Inserting a Teflon tape between a relaxed sample of a Zr50Cu40Al10 metallic glass and a loading platen resulted in the emergence of a plastic strain of 1.5%–2% under compression. We determined the origin of plasticity from the evolution of the local internal strain/stress state (i.e., the local mechanical state) during compression. A real-time observation of the strain state by a digital image correlation (DIC) analysis revealed a large longitudinal-to-lateral strain ratio (–εxx/εyy) near the contact area, suggesting that the Teflon tape enabled expansion of this region. A finite element method (FEM) analysis confirmed this hypothesis. The DIC analysis revealed the appearance of multiple shear bands, which were initiated in regions that were identified as yielding areas under the expansion contact condition in the FEM analysis. The induced inhomogeneous strain/stress distribution retarded the immediate penetration of shear bands/cracks, which may have led to the emergence of global plasticity.
{"title":"Reduction of lateral constrain leads to plasticity in metallic glasses","authors":"Rui Yamada , Keisuke Tabaru , Ryota Maeda , Wook Ha Ryu , Junji Saida","doi":"10.1016/j.scriptamat.2026.117165","DOIUrl":"10.1016/j.scriptamat.2026.117165","url":null,"abstract":"<div><div>Inserting a Teflon tape between a relaxed sample of a Zr<sub>50</sub>Cu<sub>40</sub>Al<sub>10</sub> metallic glass and a loading platen resulted in the emergence of a plastic strain of 1.5%–2% under compression. We determined the origin of plasticity from the evolution of the local internal strain/stress state (i.e., the local mechanical state) during compression. A real-time observation of the strain state by a digital image correlation (DIC) analysis revealed a large longitudinal-to-lateral strain ratio (–ε<sub>xx</sub>/ε<sub>yy</sub>) near the contact area, suggesting that the Teflon tape enabled expansion of this region. A finite element method (FEM) analysis confirmed this hypothesis. The DIC analysis revealed the appearance of multiple shear bands, which were initiated in regions that were identified as yielding areas under the expansion contact condition in the FEM analysis. The induced inhomogeneous strain/stress distribution retarded the immediate penetration of shear bands/cracks, which may have led to the emergence of global plasticity.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"276 ","pages":"Article 117165"},"PeriodicalIF":5.6,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-15Epub Date: 2026-01-31DOI: 10.1016/j.scriptamat.2026.117193
Zhenyu Wang , Kan Ma , Bowen Shi , Yuanfei Su , Tongzhao Gong , Xianbo Shi , Quanqiang Shi , Wei Wang , Wei Yan
Grain refinement via austenite reversion has been a critical process in maraging steels; however, Co's governing role in this austenite reversion remains inadequately characterized. This study investigates the influence of Co on the austenite reversion behavior in Fe–Ni–Ti–(Co) maraging steels under continuous heating. We demonstrate that Co inhibits acicular austenite (γA) reversion by elevating its critical Ni concentration threshold. Conversely, Co-induced coarser intergranular Ni₃Ti promotes globular austenite (γG) nucleation. Furthermore, the enhanced γG nucleation results in more pronounced prior austenite grain (PAG) refinement, and the suppression of Co on austenite reversion exacerbates Ni heterogeneity within austenite. Upon subsequent cooling, this chemical heterogeneity triggers an anomalous martensitic transformation, resulting in substantially refinement of the martensitic blocks and packets (MBP). These findings provide fundamental insights into Co-mediated microstructural evolution, establishing new principles for tailoring austenite reversion in ultrahigh strength maraging steels.
