Twin Growth Research Articles

Atomistic simulations of dislocation activity in Si nanofibers in Al-Si eutectics

Atomistic simulations were used to elucidate the mechanisms of localized plasticity and fracture in Si nanofibers embedded in Al matrix, with uniaxial tensile straining along the fiber axis. The Si nanofibers within the Al matrix exhibited large non-linear elastic strains followed by localized plasticity with the latter accounting for approximately 5 % permanent length increase in the fibers. On the other hand, simulations with aligned Si nanofibers in vacuum (no Al matrix) exhibited elastic deformation only followed by cleavage fracture. Localized plasticity in Si nanofibers is accomplished by gliding of “zonal” partial dislocations with Burgers vector b=aSi3〈112〉, which leads to synchronous shear of two shuffle-sets. Local stress concentration in Si nanofibers due to non-screw segments of dislocation loops around fibers triggers yielding in the nanofibers through the activation of dislocation sources at or near the interfaces but only below some critical fiber diameter, highlighting the role of nanoscale refinement in activating plasticity in embedded Si nanofibers in Al matrix. In addition, the kinetic barriers associated with the glide of edge/screw zonal dislocation in the perfect crystal and twinned crystal are computed using climbing-image nudge elastic band method. A higher mobility of the zonal dislocation in the twinned crystal suggests that twin boundaries can assist in dislocation glide parallel to the boundary. On the other hand, a nano-crack is nucleated at the interaction position of a glide partial dislocation with an intersecting growth twin boundary suggesting that intersecting twins serve to block glide and provide sites for crack nucleation.

Possible mechanisms of cubic texture generation in heavily rolling face-centered cubic metal due to the annealing twining

Face-centered cubic (FCC) metals were subjected to heavy rolling and two-step recrystallization annealing to form sharp cubic textures. The traditional theory states that the formation of recrystallized cubic-oriented grains originates from rolling cube grains. However, in our study, the Ni8W alloy underwent severe deformation during rolling, forming a typical brass-type rolling texture with almost no cubic-oriented grains. The quasi-3D electron backscatter diffraction results indicated that the newly generated cubic grains were not necessarily adjacent to the rolling cubic grains. Instead of growing from excited rolling cube grains, we found newly oriented recrystallized cubic grains generated from twin growth. Initially, most recrystallized grains undergo grain boundary migration or merging during low-temperature recrystallization annealing. Under such conditions, the initial recrystallized grains maintained the same orientation as the original matrix. However, it is also possible that the initially newly oriented recrystallized grains were generated through twinning. The {221}<122> orientation grains can cause cubic orientation by Σ3 boundaries. This twinning process reveals another pathway for generating initially recrystallized cubic grains in highly deformed FCC alloys. The recrystallized cubic-oriented grains ultimately evolved into cubic textures owing to their growth advantages, as described by the traditional theory. This discovery solves the puzzle of the recrystallization nucleation mechanism for cubic-oriented grains. It can help us better understand the evolution of the recrystallized cubic texture in heavily deformed FCC alloys.

Can growth in dichorionic twins be monitored with individualized growth assessment?

