This study harnesses the versatile adaptability of silicon nanowires (Si NWs) to create kink structures by tuning growth pressures and subsequently forming a nickel silicide within the Si NWs via nickel (Ni) atom evaporation and annealing. The transmission electron microscopic (TEM) examination substantiates the presence of Si(111) on both flanks of the Si NWs, showcasing robust structural stability. Intriguingly, the annealing process prompts a transition from Si(111) to NiSi2(111) crystalline orientations, marking a pivotal structural transformation. Our investigation uncovers an interplay between NW morphologies and their ferromagnetic properties. Specifically, single-kinked nanowires exhibit enhanced ferromagnetism, whereas an increase in the number of kinks conversely diminishes their ferromagnetism. A remarkable revelation emerges when we consider the proportion of kinked nanowires within the overall sample. This variable proportion yields disparate ferromagnetic responses. Remarkably, this phenomenon demonstrates that even a simple kink structure holds the key to pioneering the manipulation of ferromagnetic properties within ferromagnetic materials.
{"title":"Tunable ferromagnetism of nickel silicide in kinked silicon nanowires","authors":"Chia-Yi Wu , Cheng-You Shih , Chang-Hsun Huang , Chun-Liang Lin , Yi-Chia Chou","doi":"10.1016/j.scriptamat.2025.117071","DOIUrl":"10.1016/j.scriptamat.2025.117071","url":null,"abstract":"<div><div>This study harnesses the versatile adaptability of silicon nanowires (Si NWs) to create kink structures by tuning growth pressures and subsequently forming a nickel silicide within the Si NWs via nickel (Ni) atom evaporation and annealing. The transmission electron microscopic (TEM) examination substantiates the presence of Si(111) on both flanks of the Si NWs, showcasing robust structural stability. Intriguingly, the annealing process prompts a transition from Si(111) to NiSi<sub>2</sub>(111) crystalline orientations, marking a pivotal structural transformation. Our investigation uncovers an interplay between NW morphologies and their ferromagnetic properties. Specifically, single-kinked nanowires exhibit enhanced ferromagnetism, whereas an increase in the number of kinks conversely diminishes their ferromagnetism. A remarkable revelation emerges when we consider the proportion of kinked nanowires within the overall sample. This variable proportion yields disparate ferromagnetic responses. Remarkably, this phenomenon demonstrates that even a simple kink structure holds the key to pioneering the manipulation of ferromagnetic properties within ferromagnetic materials.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"272 ","pages":"Article 117071"},"PeriodicalIF":5.6,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474569","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 : 2025-10-31DOI: 10.1016/j.scriptamat.2025.117079
Shuainan Xu , Song Fu , Xiaolian Liu , Yulin Ma , Rui Shen , Xuefeng Zhang
Continuous non-ferromagnetic grain boundary phases (GBPs) have been shown to greatly enhance coercivity (∼8 kOe) in Ga-doped Nd-Fe-B magnets after post-sintering annealing (PSA), whereas similar GBP continuity in undoped magnets yields only minor gains (1–3 kOe). In this work, the effect differences between the amounts of Nd-rich phases and their distribution on magnetic properties were directly investigated by adding Nd2O3 oxide. After PSA, the coercivity of magnets steadily increases and then levels off, although it initially decreases and stabilizes with increasing Nd₂O₃ content before annealing. Especially, the addition of Nd2O3 above 1.0 wt.% leads to an enhancement in coercivity by 7.0–8.7 kOe after PSA. The fcc-NdOx GBPs have formed and aggregated at the triple junction areas by the dissociation of hcp-Nd2O3 and Nd-rich phases in sintered magnets. The results directly reveal that the continuous distribution of GBPs plays a more crucial role in coercivity enhancement than its amounts.
