Ti In Mg Research Articles

Elemental Abundances of Moon Samples Based on Statistical Distributions of Analytical Data

The successful return of Chang’E-5 (CE5) samples urges the hot topic of the study of the Moon in geochemistry. The elemental data of the analyzed moon samples reported in the literature were collected to determine the elemental abundances in moon samples. Based on 2365 analytical records of moon samples from ten missions of Apollo, Luna, and CE5, elemental abundances of 11 major oxides including Cr2O3, 50 trace elements including Ti, P, Mn, Cr, and 15 rare earth elements (REEs) including Y are derived based on statistical distributions of normal, log-normal, and additive log-ratio transformation, respectively. According to the value of 13.5% CaO content, moon samples are classified into two types, as low-Ca and high-Ca samples, whose elemental abundances are also calculated respectively based on the methods used in the total moon samples. With respect to the mid-ocean ridge basalt (MORB) of the Earth, moon samples (including the Moon, low-Ca, and high-Ca samples) are rich in Cr, REEs, Th, U, Pb, Zr, Hf, Cs, Ba, W, and Be and poor in Na, V, Cu, and Zn in terms of their concentrations, and are enriched in Cr and depleted in Na, K, Rb, P, V, Cu, Zn in spider diagrams. The CE5 sample is a low-Ca type of moon sample and is clearly rich in Ti, Fe, Mn, P, Sc, REEs, Th, U, Nb, Ta, Zr, Hf, Sr, Ba, W, and Be and poor in Mg, Al, Cr, and Ni in terms of their concentrations relative to the moon or the low-Ca samples. If compared with the moon sample, the CE5 sample is also clearly rich in K, REE, and P.

The effect of Mg content and milling time on the solid solubility and microstructure of Ti–Mg alloys processed by mechanical milling

This research presents a high energy ball milling method for producing supersaturated solutions of the Ti100-xMgx (x = 10, 15, 20) composite powders containing a process control agent (PCA) under an argon atmosphere at an ambient temperature. The microstructure of the Ti–Mg solid solution during milling was analyzed by scanning electron microscope, and an X-Ray diffraction. A particle size analyzer was employed to investigate the average particle size at different milling times (12 h, 20 h, 32 h). After milling for 32 h of Ti100-xMgx (x = 10, 15, 20) composite powders, the solid solubility of the Mg in Ti reached about 0.5 wt.%, 1.14 wt.%, and 1.92 wt.%, respectively. It was found that the crystallite size of the milled powder decreased by increasing the milling time and reached the value of 4–11 nm after 32 h of milling. Moreover, the addition of the process control agent after 12 h and 20 h significantly reduced the agglomeration by cold welding. As a result, the average particle size of the dispersed composite powder Ti100-xMgx (x = 10, 15, 20) was refined to about 1 μm which indicated that the Ti controlled the final size as being a major alloying element. The maximum value of the density of green compacts was found to be 2.69 g/cm3 for Ti–10Mg.

Effects of Mg addition on the phase formation, morphology, and mechanical and tribological properties of Ti-Nb-Mg immiscible alloy coatings produced by magnetron co-sputtering

The addition of Mg to Ti-based alloys is a promising method for improving bioactivity in this type of alloys because Mg is absorbed by the body and can biologically activate the implant material, facilitating its adaptation. However, the fabrication of Ti-Nb-Mg alloys by conventional processes is extremely difficult due to the very low solubility of Mg in Ti and the very large difference in their melting points. Therefore, non-equilibrium processing methods such as magnetron sputtering can be used to produce metastable supersaturated Ti-Mg alloys with low density and attractive mechanical properties. In the present study, Ti85-xNb15Mgx (x = 5, 8, 16, 25 at.%) coatings were successfully produced by magnetron co-sputtering deposition on AISI 316L SS substrates. The effects of Mg content on the phase formation, morphology, and mechanical and tribological properties of the Ti-Nb-Mg coatings were investigated. The coatings with lower Mg contents (5 and 8 at.%) presented a predominance of the α (hexagonal close packed - HCP) phase (near α-Ti), the coating with 16 at.% Mg had near equal relative quantity of the α and the β phases (α + β type), and the coating with 25 at.% Mg had almost only the β phase (β-Ti type). A greater stabilization of the β-Ti phase with the increase of Mg content yielded a decrease in both the elastic modulus (102 to 88 GPa) and the hardness values (2.7 to 2.1 GPa). Tribological tests did not detect any detachment of the coatings, due to the high plastic joint strain of the coating/substrate systems, that ensures integrity and good adhesion. Failure was observed only on the coating and depended on α and β relative amounts in the coating.

