Zr Content Research Articles

Effect of combined additions of Sc, Zr and Ti on hot-cracking resistance and precipitation behaviour in Al-Mg alloy by L-PBF

The request for high-performance aluminum components prompts research into innovative alloys compatible with laser-based additive manufacturing processes, leveraging grain refiners in their composition to mitigate hot-cracking and enhance strength. While the addition of Sc and Zr in Al-Mg alloys has been widely investigated, the high cost and supply risks associated with Sc necessitate reducing its amount and replacing, at least partially, with other inoculants. In this preliminary study, the amount of Sc replaceable with different concentrations of Zr or Ti is evaluated investigating the laser powder bed fusion processability of three powder feedstocks: a pre-alloyed Al-Mg-Zr-Sc powder, a blend of the previous alloy with addition of Zr particles, and a further blend of an alloy depleted of Zr with added Ti particles. The experimental analyses on the laser-processed alloys showed that the standard and the Zr-enriched alloys featured a bimodal microstructure free from cracks with fine equiaxed grains at the edge of the molten pools and coarser grains at their centers. In the alloy variant depleted in Zr with addition of Ti particles a columnar structure was observed and hot-cracks appeared. Thermodynamic simulations of phase formation allowed defining the precipitation kinetics during solidification and direct aging, showing increased precipitation in alloys with higher Zr content, while the presence of Ti resulted in sluggish precipitation. Experimental aging tests demonstrated significant increases in microhardness, with peak values of the modified alloys achieved after 12 h at 375 °C.

Effect of Zr content on microstructure, mechanical properties and corrosion behaviour in hydrochloric acid for as-cast Ti-Zr alloy

In this work, the aim was to develop a Ti alloy with improved mechanical properties and improved corrosion resistance in acidic environments. The results show that the thicknesses of the α' phase first increases and then decreases with increasing Zr content. The elastic modulus (E) first decreases and then increases, while the hardness (H), wear resistance, and plasticity index (Up/Ut) gradually increase. Moreover, the corrosion resistance of Ti-Zr alloys was improved significantly as the Zr concentration increased, which was mainly reflected in an increase in the polarization resistance and a decrease in the corrosion rate.

Plastic quasicrystal-containing alloys prepared by annealing pseudo-high entropy Zr70–75(Al, Ni, Cu, Ag)25–30 glassy alloys

A glassy (G) phase was formed for Zr-rich Zr70–75(Al, Ni, Cu, Ag)25–30 (atomic percent, at.%) melt-spun alloy ribbons. These glassy alloys exhibit the glass transition, followed by a supercooled liquid region and then three-stage crystallization. The glass transition temperature and the onset temperature for the first-stage crystallization (Tx1) decrease from 630 to 668 K, respectively for the 70Zr alloy to 619 and 652 K, respectively for the 75Zr alloy. The first-stage exothermic peak is due to the precipitation of an icosahedral quasicrystal (IQ) phase. The IQ particle size decreases from 10 nm to 6 nm with increasing Zr content from 70at.% to 74at.%. The [G + IQ] phases change to Zr2Ni + Zr2(Cu, Ag) phases after the second exothermic peak and then Zr2Ni + Zr2(Cu, Ag) + Zr5Al3 phases after the third stage. It is noticed that the as-spun glassy alloy ribbons as well as the annealed [G + IQ] phase ribbons exhibit good bending plasticity. Furthermore, the 70Zr thicker ribbons also exhibit high tensile fracture strength of 1090–1187 MPa and plastic elongation of 0.17 %–0.42 %. The fracture mode is similar to that of ordinary bulk metallic glasses. The Vickers hardness (Hv) is 480 for 70Zr alloy and decreases to 436 for 75Zr alloy. The precipitation of IQ phase causes a significant increase in Hv to about 554. The formations of glassy alloys with high Zr contents of 70at.%–75at.% by melt spinning as well as the [G + IQ] phase alloys with good bending plasticity by annealing hold promise for the creation of a new type of engineering material, transcending mere academic novelty.

