Ti Nb Research Articles

Unprecedented Superhigh‐Rate and Ultrastable Anode for High‐Power Battery via Cationic Disordering

AbstractHigh‐power lithium‐ion batteries (LIBs) are critical for power‐intensive applications; however, their development is largely hindered by the lack of anode materials that have stability and high capacity at high charging/discharging rates. Herein, a cationic disordering strategy is reported to build an ideal high‐power anode with boosted intercalation kinetics and a stable framework. A novel titanium niobate (TiNb2O7) anode with unique predistorted Nb(Ti)O6 octahedrons (pd‐TNO) is developed by introducing cation disorder, which allows ultrafast Li+ storage within seconds and exceptional stability over long cycling at high rates. The pd‐TNO delivers an outstanding specific capacity of 153 mAh g−1 at 100 C, 20 times higher than that of conventional TNO anodes without cationic disordering, and retains 42.8% of the capacity after 15,000 cycles. Using the pd‐TNO anode, a high‐power LIB with an unprecedented power density of 91,197 W kg−1 at 200 C, which is approximately eight times higher than that of the advanced commercial high‐power anode Li4Ti5O12 (11,813 W kg−1 at 50 C), is demonstrated. Importantly, the pd‐TNO is prepared under ambient conditions via a high‐throughput process, and it exhibits considerable potential for scalability for practical applications.

Microstructure and mechanical properties evolution during thermomechanical processing of a Ti–Nb–Zr–Ta–Sn–Fe alloy

During the last decades, Titanium-based alloys have shown a suitable combination of strength, ductility, corrosion and biocompatibility properties, that marks them as suitable implant materials for biomedical applications. In this study, a Ti–30Nb–12Zr–5Ta–2Sn-1.25Fe (wt%) alloy was produced by melting in a cold crucible induction in levitation furnace, deformed by cold rolling, with a total deformation degree (thickness reduction) of 50%, in five equal steps, and solution treated at 850 °C, with progressive treatment durations, from 5min to 20min, in 5min increments. The initial microstructure is homogenous, consisting of equiaxed β-Ti phase grains showing an average grain size close to 135 μm. The applied cold deformation induces changes in the microstructure, which shows the presence of deformation bands, twins, dislocation bands and of an increased crystal defects density and residual strain–stress fields. Also, an increase in strength and decrease in ductility properties are noticed due to the strain hardening. The applied solution treatment leads to the regeneration of the microstructure, the obtained microstructure showing homogeneous equiaxed β-Ti phase grains, with an average grain size between 60 μm and 80 μm, depending on the solution treatment duration. Also, a decrease in strength and increase in ductility properties are noticed due to the lowering of the crystal defects density, remanent strain–stress fields and an increase of the average grain size.

Formation and Thermal Stability of the ω-Phase in Ti-Nb and Ti-Mo Alloys Subjected to HPT.

This paper discusses the features of ω-phase formation and its thermal stability depending on the phase composition, alloying element and the grain size of the initial microstructure of Ti–Nb and Ti–Mo alloys subjected to high-pressure torsion (HPT) deformation. In the case of two-phase Ti–3wt.% Nb and Ti–20wt.% Nb alloys with different volume fractions of α- and β-phases, a complete β→ω phase transformation and partial α→ω transformation were found. The dependence of the α→ω transformation on the concentration of the alloying element was determined: the greater content of Nb in the α-phase, the lower the amount of ω-phase that was formed from it. In the case of single-phase Ti–Mo alloys, it was found that the amount of ω-phase formed from the coarse-grained β-phase of the Ti–18wt.% Mo alloy was less than the amount of the ω-phase formed from the fine α′-martensite of the Ti–2wt.% Mo alloy. This was despite the fact that the ω-phase is easier to form from the β-phase than from the α- or α′-phase. It is possible that the grain size of the microstructure also affected the phase transformation, namely, the fine martensitic plates more easily gain deformation and overcome the critical shear stresses necessary for the phase transformation. It was also found that the thermal stability of the ω-phase in the Ti–Nb and Ti–Mo alloys increased with the increasing concentration of Nb or Mo.