{"title":"Harnessing the role of cobalt (Co) on austenite reversion for ultrafine-grained maraging steels","authors":"Zhenyu Wang , Kan Ma , Bowen Shi , Yuanfei Su , Tongzhao Gong , Xianbo Shi , Quanqiang Shi , Wei Wang , Wei Yan","doi":"10.1016/j.scriptamat.2026.117193","DOIUrl":"10.1016/j.scriptamat.2026.117193","url":null,"abstract":"<div><div>Grain refinement via austenite reversion has been a critical process in maraging steels; however, Co's governing role in this austenite reversion remains inadequately characterized. This study investigates the influence of Co on the austenite reversion behavior in Fe–Ni–Ti–(Co) maraging steels under continuous heating. We demonstrate that Co inhibits acicular austenite (γ<sub>A</sub>) reversion by elevating its critical Ni concentration threshold. Conversely, Co-induced coarser intergranular Ni₃Ti promotes globular austenite (γ<sub>G</sub>) nucleation. Furthermore, the enhanced γ<sub>G</sub> nucleation results in more pronounced prior austenite grain (PAG) refinement, and the suppression of Co on austenite reversion exacerbates Ni heterogeneity within austenite. Upon subsequent cooling, this chemical heterogeneity triggers an anomalous martensitic transformation, resulting in substantially refinement of the martensitic blocks and packets (MBP). These findings provide fundamental insights into Co-mediated microstructural evolution, establishing new principles for tailoring austenite reversion in ultrahigh strength maraging steels.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"276 ","pages":"Article 117193"},"PeriodicalIF":5.6,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molybdenum exhibits low solubility in liquid lead-bismuth (LBE) and maintains structural stability at high temperatures, making it a candidate for reactor cladding. However, grain boundaries in crystalline Mo enable LBE penetration. Mo-based amorphous alloys eliminate these boundaries while retaining high thermal stability, potentially providing superior corrosion resistance. Herein, we systematically investigate the corrosion behavior of two Mo-based amorphous alloys, MoCoB and MoCoCrBC, in LBE at 500 °C. The MoCoCrBC exhibits superior corrosion resistance even after prolonged exposure exceeding 2000 h, whereas the MoCoB shows reduced corrosion resistance. Experimental results reveal that the corrosion layer of the MoCoB primarily consists of MoO2, CoMoO4, and PbMoO4. In contrast, the MoCoCrBC forms a continuous and dense Cr2O3 layer on its surface, serving as an effective diffusion barrier that suppresses the penetration of corrosive species into the matrix. These findings provide valuable insights for the development of Mo-based amorphous alloys for LBE environment.
{"title":"High-temperature Mo-based amorphous alloys with enhanced corrosion resistance in lead-bismuth eutectic at 500 °C","authors":"Siming Xiao , Chengquan Zhang , Ya-nan Chen , Chen Su , Pengcheng Zhang , Feifei Zhang , Jijun Yang , Shengfeng Guo","doi":"10.1016/j.scriptamat.2026.117191","DOIUrl":"10.1016/j.scriptamat.2026.117191","url":null,"abstract":"<div><div>Molybdenum exhibits low solubility in liquid lead-bismuth (LBE) and maintains structural stability at high temperatures, making it a candidate for reactor cladding. However, grain boundaries in crystalline Mo enable LBE penetration. Mo-based amorphous alloys eliminate these boundaries while retaining high thermal stability, potentially providing superior corrosion resistance. Herein, we systematically investigate the corrosion behavior of two Mo-based amorphous alloys, MoCoB and MoCoCrBC, in LBE at 500 °C. The MoCoCrBC exhibits superior corrosion resistance even after prolonged exposure exceeding 2000 h, whereas the MoCoB shows reduced corrosion resistance. Experimental results reveal that the corrosion layer of the MoCoB primarily consists of MoO<sub>2</sub>, CoMoO<sub>4</sub>, and PbMoO<sub>4</sub>. In contrast, the MoCoCrBC forms a continuous and dense Cr<sub>2</sub>O<sub>3</sub> layer on its surface, serving as an effective diffusion barrier that suppresses the penetration of corrosive species into the matrix. These findings provide valuable insights for the development of Mo-based amorphous alloys for LBE environment.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"276 ","pages":"Article 117191"},"PeriodicalIF":5.6,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-15Epub Date: 2026-01-31DOI: 10.1016/j.scriptamat.2026.117200
Haijing Li , Xian Dang , Shiqiang Yue , Luozhen Jiang , Zhihua Shen , Zhulin Huang , Haiyan He , Anding Wang
In this study, we investigate the representative equiatomic (Ti0.2Zr0.2Nb0.2Mo0.2Hf0.2)B2 using a combination of multi-shell EXAFS analysis and XANES spectroscopy supported by simulations. EXAFS quantifies the element-resolved bond-length variations (ΔR) and disorder parameters (σ²), revealing a systematic contraction of the M–B bonds for Ti/Zr/Hf and an expansion for Nb/Mo. These opposite responses reflect a balance between atomic-size mismatch and charge redistribution within the MB12 polyhedra. A strong correlation between ΔR(M–B) and ΔR(M–M) further indicates that first-shell distortions propagate into the metal sublattice through a coherent strain field. XANES measurements identify element-specific charge redistribution, while first-principles XANES simulations show that experimental fingerprints are most consistent with local configurations containing mixed low- and high-electronegativity metal pairs, suggesting the presence of XANES-consistent local atomic motifs with element-specific pairing tendencies rather than statistically established ordering.