Determination of threshold values and heavy metal pollution assessment of soils in an industrial area in Ghana.

Industrial activities have the potential to pollute soils with a wide variety of heavy metals (HMs). In Ghana, however, assessment of HM pollution of soils in industrial areas remains limited. Accordingly, HM soil pollution in one of the industrial areas in Accra, Ghana was assessed. Soil samples were taken and analysed forHMs, including Fe, Zr, Zn, Ti, Sr, Rb, Mn, Pb, Cu, and Co, using X-Ray Fluorescence (XRF). HM geochemical threshold values (GTVs) were determined to establish soil HM pollution levels and identify areas needing remediation. Furthermore, risk assessments wereconducted to evaluate the potentialecological and human health risks associated with these metals.The mean concentrations of Fe, Zn, Rb, Sr, Zr, Ti, Mn, Co, Cu, and Pb in the soils were: 27133.83, 147.72, 16.30, 95.95, 307.11, 4663.66, 289.85, 418.54, 44.97, and 112.88 mg/kg, respectively. Generally, the concentrations of HMsdecreased with depth, although some lower layers exhibited elevated HM levels. Soil pollution levels were categorized as low for Fe, Rb, Zr, Ti, Mn, Co, and Cu; moderate for Sr and Zn; and considerable for Pb. Notably, the northwestern part of the study area displayed a considerable to very high degree of HM contamination. While HMs in the soils posed low ecological risk, the human health risk assessment indicated potential health effects from Co, particularly in children. The presence of HMs in the soils was noted to originate from both natural geological phenomena and human activities, including industrial operations, agricultural practices, landfill activities, and vehicular emissions.

Properties of spray pyrolysis deposited Zr-doped ZnO thin films and their UV sensing properties

This study investigated the characteristics of Zr-doped ZnO thin films with varying Zr doping concentrations. X-ray diffraction (XRD) analysis confirmed the presence of the ZnO hexagonal phase without any additional phases detected. The crystallite size was determined using Scherrer’s equation and Halder-Wagner equation, revealing distinct trends as the Zr content increased. The impact of Zr doping concentration on structural properties such as lattice parameters was also explored. Field emission scanning electron microscopy (FE-SEM) images indicated agglomeration, with a peak value observed at Zr-5 wt% of 175 nm that decreased at higher Zr contents. Optical properties exhibited minor variations with increasing Zr content, with the maximum band gap recorded at 3.28 eV for Zr-7 wt% and Zr-10 wt% films. Utilizing the Spitzer-Fan model, the high-frequency dielectric constant peaked at 14.26 for Zr-7 wt% films. Optical mobility displayed fluctuations with rising Zr content. Direct current (DC) conductivity results unveiled two donor levels in the deposited films, showcasing minimum activation energies of 0.23 and 0.165 eV for high and low-temperature ranges in the Zr-3 wt% film. Furthermore, the response to UV light illumination at a wavelength of 365 nm was examined, revealing notable changes in rise and decay times with varying Zr content.

Effects of Zr content on microstructure and properties of 9Cr ferritic/martensitic steel

The effect of the Zr content range in 0.03–0.63 wt% on the microstructure, mechanical properties and high-temperature oxidation behaviors of 9Cr ferritic/martensitic (FM) steels was investigated. The microstructural evolution of steels was studied using Thermo-Calc software, SEM, EBSD and TEM technologies. A full martensite structure was obtained in steels with various Zr contents. The small-sized M23C6 decrease and the larger-sized Zr(C, N) increase with the increasing Zr content, which leads to the increase of martensitic lath width and martensitic block size. The proper Zr content can enhance the oxidation resistance of steel, but Zr addition will reduce the mechanical properties. The decrease in strength and hardness can be ascribed to the reduction of precipitation strengthening and gain size strengthening. The increase in Zr content promotes the formation of Zr oxides, which reduces the formation of MnCr2O4 oxides and Cr2O3 oxides, and finally improves the oxidation resistance of steels.