Microstructure, mechanical properties and biocompatibility of laser metal deposited Ti–23Nb coatings on a NiTi substrate

To simultaneously obtain superior superelasticity and biological properties, single- and multi-layer Ti–23Nb coatings were deposited on a cold-rolled NiTi substrate using laser metal deposition (LMD). The microstructure of the single-layer coating consisted of a cellular structure with a grid size of ∼300 μm in the eutectic layer, strip structures and prior β-(Ti, Nb) phases surrounded by the Ti2Ni(Nb) phase in the Ni diffusion zone. In contrast, the microstructure of the multi-layer coating consisted of α′, α′′, and prior β phases, which arise from the partition of Nb. Compared with the NiTi substrate, the Ni ion release concentration of the single-layer coating is reduced by 45% with similar nano-mechanical behavior, i.e. a nanohardness, H, of ∼4.0 GPa, a reduced Young's modulus, Er, of ∼65 GPa, an elastic strain to failure, H/Er, of ∼0.06, a yield stress, H3/Er2, of ∼0.016 GPa, and a superelastic strain recovery, ηsr, of ∼0.3. The reduction of Ni ion concentration for multi-layer coating after 35 days is even better at up to 62%, but at the cost of a degradation in the mechanical properties. The LMD coatings have a high dislocation density, and their creep is controlled by dislocation movement.

Nb–Ta mineralization in Ti-oxide minerals from the Bagolyhegy Metarhyolite Formation (Bükk Mountains, NE Hungary)

Abstract The foliated low-grade metamorphic rocks of the Triassic Bagolyhegy Metarhyolite Formation, mainly of pyroclastic origin, host post-metamorphic quartz-albite veins containing abundant tourmaline and occasionally rutile/ilmenite. The study of the Ti-oxide-mineralized veins with SEM-EDX revealed an unusual mineral assemblage comprising fine-grained Nb–Ta-bearing oxides (columbite-tantalite series, fluorcalciomicrolite and other Nb–Ti–Y–Fe-REE-oxide minerals) intergrown with Nb-rich polymorphs of TiO2 (anatase, rutile), ilmenite and zircon enriched with hafnium. This high field strength elements (HFSE)-bearing paragenesis is unexpected in this lithology, and was not described from any formation in the Paleozoic-Mesozoic rock suite of the Bükk Mountains (NE Hungary) before. The host metavolcanics are significantly depleted in all HFSE compared to the typical concentrations in felsic volcanics and the mineralized quartz-albite veins have even lower Ti–Nb–Ta concentration than the host rock, so the mineralization does not mean any enrichment. From proximal outcrops of the Triassic Szentistvánhegy Metavolcanics, potassic metasomatized lenses with albite-quartz vein fillings containing rutile/ilmenite are known. We studied them for comparison, but they only contain REE mineralization (allanite-monazite-xenotime); the Nb–Ta-content of Ti-oxide minerals is undetectably low. LA-ICP-MS measurements for U–Pb dating of Hf-rich zircon of the Nb–Ta-rich mineral assemblage gave 71.5 ± 5.9 Ma as lower intercept age while dating of allanite of the REE mineralized quartz-albite veins gave 113 ± 11 Ma as lower intercept age. The REE-bearing vein fillings formed during a separate mineralization phase in the Early Cretaceous, while the Nb–Ta mineralization was formed by post-metamorphic alkaline fluids in the Late Cretaceous., controlled by fault zones and fractures.