{"title":"Microstructural insights into the huge coercivity enhancement after post sinter annealing with the evolution of added Nd2O3 oxide in sintered Nd-Fe-B magnets","authors":"Shuainan Xu , Song Fu , Xiaolian Liu , Yulin Ma , Rui Shen , Xuefeng Zhang","doi":"10.1016/j.scriptamat.2025.117079","DOIUrl":"10.1016/j.scriptamat.2025.117079","url":null,"abstract":"<div><div>Continuous non-ferromagnetic grain boundary phases (GBPs) have been shown to greatly enhance coercivity (∼8 kOe) in Ga-doped Nd-Fe-B magnets after post-sintering annealing (PSA), whereas similar GBP continuity in undoped magnets yields only minor gains (1–3 kOe). In this work, the effect differences between the amounts of Nd-rich phases and their distribution on magnetic properties were directly investigated by adding Nd<sub>2</sub>O<sub>3</sub> oxide. After PSA, the coercivity of magnets steadily increases and then levels off, although it initially decreases and stabilizes with increasing Nd₂O₃ content before annealing. Especially, the addition of Nd<sub>2</sub>O<sub>3</sub> above 1.0 wt.% leads to an enhancement in coercivity by 7.0–8.7 kOe after PSA. The <em>fcc</em>-NdO<sub>x</sub> GBPs have formed and aggregated at the triple junction areas by the dissociation of <em>hcp</em>-Nd<sub>2</sub>O<sub>3</sub> and Nd-rich phases in sintered magnets. The results directly reveal that the continuous distribution of GBPs plays a more crucial role in coercivity enhancement than its amounts.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"272 ","pages":"Article 117079"},"PeriodicalIF":5.6,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425279","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 : 2025-10-31DOI: 10.1016/j.scriptamat.2025.117067
X.Y. Xu , Zhen-Ming Hua , Chen Hu , Hui-Yuan Wang , M.X. Huang
The promising low-alloyed Mg-Zn-Ca-based alloys often exhibit a discontinuous yielding after aging, associated with Lüders bands that can affect sheet-forming quality; however, the underlying mechanism remains unclear. Here, the aging-induced discontinuous yielding is investigated in a low-alloyed Mg-Zn-Ca-Mn-Y alloy. Microstructural characterizations reveal that aging produces coarse η′ precipitates at grain boundaries and fine η′ precipitates within grain interiors, separated by distinct precipitate-free zones (PFZs). The absence of strengthening precipitates in PFZs leads to localized softening, facilitating preferential activation of 〈a〉 dislocations. Compared with the homogeneous deformation in the solution-treated sample, strain localization at PFZs induces heterogeneous plasticity and discontinuous yielding in the peak-aged sample. By varying aging time to modify the PFZ width, the yield point elongation changes correspondingly, further confirming the critical role of PFZs in governing the plasticity in the Mg alloy. These findings offer guidance for tailoring precipitation microstructures to mitigate Lüders banding and enhance sheet-forming performance.
有前途的低合金mg - zn - ca基合金在时效后往往表现出不连续的屈服，并伴有影响板料成形质量的lders带；然而，其潜在机制尚不清楚。本文研究了低合金Mg-Zn-Ca-Mn-Y合金时效引起的不连续屈服。显微组织表征表明时效在晶界处产生粗η′相，在晶内产生细η′相，并由明显的无析出带（PFZs）隔开。pfz中强化相的缺失导致了局部软化，有利于< a >位错的优先激活。与固溶处理试样的均匀变形相比，pfz处的应变局部化导致峰时效试样的非均匀塑性和不连续屈服。通过改变时效时间来改变PFZ宽度，相应改变屈服点伸长率，进一步证实了PFZ在镁合金塑性控制中的关键作用。这些发现为定制沉淀微结构提供了指导，以减轻 ders带状带并提高板料成形性能。
{"title":"Impact of aging-induced precipitate-free zones on yielding mechanisms in a low-alloyed Mg-Zn-Ca-Mn-Y alloy","authors":"X.Y. Xu , Zhen-Ming Hua , Chen Hu , Hui-Yuan Wang , M.X. Huang","doi":"10.1016/j.scriptamat.2025.117067","DOIUrl":"10.1016/j.scriptamat.2025.117067","url":null,"abstract":"<div><div>The promising low-alloyed Mg-Zn-Ca-based alloys often exhibit a discontinuous yielding after aging, associated with Lüders bands that can affect sheet-forming quality; however, the underlying mechanism remains unclear. Here, the aging-induced discontinuous yielding is investigated in a low-alloyed Mg-Zn-Ca-Mn-Y alloy. Microstructural characterizations reveal that aging produces coarse η′ precipitates at grain boundaries and fine η′ precipitates within grain interiors, separated by distinct precipitate-free zones (PFZs). The absence of strengthening precipitates in PFZs leads to localized softening, facilitating preferential activation of 〈<strong><em>a</em></strong>〉 dislocations. Compared with the homogeneous deformation in the solution-treated sample, strain localization at PFZs induces heterogeneous plasticity and discontinuous yielding in the peak-aged sample. By varying aging time to modify the PFZ width, the yield point elongation changes correspondingly, further confirming the critical role of PFZs in governing the plasticity in the Mg alloy. These findings offer guidance for tailoring precipitation microstructures to mitigate Lüders banding and enhance sheet-forming performance.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"272 ","pages":"Article 117067"},"PeriodicalIF":5.6,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425282","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 : 2025-10-30DOI: 10.1016/j.scriptamat.2025.117068
A. Zafari , K. Xia
A new strategy for future alloys by hybridising microstructures of existing alloys using selective laser melting was introduced. In particular, two existing Ti alloys were hybridised, leading to a new Ti, referred to as Hybrid Ti Alloy (HYTA). An excellent combination of high strength, work hardening and ductility was achieved, superior to conventional Ti. Further, individual properties of HYTA were manipulated via simple heat treatments, revealing great versatility. This novel approach can be applied to a vast variety of metals beyond Ti and contributes significantly to the coming era of microstructure-by-design.