Mineralization of Zr-REE-Y in the Ngaoumbol iron formations, central Cameroon: Insights from petrography, mineral chemistry and whole rock geochemistry

The increasing importance of rare earth elements (REE) and critical metals in contemporary society has led us to investigate the mineral potential of the Ngaoumbol area, located within Cameroon's Central African Fold Belt (CAFB). In this study, we have conducted a comprehensive analysis that includes petrography, whole rock geochemistry, and mineral chemistry, along with the application of an outlook coefficient known as Koult, with the aim to evaluate the prospectivity of the Ngaoumbol iron formations as a potential source of REE-Y resources. This coefficient is defined as the ratio of the relative abundance of critical Rare Earth Elements to the relative abundance of excess REE. The iron formations in the Ngaoumbol area are fine-to medium-grained foliated rocks with alternating magnetite and actinolite bands and quartz bands, suggesting a sedimentary parentage. These rocks have an average REE-Y content of 1438.43 ppm and a Koult of 0.77, indicating their potential as raw sources for REE. Furthermore, the investigated samples exhibit high average Zr content (7748 ppm), suggesting that the rocks may host potentially economic Zr ore. The Zr-REE-Y mineralization in the Ngaoumbol area is hosted in detrital zircon, monazite and xenotime, probably deriving from the weathering of alkaline/subalkaline rocks surrounding the deposits. Our findings suggest that the Ngaoumbol area has promising REE and Zr resources. However, further exploration and evaluation are necessary to determine the extent and economic viability of these resources.

Maximizing the Processing of Polymetallic Concentrates via Actinide Separation and Rare Earth Retrieval

During the last decades, the growing demand for rare earth elements (REEs) has led to numerous recent studies to recover these elements from various bearing ores and wastes. Therefore, the recovery of REEs from Ras Baroud polymetallic concentrate has been investigated in the current study. Physical beneficiation for the Ras Baroud pegmatite sample was carried out, yielding a concentrate for euxenite (Y), fergusonite (Y), xenotime (Y), monazite (Ce), allanite, thorite, uranothorite, and Hf-zircon, which resulted in raising the concentrations of rare earth elements, Th, Zr, U, and Ti in the sample. Fusion digestion processes with sodium hydroxide were studied using the Conceived Predictive Diagonal (CPD) technique. The three experimental digestion groups proved the dissolution of 99.9, 95.6, 99.9, 52.5, and 0.47% for REEs, Th, U, Ti, and Zr, respectively, under fusion conditions of 723 K, 120 min, 1/1.5 ore/alkali ratio, and − 100-μm particle sizes. Fusion kinetics, isotherms, and thermodynamics were investigated using several suggested models, namely, pseudo reversible first order, uptake general model, and shrinking core model which matched well with the experimental digestion results. Selective recovery of actinide content from REE content of the digested concentrate chloride solutions was accomplished using solvent extraction with di-2-ethyl hexyl phosphoric acid. About 99.9, 99.9, and 4.2% extraction efficiencies for Th, U, and REEs were performed, respectively, using 0.3 mol/L solvent concentration in kerosene as a diluent, 1/2 organic to aqueous ratio, an aqueous pH of 0.2, and 15-min contact time. Thorium and uranium ions were stripped with sulfuric acid solution 2.5 mol/L with 94 and 98% stripping efficiency, respectively. A highly purified REE precipitate was obtained from the raffinate solutions. Zircon mineralization tailings were obtained as a by-product through the alkaline digestion process.

Development of new materials for electrothermal metals using data driven and machine learning.

