature stacking fault energies of NiCoCr and NiCoCrFe alloys were evaluated to be in the range of 14 – 27 mJ m<sup>−2</sup> and 11 – 26 mJ m<sup>−2</sup>, respectively. The dominating creep mechanism in these alloys at 990 K was observed to be dislocation climb and there was no significant difference in the creep rates of alloys. The creep deformation resulted in a planar band structure in both alloys. Despite multiple principal elements in NiCoCr and NiCoCrFe alloys, the atomic misfit parameters of these alloys were calculated to be low which resulted in poor solute drag influence on the dislocation climb as compared to vacancy diffusion. A comparison between the creep rates of NiCoCr and NiCoCrFe alloys from the present study with that of a binary Ni – 60 Co system which had a similar room temperature stacking fault energy revealed significantly lower creep rates in NiCoCr and NiCoCrFe alloys.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102587"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416585","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}
Pub Date : 2025-12-01Epub Date: 2025-09-27DOI: 10.1016/j.mtla.2025.102565
Sajad Shirzad , Ali Kassab , Apratim Chakraborty , Christopher Pannier , Zhen Hu , Georges Ayoub , Pravansu Mohanty
Metal Paste Deposition is an emerging additive manufacturing method that extrudes metal paste to form green parts, which are subsequently sintered for densification. This study investigates the influence of infill pattern on the macro- and microstructural properties of sintered 316 L stainless steel parts. Comprehensive experimental characterization, including porosity analysis, grain size measurement, phase identification, 3D scanning, and nanohardness testing, was conducted across multiple surfaces and regions. Results revealed that porosity and elastic modulus varied with both infill geometry and local position. Grain size remained consistent across all patterns and locations, averaging ∼50 µm. Nanoindentation measurements revealed that hardness values remained within the expected range for 316 L stainless steel (2.6–4.5 GPa), showing minimal variation across different regions. Pores were predominantly circular, with circularity values ranging from 0.96 to 0.99, suggesting effective surface-energy-driven densification. Among all tested patterns, the “grid” infill pattern achieved the highest densification and stiffness due to increased bead overlap. A bead-level finite element simulation, using reconstructed geometries from G-code, captured localized shrinkage, porosity evolution, and grain growth trends, showing good agreement with experiments. These results validate the simulation framework and highlight the importance of infill design in optimizing part performance and reliability. All findings reported here are specific to parts fabricated at 50% nominal infill density and processed under the studied sintering conditions (12 h cycle with 4 h hold at 1380°C).
{"title":"Influence of infill architecture on shrinkage, microstructure, and mechanical properties in paste extrusion 3D printed stainless steel","authors":"Sajad Shirzad , Ali Kassab , Apratim Chakraborty , Christopher Pannier , Zhen Hu , Georges Ayoub , Pravansu Mohanty","doi":"10.1016/j.mtla.2025.102565","DOIUrl":"10.1016/j.mtla.2025.102565","url":null,"abstract":"<div><div>Metal Paste Deposition is an emerging additive manufacturing method that extrudes metal paste to form green parts, which are subsequently sintered for densification. This study investigates the influence of infill pattern on the macro- and microstructural properties of sintered 316 L stainless steel parts. Comprehensive experimental characterization, including porosity analysis, grain size measurement, phase identification, 3D scanning, and nanohardness testing, was conducted across multiple surfaces and regions. Results revealed that porosity and elastic modulus varied with both infill geometry and local position. Grain size remained consistent across all patterns and locations, averaging ∼50 µm. Nanoindentation measurements revealed that hardness values remained within the expected range for 316 L stainless steel (2.6–4.5 GPa), showing minimal variation across different regions. Pores were predominantly circular, with circularity values ranging from 0.96 to 0.99, suggesting effective surface-energy-driven densification. Among all tested patterns, the “grid” infill pattern achieved the highest densification and stiffness due to increased bead overlap. A bead-level finite element simulation, using reconstructed geometries from G-code, captured localized shrinkage, porosity evolution, and grain growth trends, showing good agreement with experiments. These results validate the simulation framework and highlight the importance of infill design in optimizing part performance and reliability. All findings reported here are specific to parts fabricated at 50% nominal infill density and processed under the studied sintering conditions (12 h cycle with 4 h hold at 1380°C).</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102565"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220863","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}
Pub Date : 2025-12-01Epub Date: 2025-11-07DOI: 10.1016/j.mtla.2025.102599
E.C. Galliopoulou , S. He , G.T. Martinez , H. Shang , C. Jones , M. Zimina , J. Siefert , J.D. Parker , G.M. Hughes , A. Cocks , T.L. Martin
Creep cavity formation in Grade 91 steel components is a serious challenge that energy applications face, as cavities grow, coalesce, form propagating cracks and eventually lead to failure. This study investigates the microstructural parameters associated with creep cavity nucleation in ex-service martensitic P91 material. Three uniaxial and one double-notched creep tested samples were investigated, interrupted at 0.5 % and 1 % and failed at 3.7 % strain fractions, in order to inspect the evolution of damage in early and late stages of the creep life. A correlative SEM-EBSD technique was employed, revealing that most cavities nucleated along the parent austenite grain boundary (PAGB) structure, with grain boundary junctions exhibiting increased susceptibility to damage. Although PAGBs with misorientation angles of 15–35° and 60° were not the predominant boundary type in the parent microstructure, they exhibited high cavitation ratios. Manganese sulfide (MnS) inclusions were found to be highly prone to cavity nucleation, while smaller precipitates, such as M23C6 carbides, Laves phase and MX-type nitrides, facilitated cavity formation at the MnS/martensite matrix interface. Since the vast majority of grains were soft, no clear correlation between the Schmid Factor and cavitation could be established.