{"title":"Superior titanium from hybridised microstructures––a new strategy for future alloys","authors":"A. Zafari , K. Xia","doi":"10.1016/j.scriptamat.2025.117068","DOIUrl":"10.1016/j.scriptamat.2025.117068","url":null,"abstract":"<div><div>A new strategy for future alloys by hybridising microstructures of existing alloys using selective laser melting was introduced. In particular, two existing Ti alloys were hybridised, leading to a new Ti, referred to as Hybrid Ti Alloy (HYTA). An excellent combination of high strength, work hardening and ductility was achieved, superior to conventional Ti. Further, individual properties of HYTA were manipulated via simple heat treatments, revealing great versatility. This novel approach can be applied to a vast variety of metals beyond Ti and contributes significantly to the coming era of microstructure-by-design.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"272 ","pages":"Article 117068"},"PeriodicalIF":5.6,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425281","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 : 2025-10-30DOI: 10.1016/j.scriptamat.2025.117072
Yifei Liang , Quan Li , Haoyu Wang , Qian Qiu , Huanhuan Li , Ying Zheng , Chunlin Song , Xiucai Wang , Yan Yan , Haibo Zhang , Gang Liu , Sheng-Guo Lu
Electrocaloric refrigeration technology demonstrates tremendous potential in microelectronic device cooling due to its merits, including high energy efficiency, cost-effectiveness, and ease of miniaturization. Nevertheless, its development remains constrained by the limitations of existing materials, including a narrow operating temperature span (Tₛₚₐₙ), low adiabatic temperature change (ΔT), and an operating Tₛₚₐₙ that is often too high for practical applications. To address these challenges, Ba0.94-xCa0.06SrxSn0.09Ti0.91O3 ceramics were fabricated via solid-state reaction. In this work, the dispersion of multiphase transitions was enhanced through ion doping, establishing a continuous ferro-ferroelectric and ferro-paraelectric (FF&FP) phase transition zone and simultaneously constructing cooperative multi-domain coexistence. Finally, the material achieves a ΔTmax (maximum adiabatic temperature change value) of 1.47 K (measured by the direct method) and a ΔTmax of 1.18 K (measured by the indirect method) with an ultra-wide Tₛₚₐₙ of 71 °C (ΔT ≥ 90 % of ΔTₘₐₓ) near room temperature (RT), demonstrating a high-performance eco-friendly electrocaloric solution for solid-state refrigeration.