After adopting a combined approach of data-driven methods and machine learning, the prediction of material performance and the optimization of composition design can significantly reduce the development time of materials at a lower cost. In this research, we employed four machine learning algorithms, including linear regression, ridge regression, support vector regression, and backpropagation neural networks, to develop predictive models for the electrical performance data of titanium alloys. Our focus was on two key objectives: resistivity and the temperature coefficient of resistance (TCR). Subsequently, leveraging the results of feature selection, we conducted an analysis to discern the impact of alloying elements on these two electrical properties.The prediction results indicate that for the resistivity data prediction task, the radial basis function kernel-based support vector machine model performs the best, with a correlation coefficient above 0.995 and a percentage error within 2%, demonstrating high predictive capability. For the TCR data prediction task, the best-performing model is a backpropagation neural network with two hidden layers, also with a correlation coefficient above 0.995 and a percentage error within 3%, demonstrating good generalization ability. The feature selection results using random forest and Xgboost indicate that Al and Zr have a significant positive effect on resistivity, while Al, Zr, and V have a significant negative effect on TCR. The conclusion of the composition optimization design suggests that to achieve both high resistivity and TCR, it is recommended to set the Al content in the range of 1.5% to 2% and the Zr content in the range of 2.5% to 3%.

Evolution of Structure and Texture Formation in Thermomechanically Treated Ti-Zr-Nb Shape Memory Alloys

Biomedical Ti-22Nb-6Zr, Ti-18Zr-15Nb, and Ti-41Zr-12Nb (at.%) shape memory alloys were subjected to cold rolling (CR) and subsequent post-deformation annealing (PDA). The evolutions of phase and structure states, crystallographic texture, and crystallographic limit of recovery strain were studied using EBSD, TEM, and XRD analyses. The study found that CR (e = 1.5) and PDA at 800 °C for 30 min results in fine- and coarse-grained structures. Severe CR (e = 3.0) and PDA at 550 °C for 5 min results in a recrystallized, equiaxed, predominantly ultrafine-grained structure of the β-phase with a small amount of low-angle boundaries. Increasing the degree of CR from moderate (e = 0.3) to severe (e = 3.0) results in a favorable strong {111}β<110>β recrystallization texture. Alloys with low Zr content are more susceptible to this type of crystallographic texture formation during TMT, primarily due to a higher Nb content. The Ti-41Zr-12Nb alloy shows the highest crystallographic limit of recovery strain (εrmax ≈ 6%). The limit decreases to ≈5% (for Ti-18Zr-15Nb) and ≈3% (for Ti-22Nb-6Zr) when transitioning from high- to low-Zr alloys. The transition of Ti-Zr-Nb alloys from coarse-grained to ultrafine-grained structures of the β-phase and a decrease in grain size do not affect the crystallographic limit of recovery strain in the studied grain size ranges.

Strigolactones affect the yield of Tartary buckwheat by regulating endogenous hormone levels

BackgroundAs a newly class of endogenous phytohormones, strigolactones (SLs) regulate crop growth and yield formation by interacting with other hormones. However, the physiological mechanism of SLs affect the yield by regulating the balance of endogenous hormones of Tartary buckwheat is still unclear.ResultsIn this study, a 2-year field experiment was conducted on Tartary buckwheat (Jinqiao 2) to study the effects of different concentrations (0, 10, and 20 µmol/L) of artificial synthetic analogs of SLs (rac-GR24) and inhibitor of SL synthesis (Tis-108) on the growth, endogenous-hormone content, and yield of Tartary buckwheat. The main-stem branch number, grain number per plant, grain weight per plant, and yield of Tartary buckwheat continuously decreased with increased rac-GR24 concentration, whereas the main-stem diameter and plant height initially increased and then decreased. Rac-GR24 treatment significantly increased the content of SLs and abscisic acid (ABA) in grains, and it decreased the content of Zeatin (Z) + Zeatin nucleoside (ZR). Conversely, Tis-108 treatment decreased the content of SLs and ABA but increased the content of Z + ZR. Results of correlation analysis showed that the content of ABA and SLs, the ratio of SLs/(Z + ZR), SLs/ABA, and ABA/(Z + ZR) were significantly negatively correlated with the yield of Tartary buckwheat, and that Z + ZR content was significantly positively correlated with the yield. Regression analysis further showed that ABA/ (Z + ZR) can explain 58.4% of the variation in yield.ConclusionsIn summary, by adjusting the level of endogenous SLs in Tartary buckwheat, the balance of endogenous hormones in grains can be changed, thereby exerting the effect on yield. The results can provide a new agronomic method for the high-yield cultivation of Tartary buckwheat.

