Acta Materialia最新文献_第9页

Phase transformations induced by thermo hydrogen treatment in Ti-15 at.% Fe and Ti-15 at.% Cr alloys

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-05 DOI: 10.1016/j.actamat.2025.120906

Qian Wang , Hanbo Weng , Tong Zhang , Sensen Huang , Min Qi , Yingjie Ma , Christophe Schuman , Jean-Sébastien Lecomte , Daokui Xu , Jiafeng Lei , Rui Yang

{"title":"Phase transformations induced by thermo hydrogen treatment in Ti-15 at.% Fe and Ti-15 at.% Cr alloys","authors":"Qian Wang , Hanbo Weng , Tong Zhang , Sensen Huang , Min Qi , Yingjie Ma , Christophe Schuman , Jean-Sébastien Lecomte , Daokui Xu , Jiafeng Lei , Rui Yang","doi":"10.1016/j.actamat.2025.120906","DOIUrl":"10.1016/j.actamat.2025.120906","url":null,"abstract":"<div><div>Hydrogen charging at 1000 °C to two β-Ti alloys, Ti-15 at.% Fe and Ti-15 at.% Cr, was found to induce the precipitation of B2 TiFe and C15 TiCr<sub>2</sub>, respectively. For Ti-15 at.% Fe, the β/TiFe orientation relationship (OR) is Cube-Cube type. At 14 at.% H (nominal), an FCC layer containing {111} twins, having identical composition to the β phase and Baker-Nutting OR with TiFe, formed at β/TiFe interface upon water quenching (WQ). At 28 at.% H, WQ produces α′ martensite and athermal ω instead of the FCC layer at the interface. For TiCr<sub>2</sub> precipitates in Ti-15 at.% Cr, at 16 at.% H, there exist two dominant β/TiCr<sub>2</sub> ORs, leading to three types of twin pairs in TiCr<sub>2</sub>. The β/TiCr<sub>2</sub> interface as well as the twin boundaries are decorated by TiCr<sub>2</sub> stacking faults. At 28 at.% H, the ORs evolve to Kurdjumov-Sachs type, and an FCC layer with internal twins was observed at the β/TiCr<sub>2</sub> interface. The diffusionless formation of the FCC layers in the two alloys as well as the occurrence of twinning effectively relieved the large strains at β/TiFe and β/TiCr<sub>2</sub> interface. An analysis based on displacement gradient tensor has been conducted, and the results provide effective means for understanding the twin variant selection and strain relieving mechanism.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120906"},"PeriodicalIF":8.3,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143560851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the grain size dependence of competing deformation mechanisms in a CrCoNi medium entropy alloy

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-05 DOI: 10.1016/j.actamat.2025.120907

Li Zhu , Guangya Li , Weixia Dong , Jianyang Zhang , Yuemin Ma , Haiyan He , Si Lan , Zhenduo Wu , Xiaohu Li , Tao Yang , Xun-Li Wang

{"title":"On the grain size dependence of competing deformation mechanisms in a CrCoNi medium entropy alloy","authors":"Li Zhu , Guangya Li , Weixia Dong , Jianyang Zhang , Yuemin Ma , Haiyan He , Si Lan , Zhenduo Wu , Xiaohu Li , Tao Yang , Xun-Li Wang","doi":"10.1016/j.actamat.2025.120907","DOIUrl":"10.1016/j.actamat.2025.120907","url":null,"abstract":"<div><div>Grain refinement is an effective approach to tailoring the deformation mechanism and thus the mechanical properties of a material. In this study, the deformation behaviors of the CrCoNi medium entropy alloy with different grain sizes were investigated by in-situ neutron diffraction and transmission electron microscopy observations. For the coarse-grained CrCoNi alloy, the initial plastic deformation was driven by dislocation slip, while stacking faults and twinning became activated at a later stage. The critical stress for stacking faults in coarse-grained samples exhibited a weaker grain size sensitivity than that of dislocation slip. As a result, below a grain size threshold, the critical stress needed to trigger the dislocation slip caught up with that of stacking faults. It was shown that for CrCoNi, when the grain size was below ∼1.5 μm, all the three deformation modes, namely, dislocation slip, stacking faults, and twinning, were activated simultaneously, which resulted in a grain-size dependence deviating from the Hall-Petch relationship due to the extra strengthening at yielding. The contributions from dislocations and planar faults to the work hardening were quantified, which revealed a dominant role of dislocations in the hardening behaviors of the CrCoNi alloy. However, the relative magnitude of these contributions changed as the grain size was reduced, with the contribution from planar faults, especially the stacking faults, becoming increasingly significant.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120907"},"PeriodicalIF":8.3,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143560850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of alloying elements on the hydrogen behaviors of FCC Co-free concentrated solid solution alloys