To characterize fetal growth in dichorionic twins using individualized growth assessment (IGA), a method based on individual growth potential estimates. This secondary analysis included 286 fetuses/neonates from 143 dichorionic twin pregnancies that were part of the ESPRiT (Evaluation of Sonographic Predictors of Restricted Growth in Twins) study. The sample was subcategorized according to birth weight into appropriate-for-gestational-age (AGA) (n = 243) and small-for-gestational-age (SGA) (n = 43) cohorts. Serial biometric scans evaluating biparietal diameter, head circumference (HC), abdominal circumference, femur diaphysis length and estimated weight at 2-week intervals were used to evaluate fetal growth, while measurements of birth weight, crown-heel length and HC determined neonatal growth outcome. Six abnormalities (hypoxic ischemic encephalopathy, periventricular leukomalacia, necrotizing enterocolitis, respiratory distress, sepsis and death) constituted the evaluated adverse neonatal outcomes (ANO). IGA was used to: evaluate differences in second-trimester growth velocities between singletons (from a published dataset) and dichorionic twins (138 AGA twins with normal third-trimester growth); describe the degree to which actual third-trimester growth in twins followed expected growth (111 AGA twins, normal fetal growth and neonatal growth outcomes); determine if the fetal growth pathology score 1 (-FGPS1) could detect, quantify and classify twin growth pathology (224 AGA, 42 SGA); and assess the relationship between -FGPS1 and ANO (24 SGA twins with progressive growth restriction confirmed by abnormal neonatal growth outcome). The differences in second-trimester growth velocity between singletons and twins (means and variances) were small and not statistically significant. Percent deviations from the expected third-trimester size trajectories were within the 95% reference ranges derived from singletons at 95.7% (1677/1752) of timepoints studied. Abnormal growth was detected in 37.9% of AGA twins and 85.7% of SGA twins. Growth restriction was more heterogeneous in AGA twins, while in SGA twins progressive growth restriction was the principal type (66.7%). -FGPS1 patterns previously defined in singletons classified 97.5% of pathological twin cases. In our most severe form of growth restriction (progressive), there were only three (12.5%) ANOs related to growth abnormalities, all in cases with -FGPS1 values more negative than -2.0%. Using these criteria, the frequency of ANO was 33%. With respect to growth, dichorionic twins can be considered as two singletons in the same uterus. Normally growing dichorionic twins have the same growth potential as singletons with normal growth outcome. These twins also follow expected third-trimester growth trajectories with the same precision as do singletons. Third-trimester growth pathology can be detected, quantified and classified using -FGPS1 as in singletons. Limited evidence of a relationship between fetal growth abnormalities and adverse neonatal outcome was found. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Evaluating the Impact of Maternal Exposure to Ozone on Twin Fetal Growth in China.

Unlike singletons, twins require attention not only to the birth weight of the fetuses but also to discordance (i.e., the differences between weights) because twin growth discordance is a significant factor contributing to perinatal mortality and morbidity in twin pregnancies. However, the impact of maternal air pollution exposure on twin growth discordance has rarely been investigated. We examined the association of long-term ozone exposure during preconception and pregnancy with the birth weight of twins and twin growth discordance among 35,795 twins from the National Free Preconception Health Examination Project between January 2010 and December 2019. Linear mixed-effect models and random-effect logistic regression models were used to examine the associations of ozone exposure with the birth weight-related outcomes (i.e., birth weight of twins and within-pair birth weight difference) and risk of twin growth discordance, respectively, after adjustment for demographic characteristics and lifestyle. We found that an interquartile range (IQR) increase (15 μg/m3) in ozone exposure during the entire pregnancy was associated with a reduction (-28.96g, 95% confidence interval [CI]: -46.37, -11.56) in the total birth weight of twins, and ozone had a more pronounced impact on the birth weight of the smaller fetuses (-18.28 g, 95% CI: -27.22, -9.34) compared to the larger fetuses (-9.88 g, 95% CI: -18.84, -0.92) in twin pregnancies. An IQR increase in ozone exposure during the entire pregnancy was associated with a significant increase (8.41 g, 95% CI: 4.13, 12.69) in the within-pair birth weight difference; the odds ratio (OR) of twin growth discordance related to ozone exposure increased by 9% (OR = 1.09, 95% CI: 1.01, 1.18). However, no consistently significant associations were observed for ozone exposure during prepregnancy. Male-male twin pairs and those who were born prematurely appeared to be more susceptible to ozone exposure than their counterparts. Long-term ozone exposure during pregnancy was associated with twin growth discordance, and our findings provide reference data for future studies.