Revealing the mechanical behavior of Ti48-xZrxHf26Nb26 high-entropy alloy through zirconium content variations

Refractory high-entropy alloys (RHEAs) composed of Ti, Zr, Hf, and Nb have emerged as promising materials for high-temperature aerospace applications due to their exceptional balance of strength and toughness, coupled with a reduced density and softening resistance. This study delves into the influence of alloy composition on the mechanical properties, a pivotal aspect in the design of RHEAs. We investigate a series of Ti48-xZrxHf26Nb26 (x = 14, 18, 22, 26, 30, 34) alloys, prepared through suction casting and homogenization treatments. The phases, microstructure, and fracture morphology of these alloys are analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD), subsequent tensile tests provide insights into the strength and elongation characteristics of alloys. The homogenized alloys consistently exhibit one BCC phase with equiaxed grains, whereas the fracture mode shifts from intergranular to transgranular, and return to intergranular as the Zr content increases. Experimental results reveal an asymmetry mechanical behavior, alloys with higher Ti content display superior toughness (elongation 17.83 % for Ti = 34 at%) compared to those with higher Zr content (elongation 16.05 % for Zr = 34 at%). Among them, the Ti22Zr26Hf26Nb26 alloy achieves the peak tensile strength of 695.25 MPa, indicating an inverse relationship between strength and toughness. Solid-solution strengthening and chemical short-range orderings emerge as the predominant contributors to the overall strength of the TiZrHfNb alloys. To gain a deeper understanding of the mechanical behavior at the atomic scale, we performed first-principles calculations to investigate the elastic properties and charge density of Ti48-xZrxHf26Nb26 alloys in the BCC structure. These calculations shed light on the underlying mechanisms governing the strength and toughness behavior. The present work offers valuable insights into the design of mechanical properties of TiZrHfNb RHEAs, serving as a paradigm for future materials development in this field.

One-Step Synthesized Solid Acid Catalyst with High Zr Content for Efficient and Green PET Degradation in Supercritical CO2

One-Step Synthesized Solid Acid Catalyst with High Zr Content for Efficient and Green PET Degradation in Supercritical CO₂

Unravelling the genesis and depositional setting of Neoproterozoic banded iron formation from central Eastern Desert, Egypt

The Neoproterozoic banded iron formations (BIFs) are widely occurred in the Egyptian Eastern Desert. This study integrates field observations, petrographic studies, geochemical data, and lead isotopes to construct the genesis and depositional environment of Wadi El-Mis hama BIF deposits. The iron layers, primarily of oxide facies within a volcano-sedimentary sequence, comprise magnetite-rich beds alternating with jaspilite or silicate laminae. The studied BIFs exhibit a dominant composition of SiO2 and Fe2O3t with relatively low contents of TiO2 and Al2O3. The positive correlation of REEs (La, Sm, Yb) with Zr and low concentrations of HFSEs (Ta, Nb, Th, Hf) indicate a primary formation mechanism of chemical precipitation, maintaining original geochemical signatures. Geochemical patterns show depletion in LREEs, enrichment in HREEs (La/YbPAAS = 0.08–0.12), and positive La anomalies (La/LaPAAS = 1.15–8.57), consistent with seawater influence. Additionally, various geochemical discrimination diagrams supported by elevated super-chondritic Y/Ho values (29.6–38.7), weak positive Eu anomalies, and low contents of transition metals (Cu and Zn), point to the interaction of low-temperature (<200°C) hydrothermal fluids (bearing Fe and Si) with seawater during the deposition of the BIFs. The lack of significant negative Ce anomalies along with low Ni/Co, U/Th, and Cu/Zn ratios, imply that the iron mineralization was precipitated from dysoxic to oxic conditions. The geochemical and Pb isotopic data suggest that the iron deposits formed in an extensional geodynamic setting (intra-oceanic arc basin environment) due to the subduction of the Mozambique Plate, with signatures closely matching other Precambrian Algoma-type BIFs.