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-04 DOI: 10.1016/j.actamat.2025.120879

Xudong An , Eryang Lu , Qianqian Wang , Xiaoyu Gui , Qigui Yang , Te Zhu , Xingzhong Cao , Peng Zhang , Huiqiu Deng , Wangyu Hu , Tengfei Yang

{"title":"Effects of alloying elements on the hydrogen behaviors of FCC Co-free concentrated solid solution alloys","authors":"Xudong An , Eryang Lu , Qianqian Wang , Xiaoyu Gui , Qigui Yang , Te Zhu , Xingzhong Cao , Peng Zhang , Huiqiu Deng , Wangyu Hu , Tengfei Yang","doi":"10.1016/j.actamat.2025.120879","DOIUrl":"10.1016/j.actamat.2025.120879","url":null,"abstract":"<div><div>This study investigated hydrogen behaviors in two cobalt-free concentrated solid solution alloys (CSAs) Fe<sub>50</sub>Mn<sub>25</sub>Ni<sub>10</sub>Cr<sub>15</sub> and Ni<sub>57.6</sub>Cr<sub>19.2</sub>Fe<sub>19.2</sub>Nb<sub>4</sub> combining experiments and theoretical methods. We aimed to reveal and elucidate the influencing mechanisms of alloying elements on the hydrogen behaviors of CSAs. After deuterium charging, Ni<sub>57.6</sub>Cr<sub>19.2</sub>Fe<sub>19.2</sub>Nb<sub>4</sub> exhibits higher concentration of deuterium and vacancies than Fe<sub>50</sub>Mn<sub>25</sub>Ni<sub>10</sub>Cr<sub>15</sub>. Density function theory calculations reveal that Ni<sub>57.6</sub>Cr<sub>19.2</sub>Fe<sub>19.2</sub>Nb<sub>4</sub> has lower dissolution energies, which is attributed to the opposite effects of Fe and Ni on hydrogen solubility and severe lattice distortion primarily induced by Nb. The Ni<sub>57.6</sub>Cr<sub>19.2</sub>Fe<sub>19.2</sub>Nb<sub>4</sub> alloys have higher hydrogen binding energy and jump barriers, which enhance hydrogen stability. Furthermore, the precipitates enriched with Nb formed during deformation can block the movements of dislocations and hydrogen, which strengthen the materials and retard the formation and propagation of cracks. Our study highlights the important role of the Nb enriched precipitates for the resistances to hydrogen embrittlement, whose formation is induced by the synergetic effects of hydrogen and deformation. The experimental observations are well explained by theoretical modeling and provide valuable insights for developing CSAs with enhanced resistance to hydrogen embrittlement.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120879"},"PeriodicalIF":8.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of magnetism on the interfacial structure, phase stability and thermal decomposition of (Ti,Al)N/CrN multilayers: Ab initio and experimental study

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-04 DOI: 10.1016/j.actamat.2025.120897

Jie Zhang , Chun Hu , Li Chen , Yi Kong , She Q. Wang , Paul H. Mayrhofer

{"title":"Influence of magnetism on the interfacial structure, phase stability and thermal decomposition of (Ti,Al)N/CrN multilayers: Ab initio and experimental study","authors":"Jie Zhang , Chun Hu , Li Chen , Yi Kong , She Q. Wang , Paul H. Mayrhofer","doi":"10.1016/j.actamat.2025.120897","DOIUrl":"10.1016/j.actamat.2025.120897","url":null,"abstract":"<div><div>By virtue of its outstanding structural and thermal stability, the (Ti,Al)N/CrN multilayer has attracted widespread attention over recent decades. However, the temperature-sensitive magnetic arrangement within the CrN layer challenges the research on the intrinsic mechanism of performance enhancement, where a paramagnetic-to-antiferromagnetic transformation occurs below Néel temperature of 280 K. Here, we systematically studied the effect of magnetic ordering on interfacial and phase stability as well as the thermal decomposition behavior of (Ti,Al)N/CrN multilayer combining experimental and theoretical approaches. The synthesized (Ti,Al)N/CrN multilayer exhibits a face-centered cubic structure with well-defined coherent interfaces. <em>Ab initio</em> calculations confirm that the coherent epitaxial growth between (Ti,Al)N and TMN (TM = Ti, Zr, and Cr) depends on the layer-to-layer lattice mismatch and the Al content within the (Ti,Al)N layer. Compared to antiferromagnetic feature, the ferromagnetic one in CrN enhances the coherent interface stability and interface bond strength, but has little influence of the cubic phase stability. Moreover, annealing treatment promotes the interface-directed spinodal decomposition of (Ti,Al)N/CrN due to ferromagnetic configuration, which reduces the activation energy of Al nearby interfaces along the preferred diffusion towards the interior of the (Ti,Al)N layers. Thereby, the (Ti,Al)N layer forms lamellar Al-rich/Ti-rich/Al-rich regions. As temperature increases to 1000 °C, Cr crosses the fcc-AlN-rich lamella towards the inner fcc-TiN-rich lamella of the original (Ti,Al)N layer, which brings about the collapse of the lamellar structure.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120897"},"PeriodicalIF":8.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Metastable AlB2 structured TM-Si-B2±z (TM = Ti, Zr, Hf) solid solutions from first-principles