Delving into the Digital Twin Developments and Applications in the Construction Industry: A PRISMA Approach

Construction 4.0 is witnessing exponential growth in digital twin (DT) technology developments and applications, revolutionizing the adoption of building information modelling (BIM) and other emerging technologies used throughout the built environment lifecycle. BIM provides technologies, procedures, and data schemas representing building components and systems. At the same time, the DT enhances this with real-time data for integrating cyber-physical systems, enabling live asset monitoring and better decision making. Despite being in the early stages of development, DT applications have rapidly progressed in the AEC sector, resulting in a diverse literature landscape due to the various technologies and parameters involved in fully developing the DT technology. The intricate complexities inherent in digital twin advancements have confused professionals and researchers. This confusion arises from the nuanced distinctions between the two technologies, i.e., BIM and DT, causing a convergence that hinders realizing their potential. To address this confusion and lead to a swift development of DT technology, this study provides a holistic review of the existing research focusing on the critical components responsible for developing the applications of DT technology in the construction industry. It highlights five crucial elements: technologies, maturity levels, data layers, enablers, and functionalities. Additionally, it identifies research gaps and proposes future avenues for streamlined DT developments and applications in the AEC sector. Future researchers and practitioners can target data integrity, integration and transmission, bi-directional interoperability, non-technical factors, and data security to achieve mature digital twin applications for AEC practices. This study highlights the growing significance of DTs in construction and provides a foundation for further advancements in this field to harness its potential to transform built environment practices. It also pinpoints the latest developments in AI, namely the large language model (LLM) and retrieval-augmented generation (RAG)’s implications for DT education, policies, and the construction industry’s practices.

Forest digital twin: A new tool for forest management practices based on Spatio-Temporal Data, 3D simulation Engine, and intelligent interactive environment

Existing forest digitization studies focus on one-way forest management practice visualization simulation, lacking decision-making feedback and virtual-real interaction synchronization. This paper presents the vision of the forest digital twin paradigm. We construct a forest digital twin to explore a new digital carrier of forest resources using remote sensing data, forest inventory data, the Cesium Digital Earth Engine, forest planning theory and parametric 3D modeling technology. The two-way interaction and thinning experiments showed that the forest digital twin could provide a novel pattern for in-depth analysis of forest spatial structure, individual tree dynamic growth and human-digital twin interaction effects. The successful recognition rate in matching the forest structure seen on real forest structure images with the forest digital scene was 91.3%, indicating that the forest digital twin can characterize the real forest structure significantly. The prediction accuracy of the multi-grade growth model integrating the Bayesian method for DBH, H was more than 90.4%. In addition, ASS-FDT interaction is superior to the assessors (ASS) and forest digital twin (FDT) for stand spatial structure overall optimization. The multi-dimensional stand spatial structure index (F-index) increased by 22.82%. The constructed forest digital twin model shows superior performance in optimizing the stand growth model and enhancing the overall stand spatial structure under the decision-making feedback and real-time interaction strategies. The automatic operation pattern provides a user-friendly forest management practice solution.

Amniotic fluid metabolic fingerprinting contributes to shaping the unfavourable intrauterine environment in monochorionic diamniotic twins

Amniotic fluid (AF) is the primary intrauterine environment for fetal growth throughout gestation. Selective fetal growth restriction (sFGR) is an adverse complication characterized by unequal growth in twins with nearly identical genetic makeup. However, the influence of AF-mediated intrauterine environment on the development and progression of sFGR remains unexplored. High-throughput targeted metabolomics analysis (G350) was performed on AF samples collected from sFGR (n=18) and MCDA twins with birth weight concordance (MCDA-C, n=20) cases. Weighted correlation network analysis (WGCNA) was used to identify clinical features that may influence the metabolite composition in AF. Subsequently, partial least-squares discriminant analysis (PLS-DA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to compare the different types of sFGR and MCDA-C twins. Receiver operating characteristic (ROC) and multivariate ROC curves were utilized to explore potential AF markers in twins with sFGR. In our study, 182 metabolites were quantified in 76 AF samples. WGCNA indicated that the metabolite composition in late AF may not be influenced by gestational age. PLSDA demonstrated distinct variations between the metabolite profiles of AF in the sFGR and MCDA-C twins, with a significant emphasis on amino acids as the primary differential metabolite. The dissimilarities observed in sFGR twins were predominantly attributed to lipid metabolism-related metabolites. In particular, the KEGG enrichment metabolic pathway analysis revealed significant associations of both types of sFGR twins with central carbon metabolism in cancer. The multivariate ROC curves indicated that the combination of carnosine, sarcosine, l-alanine, beta-alanine, and alpha-n-phenylacetylglutamine significantly improved the AUC to 0.928. Notably, the ROC curves highlighted creatine (AUC:0.934) may be a potential biomarker for severe sFGR. The data presented in this study offer a comprehensive metabolic map of the AF in cases of sFGR, shedding light on potential biomarkers associated with fetal growth and development in MCDA twins.