{"title":"The broad electrocaloric working temperature range in Ba0.94-xCa0.06SrxSn0.09Ti0.91O3 lead-free ceramics achieved by multistage phase transitions modification and domain engineering","authors":"Yifei Liang , Quan Li , Haoyu Wang , Qian Qiu , Huanhuan Li , Ying Zheng , Chunlin Song , Xiucai Wang , Yan Yan , Haibo Zhang , Gang Liu , Sheng-Guo Lu","doi":"10.1016/j.scriptamat.2025.117072","DOIUrl":"10.1016/j.scriptamat.2025.117072","url":null,"abstract":"<div><div>Electrocaloric refrigeration technology demonstrates tremendous potential in microelectronic device cooling due to its merits, including high energy efficiency, cost-effectiveness, and ease of miniaturization. Nevertheless, its development remains constrained by the limitations of existing materials, including a narrow operating temperature span (<em>Tₛₚₐₙ</em>), low adiabatic temperature change (<em>ΔT</em>), and an operating <em>Tₛₚₐₙ</em> that is often too high for practical applications. To address these challenges, Ba<sub>0.94-</sub><em><sub>x</sub></em>Ca<sub>0.06</sub>Sr<em><sub>x</sub></em>Sn<sub>0.09</sub>Ti<sub>0.91</sub>O<sub>3</sub> ceramics were fabricated via solid-state reaction. In this work, the dispersion of multiphase transitions was enhanced through ion doping, establishing a continuous ferro-ferroelectric and ferro-paraelectric (FF&FP) phase transition zone and simultaneously constructing cooperative multi-domain coexistence. Finally, the material achieves a <em>ΔT<sub>max</sub></em> (maximum adiabatic temperature change value) of 1.47 K (measured by the direct method) and a <em>ΔT<sub>max</sub></em> of 1.18 K (measured by the indirect method) with an ultra-wide <em>Tₛₚₐₙ</em> of 71 °C (<em>ΔT</em> ≥ 90 % of <em>ΔTₘₐₓ</em>) near room temperature (RT), demonstrating a high-performance eco-friendly electrocaloric solution for solid-state refrigeration.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"272 ","pages":"Article 117072"},"PeriodicalIF":5.6,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425280","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 : 2025-10-30DOI: 10.1016/j.scriptamat.2025.117070
Ming Li , Kun Jiang , Yu Duan , Ping Qu , Bowen Zhang , Xiaoyang Fang , Binglun Yin , Yeqiang Bu , Hongtao Wang , Wei Yang
Room-temperature compressive creep deformation threatens the long-term reliability of deep-sea pressure hulls. Its distinct stress states and thermal activation energies make conventional high-temperature or tensile creep mechanisms inadequate for this scenario. This study investigates the compressive creep mechanism of Ti80 alloy, focusing on microstructural evolution and dislocation behavior under prolonged near-yield stress conditions. Using multiscale characterization techniques from the micron to atomic scale, including quasi in-situ and in-situ methods, we demonstrate that premature dislocation nucleation at interfaces—the primary mechanism for room-temperature compressive creep—is linked to nanoscale γ phases at α/β interfaces, which have lower critical resolved shear stress (CRSS) for dislocation activation and serve as bridges for dislocations transmission. Our findings provide mechanistic insight into room-temperature compressive creep and offer guidance for alloy design and service life prediction of deep-sea pressure hulls.
{"title":"Weak interface mediated room-temperature creep in titanium alloy","authors":"Ming Li , Kun Jiang , Yu Duan , Ping Qu , Bowen Zhang , Xiaoyang Fang , Binglun Yin , Yeqiang Bu , Hongtao Wang , Wei Yang","doi":"10.1016/j.scriptamat.2025.117070","DOIUrl":"10.1016/j.scriptamat.2025.117070","url":null,"abstract":"<div><div>Room-temperature compressive creep deformation threatens the long-term reliability of deep-sea pressure hulls. Its distinct stress states and thermal activation energies make conventional high-temperature or tensile creep mechanisms inadequate for this scenario. This study investigates the compressive creep mechanism of Ti80 alloy, focusing on microstructural evolution and dislocation behavior under prolonged near-yield stress conditions. Using multiscale characterization techniques from the micron to atomic scale, including quasi in-situ and in-situ methods, we demonstrate that premature dislocation nucleation at interfaces—the primary mechanism for room-temperature compressive creep—is linked to nanoscale γ phases at α/β interfaces, which have lower critical resolved shear stress (<em>CRSS</em>) for dislocation activation and serve as bridges for dislocations transmission. Our findings provide mechanistic insight into room-temperature compressive creep and offer guidance for alloy design and service life prediction of deep-sea pressure hulls.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"272 ","pages":"Article 117070"},"PeriodicalIF":5.6,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425204","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 : 2025-10-29DOI: 10.1016/j.scriptamat.2025.117074
Jiaqi Dong , Alexander Demblon , Roberto Orrostieta , Gianna M. Valentino , Ibrahim Karaman , Kelvin Y. Xie
This study investigates the constant force thermal cycling fatigue behavior of Ni50.3Ti29.7Hf20 high-temperature shape memory alloys, focusing on why precipitate-free alloys exhibit poorer structural fatigue life than their precipitate-bearing counterparts. Three samples were examined: as-extruded (AE, precipitate-free), peak-aged (PA), and overaged (OA). The AE sample showed the lowest structural fatigue life, failing after 580 thermal cycles. Microstructural characterization after 580 cycles revealed the highest crack density in the AE sample, attributed to strain incompatibility from its largest actuation strain and abundant dislocations that likely caused stress concentrations via pile-up at austenite grain boundaries. In contrast, the PA and OA samples exhibited lower actuation strains, reducing strain incompatibility. Their precipitates also likely pinned dislocations. Together, these effects limited crack formation and delayed structural failure. These findings underscore the critical interplay among actuation strain, dislocation activity, and cracking in governing the structural fatigue behavior of shape memory alloys.