Influence of nano-Y2O3 addition on the mechanical properties of selective laser melted Inconel 718

There has been limited research on Ni-based oxide dispersion strengthened (ODS) alloys. To alleviate the drawbacks of the traditional ODS alloy manufacturing method, selective laser melting technology was chosen in this study to successfully manufacture ODS Inconel 718-Y2O3 alloys. Y2O3 nanoparticles were mixed with Inconel 718 powder at different weight percentages (0, 0.4, 1.0, and 1.5 wt%) using low energy ball milling. Using this method, the Y2O3 nanoparticles were homogeneously distributed throughout the Inconel 718 matrix. The mechanisms, in which the added Y2O3 nanoparticles combined with carbonitride precipitates to form complex precipitates consisting of Ti–Nb–Y–N–C–O were discussed. At 1.0 wt% of Y2O3 addition, a finer Laves phase was obtained, along with some grain refinement effect. The optimum amount of nanoparticles was found to be 1.0 wt% in which, interestingly, the material's elongation improved instead of its strength. On the other hand, 1.5 wt% of Y2O3 addition was found to be excessive, as it led to a significantly thicker Laves phase and coarser grains. As a result, both the strength and elongation of the samples were affected negatively.

Strengthening and toughening of Ti–Nb films by adjusting internal stress

Strength (or hardness) and toughness, as two properties that are exclusive each other, have attracted much attention for decades. Traditionally, the development of engineered materials has been a compromise between hardness and toughness. In this study, the internal stress of the Ti85Nb15 film can be controlled by changing the substrate bias voltage of magnetron sputtering. When the residual compressive stress reaches 768 MPa, the initiation and propagation of cracks are greatly suppressed and the fracture toughness reaches 1.35 MPa m1/2. At the same time, the residual compressive stress causes the stress-induced martensitic transformation (β→α) to occur, and the strengthening effect of α phase compensates for the softening effect of grain growth, making the hardness value as high as 9.77 GPa. The film also has a high work recovery rate of indentation, about 61%, showing excellent superelasticity. Finally, we find ΔKIC∝Fσπa, which proves that the residual stress is the main mechanism in toughening. This work not only provides a systematic experimental study on the influence of residual compressive stress on the mechanical properties of the film, but also proves that it is a feasible way to achieve the strength and toughness of the film by adjusting the internal stress.

Effect of duplex aging on microstructural and mechanical behavior of a new β-Ti alloy for biomedical applications

The influence of duplex aging on the microstructural and mechanical behavior of Ti–25Nb–10Ta–1Zr-0.2Fe alloy was investigated. The first step of duplex aging (DA) treatments was carried out at 300 °C or 400 °C for 20min and 1 h, followed by the second step aged at 550 °C for 20min-24 h.A small amount of athermal ω (ωath) formed in the β matrix after solution treatment and water quenching. During single aging (SA) at 550 °C, upon slowly heating process, the ωath→isothermal ω (ωiso)→isothermal α" (α"iso) might occur. Subsequently, the α"iso dissolved rapidly and transformed into α phase at the early stage of aging, resulting in a fine distribution of α precipitates in the β matrix. During DA treatments, the fine ωiso and α"iso were observed in the first stage aging at 300 °C/400 °C, then the metastable ωiso and α"iso decomposed into α phase at higher temperature of 550 °C. Besides fine α laths, ladder-shaped α clusters with large size were observed after DA. There was a single-peak in the hardness curve of SA, and the peak hardness was associated with the uniform distribution of fine plate-like α phase. After DA treatments, the alloy showed stronger age-hardening and displayed obvious double-peak precipitation hardening. The first hardness peak was the result of the dense ωiso nano-particles formed in the first aging stage, while the second one could be mainly attributed to these large ladder-shaped α clusters in the second aging stage. Compared with SA, the balance between high strength and low modulus could be improved by an appropriate DA treatment.

Size effect on the martensitic transformation of Ti–Nb shape memory alloy

The effect of grain size on martensitic transformation was investigated by transmission electron microscopy in a nanocrystalline Ti–16Nb thin film with a broad range of grain sizes. The results show that the larger nanocrystals are filled with multiple variants with the {111}α" type I twinning relationship. As the grain size decreases to about 40 nm, the martensite changes to the single variant morphology, and the shape memory effect is believed to deteriorate significantly then. Finally, the martensitic transformation is totally suppressed and the β parent remains when the grain size drops below 25 nm.