Strain Rate Dependence of Twinning Behavior in AZ31 Mg Alloys

This study investigates the impact of strain rate on the twinning process (i.e., twin nucleation, twin propagation, and twin growth) and associated mechanical behavior during compression along the normal direction (ND) and transverse direction (TD) of a rolled AZ31 Mg plate at a range of strain rates from 0.00005 s−1 to 2500 s−1. The findings reveal that the yield strength is insensitive to strain rates below 0.05 s−1 during both ND and TD compression tests, while at higher strain rates of 2500 s−1, the yield strength increases under both loading conditions. Interestingly, the TD-compressed sample exhibits a larger yield plateau at a strain rate of 2500 s−1, attributed to an increased activation of {101¯2} twins. Further examination of the microstructure reveals that the twinning process is highly dependent on the strain rate. As the strain rate increases, twin nucleation is promoted, leading to a higher twin boundary density. In contrast, at lower strain rates, twin nucleation is restrained, and the external strain is mainly accommodated by twin growth, which results in higher area fractions of twinned regions.

A conditional standard for the customized fetal growth trajectory in twin pregnancy

BackgroundThe difference between the birthweights of twins and singletons grows with advancing gestation. Although many fetal weight standards based on ultrasound have been created for tracking fetal growth in twin pregnancies, their applicability to other groups is limited by the fact that they are population-specific. ObjectivesTo generate conditional centiles of growth assessment in twin fetuses and compare them with other population-based growth standards for singleton and twin fetuses. Study DesignA retrospective longitudinal study of the ultrasound-based estimated fetal weight (EFW) dataset of normal twin fetuses delivered after 34 weeks of gestation was conducted. Linear mixed effects models, which adjusted for maternal characteristics, fetal gender, and chorionicity, were used to construct the relationship between EFW and gestational age. The EFW reference values were calculated using conditional centile based on the EFW at an earlier gestational age. To compare our results with previous studies, fetal growth curves were generated using a formula we created which included maternal characteristics and the EFW at 24 weeks of gestation in these studies. In a subgroup analysis of our low-risk twin babies born at full term, we calculated the number of fetuses that were reclassified as being in the bottom 10th percentile using each of the previous population-based standard. Results2644 ultrasounds with a median of 4 scans per fetus from 572 twin pregnancies were included in this analysis. Thirty six percent of the fetuses were monochorionic. Maternal age, body mass index, and the interaction between fetal gender and chorionicity were significantly associated with EFW. The predicted growth curves matched the growth standard for twins. In our low-risk group, when the singleton standard was used, the incidence of EFW 10th percentile was above 20% from gestational week 24–38, and this incidence varied when reclassified using other population-based twin standards. ConclusionsThis conditional growth chart was specifically designed to assess fetal growth in twins, but it is generalizable to other populations.

An insight into mechanical response and twinning behavior of bimodal textured AZ31 magnesium alloy under quasi-static and high strain rate compression

In this work, the dynamic, quasi-static response and twinning behavior of bimodal textured Mg–3Al–1Zn alloy is comparatively investigated at room temperature. The relationship between yield stress and bimodal texture is quantified and characterized as an increase of the yield stress with the increasing of the percentage of <0002>⊥ED (extrusion direction) component; the ultimate strength under high strain rate (103 s−1) was quite higher than that under quasi-static condition (10−3 s−1); but, the yield stress was just the reverse. The competition between twin nucleation and growth is significantly affected by a coupled effect of strain rate and texture. Twin nucleation shows positive strain rate sensitivity and is largely enhanced by dynamic deformation. However, the twin growth tendency is bimodal texture and strain rate dependent: it is favorable under quasi-static condition for samples with more soft orientations, while for samples with more hard orientations, dynamic deformation promotes twin growth. It is also found that a higher strain rate can stimulate the activation of more twin variant types in bimodal textured magnesium alloys.