Optimized hydrogen storage properties of Ti–Zr–Mn–VFe-based alloys by orthogonal experiment for upscaled production

Ti–Mn-based hydrogen storage alloys have been widely developed for hydrogen compressors and storage because of their excellent hydrogen storage properties. However, there is still a need to develop a high-capacity hydrogen storage based on low-cost and large-scale preparation. Herein, cheap VFe80 intermetallic alloy is employed to replace the expensive V, and Ti–Zr–Mn–VFe-based alloys ((Ti1-yZry)1+xMn1.88-z(VFe)z, x = 0, 0.05, 0.1, y = 0.05, 0.1, 0.15, z = 0.34, 0.44, 0.54) with mainly C14 Laves phase structure were designed and prepared to optimize the composition by an orthogonal experiment. According to the orthogonal analysis, it is found that the maximum hydrogen storage capacity and hysteresis factor mainly are controlled by the content of VFe80 in the Ti–Zr–Mn–VFe-based alloys. The over-stoichiometry of A-side governs the plateau slope, and the content of Zr decreases hydrogen plateau pressure. The optimal Ti0.9Zr0.1Mn1.44(VFe)0.44 alloy achieves a revisable hydrogen storage capacity of 1.73 wt% with low plateau hysteresis factor (0.49) and plateau slope factor (0.73) at room temperature, the dehydrogenation enthalpy and entropy values respectively are 33.92 kJ/mol and 120.64 J/(mol∙K), which exhibits the best overall hydrogen storage properties. Furthermore, the optimal alloy was successfully produced on a large scale, which provides empirical value for upscaled production of AB2 Laves-phase hydrogen alloys.

Magmatic–hydrothermal stage recorded by mica zonation and Nb–Ta–W–Sn mineralization: New insight into the genesis of highly evolved Songshugang Nb–Ta deposit (Jiangxi, SE China)

The role of magmatic and hydrothermal processes in niobium-tantalum mineralization is still controversial and has been limited by a lack of mineralogical records in the evolving magmatic–hydrothermal system. Micas as essential rock-forming minerals and comprise the amount of elements (especially rare-metal elements), become one of the ideal indicator. The Songshugang rare-metal granite (RMG) located in the southern part of Jiangxi Province, China, is renowned as the largest tantalum reservoir in South China. The albite–topaz–K-feldspar granite is the major granite, with layers of pegmatite, topaz-K-feldspar granite, and greisen overlay on it. It is the typical highly evolved peraluminous with low phosphorous RMGs (PLP-type) according to geochemistry. The Songshugang pluton preserves analogical characters in topaz-albite-K feldspar granites and topaz-K feldspar granite, and partly reserves in greisen. Detailed petrographic, mineralogy, and chemical composition study of zoned mica and accessory Nb–Ta minerals suggest that zinnwaldite and Nb-Ta oxides have experienced magmatic fractionation with gradually decrease of K/Rb and Nb/Ta ratio in prismatic zinnwaldite and columbite-(Fe). The leap of Rb (Rb2O up to 4.08 wt%) and Ta (Ta# up to 0.29) at the rim of zinnwaldite and columbite is likely attributed to supersaturation. Afterwards the overgrowth of Rb-deficit zinnwaldite (0.56–0.72 wt% Rb2O) is coeval with the Ta-highest wodginite, taking place during the magmatic-hydrothermal transition associated with a fluid-melt interaction in hydrosaline melt. The ascent of fluxing elements contributes to the formation of hydrothermal zinnwaldite and cassiterite through greisenization. The systemic coupling mineralization of zinnwaldite and Nb–Ta oxides altogether record the both the melt-driven and fluid-driven processes in highly evolved Songshugang deposit that is critical for rare-metal mineralization. The Songshugang displays a great similarity to the typical PLP RMGs Cínovec cupola in geochemistry, which are metaluminous to peraluminous, containing low phosphorous, intermediate REE, Zr, Hf, and Th content. But Songshugang has experienced strong supersaturation; the latter is more akin to highly evolved melts alike Yichun or Beauvoir. The strong supersaturation and crystallization demonstrate its discrepant mineralization mechanism in Songshugang RMGs.