Influence of the Ti Content on the Grain Stability and the Recrystallization Behavior of Nb‐Alloyed High‐Strength Low‐Alloyed Steels

To achieve higher strength and good hardenability and at the same time use the positive effects of thermomechanical controlled processing, the concept of Nb and Ti microalloyed steels is increasingly used for high‐strength low‐alloy (HSLA) steels with higher C contents. Herein, how the addition of Ti affects the grain growth and static recrystallization behavior of a Nb microalloyed HSLA steel with a C content of 0.23 wt% is investigated. For this reason, alloys with varying Ti and constant Nb content are produced and investigated by means of annealing and double‐hit deformation experiments. Atom probe tomography measurements reveal that the Nb concentration in the matrix decreases with increasing Ti content. Therefore, the static recrystallization behavior is steadily inhibited with decreasing Ti content, as more dissolved Nb is available for the formation of strain‐induced NbC precipitates. The annealing experiments show that the combined addition of Ti and Nb is most effective against grain coarsening, regardless of whether the Ti content is 90 or 180 ppm. To use the positive properties of Ti against grain coarsening and Nb to inhibit recrystallization, a middle content must be chosen when alloying Ti to HSLA steels with higher C content.

Deformation behavior and fracture mechanism of laminated Ti/Ti–50Nb composite fabricated by spark plasma sintering

The laminated Ti/Ti–50Nb composite (laminated Ti–Ti(Nb)) was designed and fabricated by spark plasma sintering (SPS) with alternately stacking pure Ti and Ti–50Nb sheets. The as-sintered composite exhibits a good combination of strength and ductility. Electron backscatter diffraction and digital image correlation was applied to study the grain orientation and strain evolution process during the tensile deformation. The layered structure could help relieve strain localization and the laminated Ti–Ti(Nb) has a total elongation equivalent to that of pure Ti. In the meanwhile, the tensile strength of the laminated Ti–Ti(Nb) and the stress-strain curves before necking can be analyzed by applying the rule of mixture. With the increase of strain, the microvoids initiated, grown and coalesced at the Ti/Ti(Nb) interface, and some of them further expanded into cracks which separated the laminated Ti–Ti(Nb) into several units with fewer layers.

A2-Type Granites from the Bastar Craton, South-Central India, and Their Implication in Archean-Paleoproterozoic Tectonics in Indian Peninsula

Abstract This communication reports novel geochemical and geochronological data of granite from the southeastern part of the Bastar Craton, Central India. The studied samples are leucocratic in appearance and composed of quartz, K-feldspar, plagioclase feldspar, and biotite in decreasing order of abundances. Apatite, sphene, and zircon occur as accessory minerals. The SiO2 and Al2O3 content of the studied sample varies between 61 and 69 wt.% and 13 and 15 wt.%, respectively. The alkali oxides, K2O, and Na2O content ranges between 3 and 6 wt.% and 2 and 3 wt. %, respectively. In the primitive mantle normalized spider diagram, the granites exhibit a negative Nb–Ti, Sr anomaly, and a positive Pb–Th anomaly. Similarly, in the REE normalized spider plot, the granites exhibit a strongly fractionated trend La/YbCN=10.90−28.4 with a negative Eu anomaly (0.42-0.70). The zircon saturation in silicate melt yields crystallization temperature (Tzr) ~650 to 800°C for the Eastern Bastar Craton rocks. The P-T pseudosection modeling implies EBC granites which are crystallized at 700-750°C, at 0.4 to 0.6 GPa. The SHRIMP U-Pb ages from magmatic zircon yield an upper intercept at ~2470 Ma and a lower intercept at ~2100 Ma. When combined with the results of P-T pseudosection modeling, the geochemical and geochronological data classifies the Eastern Bastar Craton rocks as A2 granites that were emplaced during the amalgamation of Archean blocks leading to extended Ur formation. The ~2100 Ma age is correlated with mafic dyke emplacement and the Bastar Craton–Yilgarn Craton block disintegration before Paleoproterozoic Columbia supercontinent assembly.