Microstructural mechanisms imparting high strength-ductility synergy in heterogeneous structured as-cast AlCoCrFeNi2.1 eutectic high-entropy alloy

The dual-phase AlCoCrFeNi2.1 eutectic high-entropy alloy (EHEA) presents a promising solution to the strength-ductility trade-off dilemma, making it a highly desirable option for structural materials with vast potential applications. However, the relationship between the mechanical properties and the unique as-cast heterostructures needs to be further revealed. Here, we conducted in-situ tensile experiments of the as-cast EHEA to unveil the mesoscopic/microscopic microstructural mechanisms of strength-ductility synergy via investigating the dynamic real-time plastic deformation behaviors and crystallographic information evolution, as well as characterizing the deformed microstructures via transmission electron microscopy. The results indicate that the sequential dominant heterogeneous deformation induced hardening resulting from the incompatible plastic deformation between different types of heterogeneous microstructures is the primary source of its remarkable strength-ductility synergy. Moreover, the unique elongated lamellar microstructures of the as-cast EHEA offer numerous phase boundaries, and the growth twins in the face-centered cubic (FCC) phase generate abundant twin boundaries, all of which contribute to boundary strengthening and further enhance the strength and ductility of the as-cast EHEA. Furthermore, abundant cross-slip and dislocation substructures in the FCC phase provide strain hardening for as-cast EHEA, while body-centered cubic phase contributes to the high strength through precipitation hardening. Consequently, the heterostructure induced multiple strengthening mechanisms are responsible for the high strength-ductility synergy in the as-cast EHEA. The present work provides a new perspective to explain the strength-ductility synergy of similar heterogeneous structured alloys.

Carbides in AZ91 and their role in the grain refinement of magnesium

Carbon inoculation is a well-known method to grain refine Mg-Al-based alloys, but the underlying mechanisms remain unclear. Here we study carbides and their relationship with the surrounding magnesium in inoculated Mg-9Al-0.7Zn-0.2Mn (wt.%, AZ91) by combining controlled solidification experiments with analytical electron microscopy. Up to three carbides formed depending on the solidification conditions: T1-Al2MgC2, T2-Al2MgC2 and Al4C3. All carbides grew with their basal planes as the largest facet and the trigonal carbides, T2-Al2MgC2 and Al4C3, often contained basal planar growth faults and growth twins. In many cases there was evidence of eutectic-like Al4C3 growing off T2-Al2MgC2, indicating that Al4C3 formed later in the solidification sequence after α-Mg had nucleated, consistent with recent phase diagram calculations. A basal-to-basal OR was measured between α-Mg and T2-Al2MgC2 for approximately 10% of particles, indicating that T2-Al2MgC2 is the heterogeneous nucleant for α-Mg. Particles with the OR had diverse locations including near grain boundaries and near the centre of grains, suggesting that the OR can form by pushing and engulfment as well as by heterogeneous nucleation.

Association between placental oxygen transport and fetal brain cortical development: a study in monochorionic diamniotic twins.

Normal cortical growth and the resulting folding patterns are crucial for normal brain function. Although cortical development is largely influenced by genetic factors, environmental factors in fetal life can modify the gene expression associated with brain development. As the placenta plays a vital role in shaping the fetal environment, affecting fetal growth through the exchange of oxygen and nutrients, placental oxygen transport might be one of the environmental factors that also affect early human cortical growth. In this study, we aimed to assess the placental oxygen transport during maternal hyperoxia and its impact on fetal brain development using MRI in identical twins to control for genetic and maternal factors. We enrolled 9 pregnant subjects with monochorionic diamniotic twins (30.03 ± 2.39 gestational weeks [mean ± SD]). We observed that the fetuses with slower placental oxygen delivery had reduced volumetric and surface growth of the cerebral cortex. Moreover, when the difference between placenta oxygen delivery increased between the twin pairs, sulcal folding patterns were more divergent. Thus, there is a significant relationship between placental oxygen transport and fetal brain cortical growth and folding in monochorionic twins.