{"title":"Atomic-scale characterization of local lattice distortion and short-range order in (Ti0.2Zr0.2Nb0.2Mo0.2Hf0.2)B2 revealed by EXAFS and XANES","authors":"Haijing Li , Xian Dang , Shiqiang Yue , Luozhen Jiang , Zhihua Shen , Zhulin Huang , Haiyan He , Anding Wang","doi":"10.1016/j.scriptamat.2026.117200","DOIUrl":"10.1016/j.scriptamat.2026.117200","url":null,"abstract":"<div><div>In this study, we investigate the representative equiatomic (Ti<sub>0.2</sub>Zr<sub>0.2</sub>Nb<sub>0.2</sub>Mo<sub>0.2</sub>Hf<sub>0.2</sub>)B<sub>2</sub> using a combination of multi-shell EXAFS analysis and XANES spectroscopy supported by simulations. EXAFS quantifies the element-resolved bond-length variations (Δ<em>R</em>) and disorder parameters (σ²), revealing a systematic contraction of the M–B bonds for Ti/Zr/Hf and an expansion for Nb/Mo. These opposite responses reflect a balance between atomic-size mismatch and charge redistribution within the MB<sub>12</sub> polyhedra. A strong correlation between Δ<em>R</em>(M–B) and Δ<em>R</em>(M–M) further indicates that first-shell distortions propagate into the metal sublattice through a coherent strain field. XANES measurements identify element-specific charge redistribution, while first-principles XANES simulations show that experimental fingerprints are most consistent with local configurations containing mixed low- and high-electronegativity metal pairs, suggesting the presence of XANES-consistent local atomic motifs with element-specific pairing tendencies rather than statistically established ordering.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"276 ","pages":"Article 117200"},"PeriodicalIF":5.6,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-15Epub Date: 2026-01-28DOI: 10.1016/j.scriptamat.2026.117192
Fei Zhang , Shun Xu , Shiwei Pan , Feng Qian , Lin Yang , Qunbo Fan , Xingwang Cheng
The obstruction of boundaries on propagation of deformation twinning requires accommodation mechanisms with the largest compatibility ability. In this work, two types of localized shear mechanisms acting as incident banding, i.e., β→αʹ martensitic transformation and β→{332} twinning, interact with residual αʹ phase boundary (PB) in Ti-6Mo-3.5Cr-1Zr alloy. Both types of interactions trigger secondary twins inside the residual αʹ phase as accommodation. Surprisingly, the potential twinning variant with the maximum accommodation capacity is not activated, but the one that intersects the PB along a <> direction is frequently preferred. Our analysis indicates that the determination of the preferred mechanism correlates with minimization of the misalignment between the intersection lines of the accommodative twinning plane and the transformation plane of the incident banding with the residual PB. The geometrical feature is important because small misalignment of intersection lines at PB facilitates resultant dislocations dissociation for the nucleation of secondary twins.