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-04 DOI: 10.1016/j.actamat.2025.120857

C. Gutschka , L. Zauner , T. Glechner , D. Holec , H. Riedl

{"title":"Metastable AlB2 structured TM-Si-B2±z (TM = Ti, Zr, Hf) solid solutions from first-principles","authors":"C. Gutschka , L. Zauner , T. Glechner , D. Holec , H. Riedl","doi":"10.1016/j.actamat.2025.120857","DOIUrl":"10.1016/j.actamat.2025.120857","url":null,"abstract":"<div><div>AlB<sub>2</sub> structured transition metal diborides are a class of refractory ceramics standing out through their high-temperature stability and exceptional mechanical properties, encouraging research on their bulk and thin film forms. In Physical Vapor Deposition (PVD), scientific interest has focused on growing metastable solid solutions with Si to enhance oxidative properties and fracture characteristics. However, theoretical investigations of such ternary compounds are still rare. Therefore, this study explores the structural, energetical, and mechanical properties of the Ti-Si-B<sub>2</sub>, Zr-Si-B<sub>2</sub>, and Hf-Si-B<sub>2</sub> structures, as well as their vacancy dynamics, with the help of Density Functional Theory (DFT). For all three systems, silicon prefers the boron sublattice and via structural analysis, metastable solubility limits of 24 at. %, 27 at. %, and 25 at. % of Si in Ti(Si,B)<sub>2</sub>, Zr(Si,B)<sub>2</sub>, and Hf(Si,B)<sub>2</sub>, could be established, respectively. An analysis of simulated XRD patterns, Radial Distribution Functions (RDFs), and Crystal Orbital Hamilton Populations (COHPs), attributed an observed destabilization of the AlB<sub>2</sub>-type symmetry to Si clustering. Simulated elastic properties revealed a decrease of the Young’s moduli with increasing silicon contents, reproducing experimental values up to 15 at. % Si. The study discovered a structural instability of ternary, metastable AlB<sub>2</sub>-type compounds concerning metal vacancies.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120857"},"PeriodicalIF":8.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Greatly enhanced electrical resistivity in La3Ta0.5Ga5.3Al0.2O14 high temperature piezoelectric crystal through microscopic defect engineering

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-04 DOI: 10.1016/j.actamat.2025.120867

Dongjie Liu , Linyu Bai , Xiulan Duan , Yanlu Li , Xian Zhao , Shujun Zhang , Fapeng Yu

{"title":"Greatly enhanced electrical resistivity in La3Ta0.5Ga5.3Al0.2O14 high temperature piezoelectric crystal through microscopic defect engineering","authors":"Dongjie Liu , Linyu Bai , Xiulan Duan , Yanlu Li , Xian Zhao , Shujun Zhang , Fapeng Yu","doi":"10.1016/j.actamat.2025.120867","DOIUrl":"10.1016/j.actamat.2025.120867","url":null,"abstract":"<div><div>Enhancing the electrical resistivity of piezoelectric crystals is essential for improving the sensing capability of high temperature piezoelectric sensors, especially at low frequency range. In this work, we investigated the conduction mechanism of the La<sub>3</sub>Ta<sub>0.5</sub>Ga<sub>5.3</sub>Al<sub>0.2</sub>O<sub>14</sub> (LTGA) crystal and elucidated the role of intrinsic defects in electrical resistivity. Our findings indicate that the conductive behaviors are closely related to the point defects, such as oxygen vacancy and Al<sub>Ta</sub> antisite defects, in LTGA crystal. The dominant Al<sub>Ta</sub> antisite defects facilitate carrier migration, and make hole carrier emission easier due to the small lattice distortion among the Al<sub>Ta</sub> antisite defects with different valence states. In contrast, electrons are less likely to be trapped, preventing the formation of electron-hole complex centers, thereby increasing hole concentration and electrical conductivity. Interestingly, the oxygen vacancy concentration can modulate the formation energy of Al<sub>Ta</sub> antisite defects, thus influencing electrical resistivity. A higher concentration of oxygen vacancy results in fewer Al<sub>Ta</sub> antisite defects, thus the higher electrical resistivity. By inhibiting the formation of Al<sub>Ta</sub> antisite defects through crystal growth in a low-oxygen atmosphere, we successfully obtained high quality LTGA crystal with two-order of magnitude increase in electrical resistivity.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120867"},"PeriodicalIF":8.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143539213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Magnetic transparent conductors for spintronic applications