B-Spline Surface-Based Reduced-Order Modeling of Nonplanar Crack Growth in Structural Digital Twins

Nonplanar crack growth holds a critical role in aeronautical structures, necessitating effective analysis under mixed fatigue loading to assess structural integrity. This study introduces a reduced-order modeling (ROM) method for predicting nonplanar crack growth in structural digital twins. The method’s advantage lies in its representation of the entire crack surface morphology using a B-spline surface, which better captures its impact on crack growth. The symmetric Galerkin boundary element method–finite element method coupling method is adopted as a full-order method to generate the crack database. Isoparametric coordinates of the crack surface and stress intensity factor serve as input and output, respectively, for training the ROM, which integrates -means clustering, principal component analysis, and Gaussian process regression. The proposed approach is demonstrated using a rotorcraft-mast-like component. Results reveal superior fracture mechanics parameter prediction compared to the crack-front-based ROM. Furthermore, the method boasts three orders of magnitude greater efficiency than full-order simulation, enabling its coupling with approaches like Monte Carlo for probabilistic crack growth analysis. Future work entails integrating our method into the probabilistic framework of digital twins.

EP13.16: Comparing the Korean twin growth chart and Korean singleton growth chart and the NICHD twin chart: multicentre retrospective cohort study

EP13.16: Comparing the Korean twin growth chart and Korean singleton growth chart and the NICHD twin chart: multicentre retrospective cohort study

A retrospective study on the physical growth of twins in the first year after birth.

This study analyzed the physical growth of small for gestational age (SGA) and appropriate for gestational age (AGA) twins up to one year after birth. Weight, length, and head circumference data of 0-1 year-old twins were collected from the Child Health Care System from 2010 to 2019. Physical data were presented as Z-scores. Five parameters - growth level of weight, body length, head circumference, growth velocity, and body proportion (weight for length) were compared in twins. A total of 3,909 cases were collected (22.61% SGA, 77.39% AGA). 1. In both groups, WAZ (Weight for age z-score), HCZ (Head circumference for age z-score), and LAZ (Length for age z-score) increased more rapidly in the first 6 months. By one year of age, WAZ, HCZ, and LAZ had reached the normal range, but none had reached the average level of normal singleton children. 2. The mean values of WAZ, HCZ, and LAZ in the AGA group were between -1 and 0, and between -2 and - 1 in the SGA group, in the first year after birth. The SGA group lagged significantly behind the AGA group. The LAZ score of SGA and AGA was lower than the WAZ and HCZ scores. 3. The proportion of preterm AGA was the largest in twins, and the growth rate of preterm AGA was the fastest. Preterm twins had greater growth potential than term twins. However, the growth level of preterm SGA was always low. 4. The WFLZ (Weight for length z-score) in each group was approximately close to 0. The WFLZ of SGA was smaller than that of AGA twins at most time points. After 4 months of age, the WFLZ of twins had a downward trend. The WFLZ of preterm SGA approached -1 at approximately 1 year old. The physical growth of SGA and AGA in twins in the first year can reach the normal range but cannot reach the average level of normal singleton children. More attention should be paid to SGA in twins, especially preterm SGA. We should give proper nutritional guidance after 4 months of age to ensure the appropriate body proportion (weight for length) of SGA in twins. www.chictr.org.cn, CTR2000034761.

Relationship between one-carbon metabolism and fetal growth in twins: A cohort study.