Optimizing the Heat Treatment Method to Improve the Aging Response of Al-Fe-Ni-Sc-Zr Alloys.

This work has studied the co-addition of Sc and Zr elements into the Al-1.75wt%Fe-1.25wt%Ni eutectic alloy. The changes in the microstructure, electrical conductivity, and Vickers hardness of the Al-1.75wt%Fe-1.25wt%Ni-0.2wt%Sc-0.2wt%Zr alloy during heat treatment were studied. The results showed that two-step aging can effectively improve the aging response of the alloy over the single-step aging method. This was ascribed to the minimization of the diffusion difference between Sc and Zr elements. Furthermore, the homogenization treatment can also improve the aging response of the alloy by alleviating the uneven distribution of Sc and Zr. Nevertheless, the micro-alloyed elements exceeded the solid solubility limit in the Al-1.75wt%Fe-1.25wt%Ni-0.2wt%Sc-0.2wt%Zr alloy, and their strengthening effect has ever achieved the best prospect. Finally, both Sc and Zr contents were reduced simultaneously, and the aging response of the Al-1.75wt%Fe-1.25wt%Ni-0.15wt%Sc-0.1wt%Zr alloy was improved by optimized heat treatment. The underlying mechanisms for this alloy design and the corresponding microstructure-mechanical property relationship were analytically discussed.

Morphological, cytological, physiological, and molecular evidence to explain how underground fleshy roots expand in herbaceous peony (Paeonia lactiflora Pall.)

The fleshy roots of herbaceous peonies serve as vital storage organs and are the primary source material for Chinese herbal medicine. Moreover, in certain cultivars, these roots can be propagated by root cuttings. However, the specific mechanisms governing the expansion and development of fleshy roots in herbaceous peonies currently remain unclear. To elucidate patterns of changes during the enlargement and development of herbaceous peony fleshy roots, this study assessed fleshy roots in six growth and development periods (P1–P6). By integrating environmental monitoring data, morphological, cytological, physiological and biochemical, as well as molecular characteristics across these developmental periods were compared. Both precipitation and temperature influenced the development of fleshy roots. The fastest enlargement of fleshy roots occurred under the following growth conditions: daily average precipitation = 5.6 mm; monthly average air temperature = 25.6°C; monthly average soil temperature = 26.3°C. Phloem and xylem, produced by the activity of vascular cambium, are important components of fleshy roots. Secondary xylem thickness consistently increased across the six developmental periods, resulting in the radial expansion of fleshy roots. When average monthly air and soil temperatures were about 26°C, starch accumulated gradually in fleshy roots, and carbohydrates were mostly starch-based. However, when the average monthly air and soil temperatures decreased to about 11.0°C, soluble sugar content increased. Endogenous hormones such as IAA, ZR, GA3, MeJA, and ABA played regulatory roles throughout the development of fleshy roots, and their levels and dynamic equilibrium were correlated with expansion rate. Elevated IAA and ZR content, and stabilized IAA/ABA and MeJA/ABA ratios, favored fleshy root expansion. Trends in the expression of three genes that play key roles in the expansion of fleshy roots (PlEXLB3, PlAUX1 and PlWRKY13) were consistent with morphological and physiological data, but PlHXK1 and PlIPT3 also play important roles. These findings lay a foundation for studying, in greater depth, the regulatory mechanisms governing the enlargement of herbaceous peony fleshy roots, and offer practical advice pertaining to field cultivation and management practices of this ornamental plant.