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-03 DOI: 10.1016/j.actamat.2025.120850

Pino D’Amico , Alessandra Catellani , Alice Ruini , Stefano Curtarolo , Marco Fornari , Marco Buongiorno Nardelli , Arrigo Calzolari

{"title":"Magnetic transparent conductors for spintronic applications","authors":"Pino D’Amico , Alessandra Catellani , Alice Ruini , Stefano Curtarolo , Marco Fornari , Marco Buongiorno Nardelli , Arrigo Calzolari","doi":"10.1016/j.actamat.2025.120850","DOIUrl":"10.1016/j.actamat.2025.120850","url":null,"abstract":"<div><div>Transparent Conductors (TCs) exhibit optical transparency and electron conductivity, and are essential for many opto-electronic and photo-voltaic devices. The most common TCs are electron-doped oxides, which are limited in the choice of possible dopants, as transitions metals most often are not suitable, in view of their tendency to form strong bond with oxygen. Non-oxides TCs have the potential of extending the class of materials to the magnetic realm, bypass technological bottlenecks, and bring TCs to the field of spintronics. Here we propose new functional materials that combine transparency and conductivity with magnetic spin polarization that can be used for spintronic applications, such as spin filters. By using high-throughput first-principles techniques, we identified a large number of potential TCs, including non-oxides materials. Our results indicate that proper doping with transition metals introduces a finite magnetization that can provide spin filtering up to 90% in the electrical conductivity, still maintaining a transparency greater than 90%.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120850"},"PeriodicalIF":8.3,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effects of trace Nb dopant on core-shell microstructure and ferroelectric domain switching in BiFeO3-BaTiO3 ceramics

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-03 DOI: 10.1016/j.actamat.2025.120890

Ziqi Yang , Yizhe Li , Juncheng Pan , Bingying Xie , Kexue Li , Katie L. Moore , Annette K. Kleppe , David A. Hall

{"title":"Effects of trace Nb dopant on core-shell microstructure and ferroelectric domain switching in BiFeO3-BaTiO3 ceramics","authors":"Ziqi Yang , Yizhe Li , Juncheng Pan , Bingying Xie , Kexue Li , Katie L. Moore , Annette K. Kleppe , David A. Hall","doi":"10.1016/j.actamat.2025.120890","DOIUrl":"10.1016/j.actamat.2025.120890","url":null,"abstract":"<div><div>BiFeO<sub>3</sub>-BaTiO<sub>3</sub> (BF-BT) solid solutions have great potential as high-temperature piezoelectric transducers and energy storage dielectrics. However, the effects of donor doping in BF-BT on the local chemical heterogeneity and corresponding control of ferroelectric properties are not well investigated. In this study, it is shown that substitution of Nb<sup>5+</sup> for Fe<sup>3+</sup> at a concentration of only 0.1 at% in 0.75BF-0.25BT ceramics can induce pronounced core-shell microstructural features, which are not evident for pure BF-BT ceramics or those doped with 0.1 at% Nb<sup>5+</sup> for Ti<sup>4+</sup>. The spatial distribution of Nb, confirmed by Nano-SIMS with exceptional resolution and sensitivity, reveals the role of Nb as an aliovalent solute that inhibits chemical homogenization, stabilizing the formation of Bi-, Fe-enriched core and Ba-, Ti-enriched shell regions at high temperatures, and reducing inter-diffusion during sintering. Electric field-induced domain switching and lattice strain measurements, obtained by in-situ high-energy synchrotron X-ray diffraction, revealed the effects of elastic constraint between the core and shell regions, which degraded the dielectric, ferroelectric, and piezoelectric properties. In contrast, substitution of 0.1 at% Nb on the Ti<sup>4+</sup> site gave rise to more homogeneous materials and induced a softening effect with enhanced functional properties. This study provides an advanced investigation into the effects of trace amounts of donor dopant in BF-BT ceramics and offers valuable insights into optimizing doping strategy to control their microstructure and functional properties.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120890"},"PeriodicalIF":8.3,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Microstructure evolution in ultra-high purity Fe-Cr alloys under low-PKA proton irradiation