{"title":"Understanding the poor structural fatigue life in precipitate-free NiTiHf high-temperature shape memory alloy under constant force thermal cycling","authors":"Jiaqi Dong , Alexander Demblon , Roberto Orrostieta , Gianna M. Valentino , Ibrahim Karaman , Kelvin Y. Xie","doi":"10.1016/j.scriptamat.2025.117074","DOIUrl":"10.1016/j.scriptamat.2025.117074","url":null,"abstract":"<div><div>This study investigates the constant force thermal cycling fatigue behavior of Ni<sub>50.3</sub>Ti<sub>29.7</sub>Hf<sub>20</sub> high-temperature shape memory alloys, focusing on why precipitate-free alloys exhibit poorer structural fatigue life than their precipitate-bearing counterparts. Three samples were examined: as-extruded (AE, precipitate-free), peak-aged (PA), and overaged (OA). The AE sample showed the lowest structural fatigue life, failing after 580 thermal cycles. Microstructural characterization after 580 cycles revealed the highest crack density in the AE sample, attributed to strain incompatibility from its largest actuation strain and abundant dislocations that likely caused stress concentrations via pile-up at austenite grain boundaries. In contrast, the PA and OA samples exhibited lower actuation strains, reducing strain incompatibility. Their precipitates also likely pinned dislocations. Together, these effects limited crack formation and delayed structural failure. These findings underscore the critical interplay among actuation strain, dislocation activity, and cracking in governing the structural fatigue behavior of shape memory alloys.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"272 ","pages":"Article 117074"},"PeriodicalIF":5.6,"publicationDate":"2025-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425203","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 : 2025-10-29DOI: 10.1016/j.scriptamat.2025.117076
Jihua Geng , Hang Zhang , Yamei Mao , Yongnan Chen , Nan Wang , Qinyang Zhao , Yan Kang , Zhimin Hou , Lixia Zhu
This work investigates the configurational evolution of basal-pyramidal (B-P) dislocation locks in TA18 alloy and their influence on deformation incompatibility. We reveal that complex dislocation reactions lead to significant intergranular deformation heterogeneity, even under conditions of low slip transmission resistance. Specifically, basal 〈a〉 dislocations interact with pyramidal 〈c + a〉 dislocations to form sessile B-P locks, which significantly impede dislocation motion and induce localized stress concentrations. Furthermore, we characterize the metastable nature of pyramidal 〈c + a〉 dislocation within the B-P lock and elucidate its dissociation into basal 〈a〉 and prismatic 〈c〉 dislocations. This dissociation is identified as a thermodynamically driven process of dislocation core reconstruction, ultimately facilitating plastic flow. The physical origin of dislocation dissociation lies in the transformation of high-energy dislocation cores into low-energy configurations on alternative slip planes. These findings provide valuable insights into the multi-scale coupled mechanisms governing plastic deformation in titanium alloys.
本文研究了TA18合金中基底-锥体（B-P）位错锁的构型演变及其对变形不相容的影响。我们发现，即使在低滑移传递阻力的条件下，复杂的位错反应也会导致显著的晶间变形不均匀性。具体而言，基底< a >位错与锥体< c + a >位错相互作用，形成坚固的B-P锁，显著阻碍位错运动并诱导局部应力集中。此外，我们描述了B-P锁内锥体< c + a >位错的亚稳态性质，并阐明了其解离为基底< a >位错和棱柱形< c >位错。这种解离被认为是一个热力学驱动的位错核心重建过程，最终促进了塑性流动。位错解离的物理根源在于高能位错核在交替滑移面上向低能位错核的转变。这些发现为研究钛合金塑性变形的多尺度耦合机制提供了有价值的见解。
{"title":"Effects of basal-pyramidal dislocation lock on intergranular deformation incompatibility in near-α titanium alloy","authors":"Jihua Geng , Hang Zhang , Yamei Mao , Yongnan Chen , Nan Wang , Qinyang Zhao , Yan Kang , Zhimin Hou , Lixia Zhu","doi":"10.1016/j.scriptamat.2025.117076","DOIUrl":"10.1016/j.scriptamat.2025.117076","url":null,"abstract":"<div><div>This work investigates the configurational evolution of basal-pyramidal (B-P) dislocation locks in TA18 alloy and their influence on deformation incompatibility. We reveal that complex dislocation reactions lead to significant intergranular deformation heterogeneity, even under conditions of low slip transmission resistance. Specifically, basal 〈<em>a〉</em> dislocations interact with pyramidal 〈<em>c</em> + <em>a〉</em> dislocations to form sessile B-P locks, which significantly impede dislocation motion and induce localized stress concentrations. Furthermore, we characterize the metastable nature of pyramidal 〈<em>c</em> + <em>a〉</em> dislocation within the B-P lock and elucidate its dissociation into basal 〈<em>a〉</em> and prismatic 〈<em>c〉</em> dislocations. This dissociation is identified as a thermodynamically driven process of dislocation core reconstruction, ultimately facilitating plastic flow. The physical origin of dislocation dissociation lies in the transformation of high-energy dislocation cores into low-energy configurations on alternative slip planes. These findings provide valuable insights into the multi-scale coupled mechanisms governing plastic deformation in titanium alloys.