{"title":"Phase boundary mediated twinning in stress-induced martensitic bands in metastable Ti-6Mo-3.5Cr-1Zr alloy","authors":"Fei Zhang , Shun Xu , Shiwei Pan , Feng Qian , Lin Yang , Qunbo Fan , Xingwang Cheng","doi":"10.1016/j.scriptamat.2026.117192","DOIUrl":"10.1016/j.scriptamat.2026.117192","url":null,"abstract":"<div><div>The obstruction of boundaries on propagation of deformation twinning requires accommodation mechanisms with the largest compatibility ability. In this work, two types of localized shear mechanisms acting as incident banding, i.e., β→αʹ martensitic transformation and β→{332} twinning, interact with residual αʹ phase boundary (PB) in Ti-6Mo-3.5Cr-1Zr alloy. Both types of interactions trigger secondary <span><math><mrow><mo>{</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>2</mn><mo>}</mo></mrow></math></span> twins inside the residual αʹ phase as accommodation. Surprisingly, the potential <span><math><mrow><mo>{</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>2</mn><mo>}</mo></mrow></math></span> twinning variant with the maximum accommodation capacity is not activated, but the one that intersects the PB along a <<span><math><mrow><mn>11</mn><mover><mn>2</mn><mo>¯</mo></mover><mn>0</mn></mrow></math></span>> direction is frequently preferred. Our analysis indicates that the determination of the preferred mechanism correlates with minimization of the misalignment between the intersection lines of the accommodative twinning plane and the transformation plane of the incident banding with the residual PB. The geometrical feature is important because small misalignment of intersection lines at PB facilitates resultant dislocations dissociation for the nucleation of secondary twins.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"276 ","pages":"Article 117192"},"PeriodicalIF":5.6,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-15Epub Date: 2026-01-27DOI: 10.1016/j.scriptamat.2026.117190
H.W. Hu , Y. Xu , S.Q. Ding , D.X. Zhang , J. Wang , J.Z. Jiang , X.D. Wang , Q.P. Cao
This study reveals an anomalous precipitate evolution mechanism regulated by annealing temperature in an Fe61.5Cr17.5Ni12Al8Ti1 high-entropy alloy. We found that direct quenching after high-temperature annealing at 1273 K can induce a high density of nanoscale, coherent B2-NiAl precipitates (∼50 nm) within the BCC matrix, bypassing the conventional two-step process requiring separate low-temperature aging. The micro-mechanism involves dissolution of precipitates as annealing places the BCC matrix of the alloy in the BCC single-phase region, followed by non-equilibrium precipitation driven by high supersaturation during quenching. In contrast, annealing at 1073–1173 K retains the BCC matrix of the alloy in the BCC+B2 two-phase region, leading solely to precipitate coarsening. This temperature-dependent pathway bifurcation switches the dominant strengthening mechanism from Orowan bypassing to dislocation shearing, elevating the precipitation strengthening contribution to ∼546 MPa and ultimately increasing the alloy's yield strength remarkably to ∼1178 MPa.
{"title":"Anomalous strengthening in Fe-Cr-Ni-Al-Ti high entropy alloy via annealing-induced nanoprecipitate refinement","authors":"H.W. Hu , Y. Xu , S.Q. Ding , D.X. Zhang , J. Wang , J.Z. Jiang , X.D. Wang , Q.P. Cao","doi":"10.1016/j.scriptamat.2026.117190","DOIUrl":"10.1016/j.scriptamat.2026.117190","url":null,"abstract":"<div><div>This study reveals an anomalous precipitate evolution mechanism regulated by annealing temperature in an Fe<sub>61.5</sub>Cr<sub>17.5</sub>Ni<sub>12</sub>Al<sub>8</sub>Ti<sub>1</sub> high-entropy alloy. We found that direct quenching after high-temperature annealing at 1273 K can induce a high density of nanoscale, coherent B2-NiAl precipitates (∼50 nm) within the BCC matrix, bypassing the conventional two-step process requiring separate low-temperature aging. The micro-mechanism involves dissolution of precipitates as annealing places the BCC matrix of the alloy in the BCC single-phase region, followed by non-equilibrium precipitation driven by high supersaturation during quenching. In contrast, annealing at 1073–1173 K retains the BCC matrix of the alloy in the BCC+B2 two-phase region, leading solely to precipitate coarsening. This temperature-dependent pathway bifurcation switches the dominant strengthening mechanism from Orowan bypassing to dislocation shearing, elevating the precipitation strengthening contribution to ∼546 MPa and ultimately increasing the alloy's yield strength remarkably to ∼1178 MPa.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"276 ","pages":"Article 117190"},"PeriodicalIF":5.6,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-15Epub Date: 2026-01-31DOI: 10.1016/j.scriptamat.2026.117196
Amina Tariq , Toqeer Ahmed , Ye Wang , Huayu Yang , Muhammad Sufyan , Wael Ben Taazayet , Houbing Huang , Jing Wang
BiFeO3 films are potential candidate among ferroelectric materials that has been extensively studied and holds significant promise for applications in information storage devices. Growth parameters are key important for the fabrication of the low-dimensional ferroelectric textures, such as charged domain walls, especially when it comes to their deposition via Pulsed Laser Deposition technique. This study investigates the influence of growth temperature on phase structure, morphology, domain/domain wall textures in BiFeO3 thin films grown on a perovskite single-crystal SrTiO3(110) substrate. Crystallinity, strain effect, film thickness and ferroelectric domain/domain walls of BFO thin films were studied using X-ray diffraction, reciprocal space mapping, Scanning electron microscopy and piezoelectric force microscopy, respectively. Comparative analysis of several films grown at distinct temperatures ranging from 520°C-760°C, concludes that the large area of ferroelectric charged domain walls are effectively achieved at optimized growth temperature of 600°C, with the pure structural phase, well-defined strip-like morphology and two domain variants.