Mechanobiologically optimized Ti–35Nb–2Ta–3Zr improves load transduction and enhances bone remodeling in tilted dental implant therapy

The tilted implant with immediate function is increasingly used in clinical dental therapy for edentulous and partially edentulous patients with excessive bone resorption and the anatomic limitations in the alveolar ridge. However, peri-implant cervical bone loss can be caused by the stress shielding effect. Herein, inspired by the concept of “materiobiology”, the mechanical characteristics of materials were considered along with bone biology for tilted implant design. In this study, a novel Ti–35Nb–2Ta–3Zr alloy (TNTZ) implant with low elastic modulus, high strength and favorable biocompatibility was developed. Then the human alveolar bone environment was mimicked in goat and finite element (FE) models to investigate the mechanical property and the related peri-implant bone remodeling of TNTZ compared to commonly used Ti–6Al–4V (TC4) in tilted implantation under loading condition. Next, a layer-by-layer quantitative correlation of the FE and X-ray Microscopy (XRM) analysis suggested that the TNTZ implant present better mechanobiological characteristics including improved load transduction and increased bone area in the tilted implantation model compared to TC4 implant, especially in the upper 1/3 region of peri-implant bone that is “lower stress”. Finally, combining the static and dynamic parameters of bone, it was further verified that TNTZ enhanced bone remodeling in “lower stress” upper 1/3 region. This study demonstrates that TNTZ is a mechanobiological optimized tilted implant material that enhances load transduction and bone remodeling.

Exceptional improvement in the wear resistance of biomedical β-type titanium alloy with the use of a biocompatible multilayer Si/DLC nanocomposite coating

A silicon/diamond-like carbon (Si/DLC) multilayer nanocomposite coating (MNC) was applied to the Ti–29Nb–13Ta‒4.6Zr (TNTZ) alloy to improve its wear resistance and durability. The Si/DLC MNC on the TNTZ alloy demonstrated an extremely low wear rate of 6.2 × 10−10 mm3N−1mm−1. Moreover, the wear track depth after one million wear cycles was found to be only 220 nm, while the thickness of the entire coating was 370 nm. Furthermore, cell culture tests demonstrated that the Si/DLC MNC samples exhibited better biocompatibility than the TNTZ alloy samples. A quantitative comparison of the cell adhesion behavior of the TNTZ and Si/DLC MNC samples indicated that 60% of the surface of the Si/DLC MNC sample was covered with cells, which was approximately twice the surface of the TNTZ alloy sample covered with cells. In addition, no dead cells were observed on the Si/DLC MNC samples, indicating that the Si/DLC MNC samples exhibited no toxic effects against the MC3T3 cells. These results indicate that the Si/DLC MNC enhances the wear resistance of the TNTZ alloy and improves its biofunctionality, thus making it a potential candidate for use in long-term implant applications.

A Unique Nanoflake‐Shape Bimetallic Ti–Nb Oxide of Superior Catalytic Effect for Hydrogen Storage of MgH2