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"272 ","pages":"Article 117076"},"PeriodicalIF":5.6,"publicationDate":"2025-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425202","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 : 2025-10-28DOI: 10.1016/j.scriptamat.2025.117073
Pavel Nikitin , Maxime Guinel de France , Frederic Sansoz
Immiscible Ag-Cu alloys exhibit complex behavior due to varying Cu solid solubilities reported under equilibrium and metastable conditions. In ultrafine-grained alloys, these limits are further complicated by a high fraction of grain boundaries, where solute atoms tend to segregate and, in some cases, form clusters. This study investigates the influence of Cu solute segregation and clustering on solid-solution limits in ultrafine-grained Ag-Cu alloys synthesized by magnetron sputtering with varying Cu content. X-ray diffraction peak shifts reveal a solid-solution concentration plateau for Cu contents from 4.9 to 11.7 at %, in contrast to the peak shifts predicted by density-functional theory for Ag-Cu alloys. Scanning transmission electron microscopy further reveals limited solid solubility and the formation of numerous Cu-rich clusters at grain boundaries. Atomistic simulations demonstrate that such limited solubility does not arise from grain boundary segregation alone, but only when strong solute-solute interactions promote the formation of grain-boundary Cu solute clusters.
{"title":"Solid solutions limited by grain-boundary solute clustering in ultrafine-grained alloys","authors":"Pavel Nikitin , Maxime Guinel de France , Frederic Sansoz","doi":"10.1016/j.scriptamat.2025.117073","DOIUrl":"10.1016/j.scriptamat.2025.117073","url":null,"abstract":"<div><div>Immiscible Ag-Cu alloys exhibit complex behavior due to varying Cu solid solubilities reported under equilibrium and metastable conditions. In ultrafine-grained alloys, these limits are further complicated by a high fraction of grain boundaries, where solute atoms tend to segregate and, in some cases, form clusters. This study investigates the influence of Cu solute segregation and clustering on solid-solution limits in ultrafine-grained Ag-Cu alloys synthesized by magnetron sputtering with varying Cu content. X-ray diffraction peak shifts reveal a solid-solution concentration plateau for Cu contents from 4.9 to 11.7 at %, in contrast to the peak shifts predicted by density-functional theory for Ag-Cu alloys. Scanning transmission electron microscopy further reveals limited solid solubility and the formation of numerous Cu-rich clusters at grain boundaries. Atomistic simulations demonstrate that such limited solubility does not arise from grain boundary segregation alone, but only when strong solute-solute interactions promote the formation of grain-boundary Cu solute clusters.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"272 ","pages":"Article 117073"},"PeriodicalIF":5.6,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425201","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 : 2025-10-27DOI: 10.1016/j.scriptamat.2025.117069
Wenqian Wu , Amit Misra , Jian Wang
In multi-phase microstructures with soft/hard phases, the interaction of glide dislocations with interfaces may result in dislocation transmission into the hard phase promoting plastic co-deformation or reflection back into the soft phase enhancing strain hardening. The competition between athermal energy barriers for dislocation transmission across or reflection from interface is analyzed using atomistic modeling. The model predicts that the critical plastic deformation incompatibility needed for transmission to prevail over reflection can be reduced by local stress build-up in hard phase and stress fields of soft phase glide dislocations accumulated at interfaces. Moreover, higher interfacial shear strength reduces the energy barriers for both slip transmission and reflection. The proposed atomistic modeling approach for evaluating slip transmission and reflection energy barriers and plastic incompatibility is broadly applicable to metallic systems with available interatomic potentials.
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