{"title":"Large-area engineering of ferroelectric charged domain walls in (110)-oriented BiFeO3 thin films","authors":"Amina Tariq , Toqeer Ahmed , Ye Wang , Huayu Yang , Muhammad Sufyan , Wael Ben Taazayet , Houbing Huang , Jing Wang","doi":"10.1016/j.scriptamat.2026.117196","DOIUrl":"10.1016/j.scriptamat.2026.117196","url":null,"abstract":"<div><div>BiFeO<sub>3</sub> films are potential candidate among ferroelectric materials that has been extensively studied and holds significant promise for applications in information storage devices. Growth parameters are key important for the fabrication of the low-dimensional ferroelectric textures, such as charged domain walls, especially when it comes to their deposition via Pulsed Laser Deposition technique. This study investigates the influence of growth temperature on phase structure, morphology, domain/domain wall textures in BiFeO<sub>3</sub> thin films grown on a perovskite single-crystal SrTiO<sub>3</sub>(110) substrate. Crystallinity, strain effect, film thickness and ferroelectric domain/domain walls of BFO thin films were studied using X-ray diffraction, reciprocal space mapping, Scanning electron microscopy and piezoelectric force microscopy, respectively. Comparative analysis of several films grown at distinct temperatures ranging from 520°C-760°C, concludes that the large area of ferroelectric charged domain walls are effectively achieved at optimized growth temperature of 600°C, with the pure structural phase, well-defined strip-like morphology and two domain variants.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"276 ","pages":"Article 117196"},"PeriodicalIF":5.6,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-15Epub Date: 2026-01-27DOI: 10.1016/j.scriptamat.2026.117187
Maria Kosmidou , Andre Broussard , Conor Galvin , Jie Lian , Erofili Kardoulaki
Creep behavior in uranium nitride (UN) has traditionally been described using the Hayes formulation; however, its fidelity degrades outside narrow stress and temperature bounds. A refined creep model is developed that captures deformation behavior across an extended stress-temperature domain. Newly conducted creep experiments, combined with literature data, facilitated the development of the formulation, which incorporates intrinsic pellet parameters—grain size, impurity content, and theoretical density—and provides an accurate representation of UN’s creep behavior. The model shows good agreement with both new experimental data and values reported in the literature. The proposed expression offers a robust, physically grounded predictive tool for UN performance, suitable for direct implementation in fuel performance and reactor simulation codes.
{"title":"An updated creep formulation for uranium nitride valid across extended stress-temperature domains","authors":"Maria Kosmidou , Andre Broussard , Conor Galvin , Jie Lian , Erofili Kardoulaki","doi":"10.1016/j.scriptamat.2026.117187","DOIUrl":"10.1016/j.scriptamat.2026.117187","url":null,"abstract":"<div><div>Creep behavior in uranium nitride (UN) has traditionally been described using the Hayes formulation; however, its fidelity degrades outside narrow stress and temperature bounds. A refined creep model is developed that captures deformation behavior across an extended stress-temperature domain. Newly conducted creep experiments, combined with literature data, facilitated the development of the formulation, which incorporates intrinsic pellet parameters—grain size, impurity content, and theoretical density—and provides an accurate representation of UN’s creep behavior. The model shows good agreement with both new experimental data and values reported in the literature. The proposed expression offers a robust, physically grounded predictive tool for UN performance, suitable for direct implementation in fuel performance and reactor simulation codes.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"276 ","pages":"Article 117187"},"PeriodicalIF":5.6,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146045221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
TiVZrNbHf bcc high entropy alloy shows promising hydrogen storage capacity, but unfavourable thermodynamics of the hydride phases i.e., too stable hydrides requiring high temperatures for recovering the stored hydrogen. Mo addition in this composition ((TiVZrNbHf)100-xMoxx = 5, 10 and 16.666) preserves the bcc lattice, decreases the lattice parameter and improves the hydrogen absorption kinetics at room temperature. Moreover, it effectively destabilizes both the bct intermediate and full fcc hydride phases without significant affecting the maximum storage capacity (∼ 2.1 wt. %). The temperatures of successive phase transitions (fcc → bct → bcc) during deuterium desorption strongly reduce with increasing Mo content, as demonstrated by in situ neutron powder diffraction. Several entangled factors can be invoked to explain this thermal destabilization along with electronic structure, steric and electronegativity effects. Therefore, Mo can be proposed as one of the most effective boosting elements to be added in HEAs for hydrogen storage.