MgH2 is one of the most promising solid hydrogen storage materials due to its high capacity, excellent reversibility, and low cost. However, its operation temperature needs to be greatly reduced to realize its practical applications, especially in the highly desired fuel cell fields. This work synthesizes a 2D nanoflake-shape bimetallic Ti-Nb oxide of TiNb2 O7 , which has high surface area and shows superior catalytic effect for the hydrogen storage of MgH2 . Incorporated with the TiNb2 O7 nanoflakes as low as 3 wt%, MgH2 shows a low onset dehydrogenation temperature of 178 °C, which is lowered by 100 °C compared with the pristine one. A dehydrogenation capacity as high as 7.0 wt% H2 is achieved upon heating to 300 °C. The capacity retention is as high as 96% after 30 cycles. The mechanism of the improved hydrogen storage properties is analyzed by density functional theory (DFT) calculation and the microstructural evolution during dehydrogenation and hydrogenation. This work provides an MgH2 system with high available capacity and low operation temperature by a unique structural design of the catalyst. The high surface area feature of the TiNb2 O7 nanoflakes and the synthesis method hopefully can develop the application of TiNb2 O7 .

Circumventing the strength–ductility trade-off of β-type titanium alloys by defect engineering during laser powder bed fusion

In this study, we propose a novel defect engineering strategy for circumventing the strength–ductility trade-off of a β-type Ti–35Nb–7Zr–5Ta alloy and discuss its underlying mechanism. This strategy is based on the simultaneous introduction of dislocations and twins into the alloy structure through the thermal stress generated during additive manufacturing via laser powder bed fusion (LPBF). As a result, the LPBF-fabricated alloy contains high-density dislocations and two different types of nanosized {112}〈111〉 mechanical twins: unique zigzag-shaped and conventional lamellar ones. Interestingly, the produced alloy exhibits a high tensile yield strength of 816 MPa and large elongation of 16.5%, which significantly exceed the published values for other representative β-type titanium alloys fabricated by various material processing methods. Such a high yield strength is predominantly attributed to the introduced defects, and the relative contributions of dislocation strengthening and twin strengthening are equal to 58.0% and 26.1%, respectively. Meanwhile, the large elongation results from the inhibition effect of the produced twins on the dislocation motion as well as from their dislocation pass-through and growth. The obtained results can provide guidelines for the microstructural design and fabrication of novel β-type titanium alloys with excellent mechanical properties by defect engineering during additive manufacturing.

Laser Powder Bed Fusion Additive Manufacturing of a Low-Modulus Ti-35Nb-7Zr-5Ta Alloy for Orthopedic Applications.

Laser powder bed fusion (L-PBF) was attempted here to additively manufacture a new generation orthopedic β titanium alloy Ti–35Nb–7Zr–5Ta toward engineering patient-specific implants. Parts were fabricated using four different values of energy density (ED) input ranging from 46.6 to 54.8 J/mm3 through predefined laser beam parameters from prealloyed powders. All the conditions yielded parts of >98.5% of theoretical density. X-ray microcomputed tomography analyses of the fabricated parts revealed minimal imperfections with enhanced densification at a higher ED input. X-ray diffraction analysis indicated a marginally larger d-spacing and tensile residual stress at the highest ED input that is ascribed to the steeper temperature gradients. Cellular to columnar dendritic transformation was observed at the highest ED along with an increase in the size of the solidified features indicating the synergetic effects of the temperature gradient and solidification growth rate. Density measurements indicated ≈99.5% theoretical density achieved for an ED of 50.0 J/mm3. The maximum tensile strength of ≈660 MPa was obtained at an ED of 54.8 J/mm3 through the formation of the columnar dendritic substructure. High ductility ranging from 25 to 30% was observed in all the fabricated parts irrespective of ED. The assessment of cytocompatibility in vitro indicated good attachment and proliferation of osteoblasts on the fabricated samples that were similar to the cell response on commercially pure titanium, confirming the potential of the additively manufactured Ti–35Nb–7Zr–5Ta as a suitable material for biomedical applications. Taken together, these results demonstrate the feasibility of L-PBF of Ti–35Nb–7Zr–5Ta for potentially engineering patient-specific orthopedic implants.