{"title":"Microstructural parameters associated with cavity nucleation in martensitic Grade 91 steel under creep conditions","authors":"E.C. Galliopoulou , S. He , G.T. Martinez , H. Shang , C. Jones , M. Zimina , J. Siefert , J.D. Parker , G.M. Hughes , A. Cocks , T.L. Martin","doi":"10.1016/j.mtla.2025.102599","DOIUrl":"10.1016/j.mtla.2025.102599","url":null,"abstract":"<div><div>Creep cavity formation in Grade 91 steel components is a serious challenge that energy applications face, as cavities grow, coalesce, form propagating cracks and eventually lead to failure. This study investigates the microstructural parameters associated with creep cavity nucleation in ex-service martensitic P91 material. Three uniaxial and one double-notched creep tested samples were investigated, interrupted at 0.5 % and 1 % and failed at 3.7 % strain fractions, in order to inspect the evolution of damage in early and late stages of the creep life. A correlative SEM-EBSD technique was employed, revealing that most cavities nucleated along the parent austenite grain boundary (PAGB) structure, with grain boundary junctions exhibiting increased susceptibility to damage. Although PAGBs with misorientation angles of 15–35° and 60° were not the predominant boundary type in the parent microstructure, they exhibited high cavitation ratios. Manganese sulfide (MnS) inclusions were found to be highly prone to cavity nucleation, while smaller precipitates, such as M<sub>23</sub>C<sub>6</sub> carbides, Laves phase and MX-type nitrides, facilitated cavity formation at the MnS/martensite matrix interface. Since the vast majority of grains were soft, no clear correlation between the Schmid Factor and cavitation could be established.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102599"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525453","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}
Pub Date : 2025-12-01Epub Date: 2025-10-17DOI: 10.1016/j.mtla.2025.102583
R. Holdsworth , J.K. Yee , D. Apelian , E. Lavernia , A.F. Jankowski
Recently, the application of a constitutive mechanical property parameter cb has been demonstrated to model mechanical properties in additively manufactured alloys. The parameter represents a quantifiable assessment for the amount of plasticity between the yield point and the onset of instability. Characterization of these parameters is not trivial due to the signal noise that is typically present in tensile data. An analysis of the methodology for an open-source code to determine cb values is presented and its application is illustrated using an additively manufactured 304 L stainless steel dataset as produced through laser powder bed fusion and subjected to accelerated aging conditions. The ability to standardize the application of this model to experimental data will allow for broader materials qualification and performance evaluation.
{"title":"Development and use of an automated method for calculating constitutive mechanical property parameter Cb","authors":"R. Holdsworth , J.K. Yee , D. Apelian , E. Lavernia , A.F. Jankowski","doi":"10.1016/j.mtla.2025.102583","DOIUrl":"10.1016/j.mtla.2025.102583","url":null,"abstract":"<div><div>Recently, the application of a constitutive mechanical property parameter c<sub>b</sub> has been demonstrated to model mechanical properties in additively manufactured alloys. The parameter represents a quantifiable assessment for the amount of plasticity between the yield point and the onset of instability. Characterization of these parameters is not trivial due to the signal noise that is typically present in tensile data. An analysis of the methodology for an open-source code to determine c<sub>b</sub> values is presented and its application is illustrated using an additively manufactured 304 L stainless steel dataset as produced through laser powder bed fusion and subjected to accelerated aging conditions. The ability to standardize the application of this model to experimental data will allow for broader materials qualification and performance evaluation.</div></div>","PeriodicalId":47623,"journal":{"name":"Materialia","volume":"44 ","pages":"Article 102583"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362434","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}
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