TiVZrNbHf bcc高熵合金表现出良好的储氢能力，但氢化物相热力学不利，即氢化物太稳定，需要高温才能回收储存的氢。在该组合物（(TiVZrNbHf)100-xMox x = 5,10和16.666）中添加Mo保留了bcc晶格，降低了晶格参数，改善了室温下的吸氢动力学。此外，它有效地破坏了bct中间和全fcc氢化物相的稳定，而不会显著影响最大存储容量（~ 2.1 wt. %）。原位中子粉末衍射结果表明，随着Mo含量的增加，氘脱附过程中连续相变（fcc→bct→bcc）的温度明显降低。可以用几个纠缠的因素来解释这种热不稳定性以及电子结构、空间和电负性效应。因此，Mo可以作为HEAs储氢中最有效的助推元素之一。
{"title":"Effective destabilization of both mono- and dihydride phases in TiVZrNbHf by Mo addition","authors":"Andrei Agafonov , Faye Greaves , Loïc Perrière , Vivian Nassif , Claudia Zlotea","doi":"10.1016/j.scriptamat.2025.117161","DOIUrl":"10.1016/j.scriptamat.2025.117161","url":null,"abstract":"<div><div>TiVZrNbHf <em>bcc</em> high entropy alloy shows promising hydrogen storage capacity, but unfavourable thermodynamics of the hydride phases <em>i.e.,</em> too stable hydrides requiring high temperatures for recovering the stored hydrogen. Mo addition in this composition ((TiVZrNbHf)<sub>100-<em>x</em></sub>Mo<sub><em>x</em></sub> <em>x</em> = 5, 10 and 16.666) preserves the <em>bcc</em> lattice, decreases the lattice parameter and improves the hydrogen absorption kinetics at room temperature. Moreover, it effectively destabilizes both the <em>bct</em> intermediate and full <em>fcc</em> hydride phases without significant affecting the maximum storage capacity (∼ 2.1 wt. %). The temperatures of successive phase transitions (<em>fcc</em> → <em>bct</em> → <em>bcc</em>) during deuterium desorption strongly reduce with increasing Mo content, as demonstrated by <em>in situ</em> neutron powder diffraction. Several entangled factors can be invoked to explain this thermal destabilization along with electronic structure, steric and electronegativity effects. Therefore, Mo can be proposed as one of the most effective boosting elements to be added in HEAs for hydrogen storage.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"275 ","pages":"Article 117161"},"PeriodicalIF":5.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-04-01Epub Date: 2026-01-23DOI: 10.1016/j.scriptamat.2026.117184
Kil-dong Sung , Michal Gulka , Jaromír Kopeček , Vincent Mortet
The influence of pulsed nitrogen gas flow on microstructure and nitrogen-vacancy (NV) center formation was systematically investigated in polycrystalline diamond layers synthesized by microwave plasma chemical vapor deposition. Compared with static flow, gas pulsing enabled precise control of nitrogen-related radicals and induced a transition from microcrystalline to nanocrystalline diamond, accompanied by variations in residual stress and NV emission. Under optimized nitrogen flow, a bimodal structure emerged, comprising (001)-oriented, flake-like microcrystalline grains embedded in nanocrystalline diamond. Confocal optical analysis revealed that negatively charged NV (NV−) centers were preferentially localized within highly crystalline grains, whereas neutral NV (NV0) centers predominated at grain boundaries, forming spatially separated NV−-rich clusters. Relaxometry demonstrated that the longitudinal relaxation times of flake-like grains were comparable to those of high-quality single-crystal diamond. These findings demonstrate that pulsed nitrogen modulation provides an effective strategy for tailoring diamond microstructure and optimizing NV center formation, offering significant potential for quantum applications.
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