The Role of Syn-Extensional Lamprophyre Magmatism in Crustal Dynamics—the Case of the Menderes Metamorphic Core Complex, Western Turkey

Abstract The Menderes Massif in Turkey represents one of the largest metamorphic core complexes in the world. It is regarded as a section of lower continental crust exhumed along low-angle detachment faults in the Late Miocene during a period of extension that affected the entire Aegean province. Syn-extensional magmatic activity within the Menderes metamorphic core complex is predominantly felsic forming several plutons, whereas mantle-derived magmatism has not been known so far. Here, we present a detailed study of the petrology and geochemistry of previously unreported mafic to intermediate lamprophyres within the Menderes Massif and assess their role in the geodynamic evolution of the core complex. The Menderes lamprophyres are mostly kersantites, with 49–60 wt % SiO2, 3.2–8.4 wt % MgO, 100–360 ppm Cr, 32–132 ppm Ni and Mg# of 37–50. Positive Pb and negative Ti–Nb–Ta anomalies suggest a clear orogenic affinity. Isotopes of Sr and Pb are relatively radiogenic (87Sr/86Sr = 0.70609–0.71076; 206Pb/204Pb = 18.88–19.03, 207Pb/204Pb > 15.71), while Nd is unradiogenic (εNd = −1.4 to −3.2). Most phenocrysts are sharply zoned with a primitive core (Mg# 77–85, up to 0.95 wt % Cr2O3 in clinopyroxene; Mg# 72–76 in amphibole) and a more evolved rim (Mg# 68–74, <0.25 wt % Cr2O3 in clinopyroxene; Mg# 69–71 in amphibole). Trace element ratios between different cores may vary significantly (e.g. Dy/Yb 2–5 in amphiboles), whereas rims show less variation but are more enriched than the cores. U–Pb dating of zircons provides an age of 15 Ma for the lamprophyres, coeval with the syn-extensional granite magmatism. The Hf isotopic composition of magmatic zircons is variably unradiogenic (176Hf/177Hf15Ma = 0.28248–0.28253, εHf15Ma = −8.6 to −10.5), while zircon xenocrysts with dominantly Cadomian and older ages show highly variable Hf isotopic signatures at the time of lamprophyre emplacement (εHf15Ma = −7.6 to −46.7). The orogenic geochemical signature of the lamprophyres’ parental melts is similar to nearby orogenic lavas from the West Anatolian Volcanic Province. Variation in bulk-rock εNd and in Dy/Yb ratios of phenocryst cores reflect moderate mantle heterogeneity. The chemical heterogeneity of phenocrysts and zircon εHf values implies intense hybridisation of proto-lamprophyre melts with felsic crustal melts, most probably derived from the melting of augen gneisses of the Menderes basement. We propose that fluid released from the lamprophyre primary melt had a decisive impact on crustal melting and the formation of granitic plutons within the Menderes core complex.

Stabilization and control of persistent current magnets using variable inductance

Ultra-stable, tunable magnetic fields are desirable for a wide range of applications in medical imaging, electron microscopy, quantum science, and atomic physics. Superconducting magnets operated in persistent current mode, with device current flowing in a closed superconducting loop disconnected from a power source, are a common approach for applications with the most stringent requirements on temporal field stability. We present a method for active control of this persistent current by means of dynamic inductance change within the superconducting circuit. For a first realization of this general technique, we consider a variable superconducting inductor placed in series with the main magnet. The inductor acts as a dynamic flux storage device capable of transferring flux to or from the main magnet through inductance change. This allows for fine and fast adjustments of the persistent current without the use of thermal switches that limit the speed and accuracy of many present-day methods. With first experiments employing this technique, we demonstrate stabilization of a 1.95 T Nb–Ti round lens for electron microscopy against decay resulting from residual losses in the superconducting circuit, and more generally show flexibility for precise control over the magnitude and waveform of the persistent current.

Microstructure, mechanical properties, and cytotoxicity of low Young’s modulus Ti–Nb–Fe–Sn alloys

Microstructure, mechanical properties, and cytotoxicity of low Young’s modulus Ti–Nb–Fe–Sn alloys