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-03 DOI: 10.1016/j.actamat.2025.120895

Siwei Chen , Yao Li , Yajie Zhao , Zhexian Zhang , Steven J. Zinkle

{"title":"Microstructure evolution in ultra-high purity Fe-Cr alloys under low-PKA proton irradiation","authors":"Siwei Chen , Yao Li , Yajie Zhao , Zhexian Zhang , Steven J. Zinkle","doi":"10.1016/j.actamat.2025.120895","DOIUrl":"10.1016/j.actamat.2025.120895","url":null,"abstract":"<div><div>Fe-Cr based ferritic steels are essential structural materials for nuclear reactor core applications. This study investigates how Cr content and irradiation temperature affect the formation of dislocation loops and the chemical segregation in Fe-Cr binary alloys under proton irradiation with low cascade mixing. Ultra-high purity Fe-Cr alloys containing 8, 10, and 18 wt. % Cr were irradiated by 800 keV protons at a dose rate of 2 × 10<sup>−5</sup> dpa/s up to 2 dpa at 3 μm depth at 250, 350, and 450 °C. Scanning transmission electron microscope (STEM) analysis revealed the formation of “large” and “regular-sized” dislocation loops, which are likely attributed to the direct overlap of displacement cascades and accumulation of interstitials, respectively. The large dislocation loops appear to be more stable at lower irradiation temperatures and with higher Cr concentrations. The size of regular-sized dislocation loops increased, and the number density decreased, with increasing irradiation temperature or decreasing Cr content. The ratio of <em>a</em>〈100〉 to a/2〈111〉 dislocation loops increased at higher irradiation temperatures, while the ratio was independent of Cr content at 250 °C. Clustering and coalescence of <em>a</em>〈100〉 dislocation loops occurred at 350 °C and 450 °C, respectively. STEM coupled with energy dispersive X-ray spectroscopy revealed a transition from heterogeneous Cr segregation around dislocation loops to homogeneous Cr-rich α′ precipitates in the matrix in alloys with Cr content >8 wt.% at 250 °C.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120895"},"PeriodicalIF":8.3,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Exascale granular microstructure reconstruction in 3D volumes of arbitrary geometries with generative learning

IF 8.3 1区材料科学

Acta Materialia Pub Date : 2025-03-03 DOI: 10.1016/j.actamat.2025.120859

Leidong Xu , Zihan Wang , Theron Rodgers , Dehao Liu , Anh Tran , Hongyi Xu

{"title":"Exascale granular microstructure reconstruction in 3D volumes of arbitrary geometries with generative learning","authors":"Leidong Xu , Zihan Wang , Theron Rodgers , Dehao Liu , Anh Tran , Hongyi Xu","doi":"10.1016/j.actamat.2025.120859","DOIUrl":"10.1016/j.actamat.2025.120859","url":null,"abstract":"<div><div>Reconstructing 3D granular microstructures within volumes of arbitrary geometries from limited 2D image data is crucial for predicting the material properties, as well as performances of structural components accounting for material microstructural effects. We present a novel generative learning framework that enables exascale reconstruction of granular microstructures within complex 3D geometric volumes. Building upon existing transfer learning techniques using pre-trained convolutional neural networks (CNN), we introduce several key innovations to overcome the difficulties inherent in arbitrary geometries. Our framework incorporates periodic boundary conditions using circular padding techniques, ensuring continuity and representativeness of the reconstructed microstructures. We also introduce a novel seamless transition reconstruction (STR) method that creates statistically equivalent transition zones to integrate multiple pre-existing 3D microstructure volumes. Based on STR, we propose a cost-effective strategy for reconstructing microstructures within complex geometric volumes, minimizing computational waste. Validation through numerical experiments using kinetic Monte Carlo simulations demonstrates accurate reproduction of grain statistics, including grain size distributions and morphology. A case study involving the reconstruction of a 4-blade propeller microstructure illustrates the method’s capability to efficiently handle complex geometries. The proposed framework significantly reduces computational demands while maintaining high reconstruction quality, paving the way for scalable microstructure reconstruction in materials design and analysis.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"289 ","pages":"Article 120859"},"PeriodicalIF":8.3,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0