We investigated the associations of one-carbon metabolism (OCM)-related metabolites, including choline, betaine, dimethylglycine (DMG), and methionine with fetal growth of twins. This hospital-based cohort study included dichorionic twin gestations. Blood samples were collected at a median of 14.7 weeks of gestation. Blood plasma metabolite levels were measured using high-performance liquid chromatography-triple quadrupole mass spectrometry. Generalized estimating equations and mixed effects models were used to explore associations between plasma metabolite levels and fetal growth. In total, 115 women with dichorionic diamniotic pregnancies were included. The maternal plasma DMG level was negatively correlated with fetal birth weight (β = -43.5, 95% confidence interval [CI] = -74.1 to -12.8, p < .05) and head circumference (β = -0.23, 95% CI = -0.39 to -0.07, p < .05). Other metabolites were not significantly associated with birth weight, body length, head circumference (HC), or chest circumference. Analysis of the relationships between plasma metabolite levels and fetal biological parameters on ultrasound revealed that the maternal choline level was negatively correlated with fetal abdominal circumference (AC) (β = -0.12, 95% CI = 0.24 to -0.004, p < .05); the maternal DMG level was negatively correlated with fetal AC (β = -0.17, 95% CI = 0.28-0.07, p < .05), femur length (β = 0.02, 95% CI = 0.04-0.003, p < .05), and estimated fetal weight (β = 26.4, 95% CI = -41.6 to -11.2, p < .05), but not with HC. The maternal methionine level was negatively correlated with HC (β = -0.08, 95% CI = -0.14 to -0.02, p < .05). The plasma level of the OCM-related metabolite DMG during the second trimester was negatively correlated with fetal intrauterine growth and birth weight. However, further studies with larger samples are needed.

Dimensional Engineering of Hierarchical Nanopagodas for Customizing Cross‐Scale Magnetic Coupling Networks to Enhance Electromagnetic Wave Absorption

AbstractDimensional engineering of appropriate structure is an effective approach to achieve high‐performance electromagnetic (EM) wave absorption for magnetic materials. However, controllable modulation of the material configuration and a comprehensive understanding of the relationship between structure and loss mechanism remain challenging. Herein, magnetic CoNi pentagonal nanopagodas (PNPs) are ingeniously tailored using a competition orientation strategy, in which high‐density PNPs with sharp corners/edges and hierarchical structure are rooted in situ on the surface of CoNi alloy microsphere. This unique configuration of PNPs originates from the orientation growth of CoNi fivefold twins, which can be effectively regulated by manipulating metal ratio and evolves into flake‐, serrated thorn‐, prismoid‐, and blocks‐like morphologies. Optimized CoNi microspheres with high‐density PNPs exhibit a broad absorption bandwidth of 6.82 GHz at only 1.8 mm thickness. Cross‐scale magnetic coupling networks strengthen magnetic loss ability, magnetocrystalline defects induce dielectric polarization enhancement, which are intuitively confirmed by Lorentz off‐axis electron holography and geometric phase analysis. The underlying mechanism of enhanced magnetic interaction in sharp structure is clearly deciphered by micromagnetic simulation. This study provides methodological guidance for dimensional engineering in fabricating hierarchical magnetic structure and significant insights into the morphology‐dependent loss mechanism for magnetic EM absorption materials.

Statistical analyses of the relationship between inclination angle and twin growth in uniaxial compression of Mg alloys

Inclination angle (IA), which is that between the c-axis of a twin and the global loading direction, satisfactorily captures trends observed in area fractions of both Schmid and non-Schmid twins. The detailed analyses also show that the non-Schmid twins form preferentially in smaller grains compared to that of Schmid ones.

Enhanced strength-ductility synergy in CuSn alloy via tuning Ti content

CuSn alloy is the key raw material for the preparation of Nb3Sn superconducting wires. The properties of Nb3Sn wires can be greatly enhanced by preparing CuSn alloys with high solid solubility of Sn atoms and adding Ti elements. In this paper, the CuSn alloy was prepared by directional solidification with Ti added. Then the homogenization system is determined by calculation and it is expected to improve the structure segregation and mechanical properties of the alloy. Therefore studies the distribution of Ti elements and the relationship between the microstructure evolution and mechanical properties in CuSn alloy. The results indicate that the as-cast structure of the alloy is mainly a core-shell structure, and the grains show a good (001) orientation. It was also found that the Sn-rich phase in the alloy transforms to α-Cu solid solution during homogenization. The mechanical property tests show that the CuSn alloy with 0.3 wt% Ti content has both high strength (409 MPa) and elongation (69%). The main mechanism for enhanced the strength-ductility of the alloy is as follows. The core-shell structure allows sufficient diffusion of Sn atoms during the homogenization treatment, and the CuSn3Ti5 phase hinders the twin growth. As a result, the ductility of the alloy increases significantly. When the Ti content continues to increase until the CuSn3Ti5 phase segregates, causing the alloy's strength and elongation to plummet.