Hf-Nd isotope decoupling in S-type granitoids caused by disequilibrium melting of metasedimentary rocks: Evidence from the North Qinling Terrane, Central China

The intrinsic assumption of radiogenic isotope tracing is that isotope systems maintain equilibrium between melt and source. However, this assumption is not naturally correct, particularly for S-type granites, which are formed by partial melting of metasedimentary rocks. The S-type metagranites from the North Qinling Terrane show various degrees of HfNd isotope decoupling and discrepancies between whole-rock and zircon Hf isotopes. Zircon UPb dating yields emplacement ages from 946 to 890 Ma. Their high δ18O values, (87Sr/86Sr)i ratios, and negative εNd(t) values overlapped with metasedimentary rocks in the Qinling Group imply that they are derived from partial melting of the Qinling Group. The low Rb/Ba, Rb/Sr, Al2O3/TiO2, and high CaO/Na2O ratios indicate that their sources are metagraywackes. The negative correlation between decoupling degrees of HfNd isotopes and Zr concentrations suggests that the incomplete dissolution of zircon during partial melting results in the decoupling. The discrepancy between whole-rock and zircon Hf isotopes can be attributed to the combined effect of incomplete dissolution of zircons and the release of various Hf isotope compositions from partly dissolved inherited zircons to local melts. The compiled literature data suggest that whole-rock HfNd isotope decoupling of most metagraywacke-derived S-type granites is caused by incomplete melting of zircons, whereas those of metapelite-derived S-type granites may be controlled by both incomplete melting of zircons and source inheritance.

Design multifunctional Mg–Zr coatings regulating Mg alloy bioabsorption

Magnesium (Mg) alloys are widely used for temporary bone implants due to their favorable biodegradability, cytocompatibility, hemocompatibility, and close mechanical properties to bone. However, rapid degradation and inadequate strength limit their applicability. To overcome this, the direct current magnetron sputtering technique is employed for surface coating in Mg-based alloys using various zirconium (Zr) content. This approach presents a promising strategy for simultaneously improving corrosion resistance, maintaining biocompatibility, and enhancing strength without compromising osseointegration. By leveraging Mg's inherent biodegradability, it has the potential to minimize the need for secondary surgeries, thereby reducing costs and resources.This paper is a systematic study aimed at understanding the corrosion mechanisms of Mg–Zr coatings, denoted Mg-xZr (x = 0–5 at.%). Zr-doped coatings exhibited columnar growth leading to denser and refined structures with increasing Zr content. XRD analysis confirmed the presence of the Mg (00.2) basal plane, shifting towards higher angles (1.15°) with 5 at.% Zr doping due to lattice parameter changes (i.e., decrease and increase of “c” and “a” lattice parameters, respectively). Mg–Zr coatings exhibited “liquidphilic” behavior, while Young's modulus retained a steady value around 80 GPa across all samples. However, the hardness has significantly improved across all samples’ coating, reaching the highest value of (2.2 ± 0.3) GPa for 5 at.% Zr. Electrochemical testing in simulated body fluid (SBF) at 37 °C revealed a significant enhancement in corrosion resistance for Mg–Zr coatings containing 1.0–3.4 at.% Zr. Compared with the 5 at.% Zr coating which exhibited a corrosion rate of 32 mm/year, these coatings displayed lower corrosion rates, ranging from 1 to 12 mm/year. This synergistic enhancement in mechanical properties and corrosion resistance, achieved with 2.0–3.4 at.% Zr, suggests potential ability for reducing stress shielding and controlled degradation performance, and consequently, promising functional biodegradable materials for temporary bone implants.