Exothermically reactive titanium–silica nanoparticles

This paper focuses on developing Ti–SiOx nanoparticles and evaluating their self-propagating exothermic function. In combination with an atomized heating method, molten salt reduction, and sputtering, we established a fabrication technique for Ti–SiOx nanoparticles in which their exothermic characteristics can be designed. In the atomized heating method, porous SiOx nanoparticles with various spherical shapes, sizes, and porosities were fabricated. Porous SiOx nanoparticles with uniformly arranged pores were produced at a polystyrene latex (PSL) concentration of approximately 3.0 wt%. Reduction of the oxygen content of the porous SiOx nanoparticles was conducted using molten salt. Ti was deposited onto the entire surface by stirring and sputtering. The completed 1.0 mg of Ti–SiOx nanoparticle powder exhibited a self-propagating exothermic reaction by applying an electric spark. The relationship between PSL concentration and heat generation characteristics, such as the maximum temperature, time to reach maximum temperature, and duration of the exothermic reaction, was investigated.

Facilitation of quasi-reversible effect with rapid diffusion kinetics on Mg0.9-xTi0.1Nix high energy ball milled powders for Ni-MH batteries

In this research work, Mg-Ti-Ni alloys had been processed through mechanical alloying route. The X-ray diffraction profile of 30 h ball milled Mg0.875Ti0.1Ni0.025 and 20 h milled Mg0.825Ti0.1Ni0.075 powders reveal the partial solid solution of Ti in Mg with induced lattice defects. Especially the 15 h milled Mg0.875Ti0.1Ni0.025 and 30 h milled Mg0.85Ti0.1Ni0.05 powders reveal that their particles are uniformly and intimately mixed with better polydispersity (%) during milling. They consists of fine crystallites (i.e. 21–40 nm in size) with more incorporated micro-strain (i.e. 0.13–0.23%). The ultra violet visible spectra reveal that the band gap energies of Mg0.9-xTi0.1Nix powders have been increased with reduction in crystallite size, increased surface area, surface energy and structural defects. The 30 h milled Mg0.85Ti0.1Ni0.05 powder transmits 46.65% of photons with increased band gap energy of 1.263 eV. The tuned bandgap energy (i.e. 1.0 eV–1.3 eV) materials with photonic transmittance (i.e. approximately 40–60%) behaviour have been attributed to the quasi reversibility of hydrogen ions with rapid diffusion kinetics. The effect of quasi-reversible has been well perceived in the cyclic voltammogram and the cyclic discharge curve with high desorption specific capacity of 531 & 424 mAh g−1 respectively for the 30 h milled Mg0.85Ti0.1Ni0.05 powder. The electrochemical impedance spectrum has been revealed an exchange ion current density of 2380 mA g−1 and low polarization resistance 36 mΩ for the 30 h milled Mg0.85Ti0.1Ni0.05 powder. The poor internal impedance leads to poor polarization and enhances the quasi-reversible behaviour.

Geochemical characteristics of magnetite in Longqiao skarn iron deposit in the Middle-Lower Yangtze Metallogenic Belt, Eastern China

The Longqiao Fe deposit is the only large stratabound Fe skarn in Eastern China. This extensive ore body is suitable for investigating the spatial variations in trace elements in magnetite from the intrusion to the wall rocks and tracing the evolution of the mineralizing fluid in a skarn deposit. Magnetite samples were collected every 200 m from the ore-forming gabbro-diorite to the edge of the ore body, including the diopside-magnetite and epidote-chlorite-magnetite stages. Our results show that magnetite proximal to the gabbro-diorite displays lower Mg, Al, and Si and higher contents of Ti and V than those found further from the gabbro-diorite. The hydrothermal fluids in both diopside-magnetite and epidote-chlorite-magnetite stages were influenced by reaction with marine sedimentary rocks. Magnetites from different parts of the ore body display a wide range of trace element contents and fall into the porphyry and skarn fields on a (Mn + Al) vs. (Ti + V) discrimination diagram. Based on our results and published data, we propose that the early-stage magnetite from skarn and iron oxide-apatite (IOA) Fe deposits is compositionally similar, and fluid compositional variations are largely dependent on differences in the composition of the wall rock and the intensity of fluid-rock interactions. This results in a large variation in (Ti + V) in magnetite compositions from skarn deposits in the (Mn + Al) vs. (Ti + V) discrimination diagram, which is different from IOA deposits. This study shows that magnetite trace element evolution trends can provide a reliable indication to recognize skarn and IOA deposit types.

Attempts to understand potential deficiencies in chemical procedures for AMS: Cleaning and dissolving quartz for 10Be and 26Al analysis

The purity of the analysed samples (e.g. quartz) with respect to chemical composition and radionuclide contamination is essential for geomorphologic applications using so-called terrestrial cosmogenic nuclides (TCNs). To guarantee this, numerous cleaning and dissolution procedures have been developed. At the DREsden Accelerator Mass Spectrometry (DREAMS) facility, we also work on enhancing the chemical quartz-enrichment methodology from bulk rock and dissolution of quartz. Repeated exposure of the bulk material to acid mixtures (HCl/H2SiF6) at room temperature for cleaning and its monitoring by optical microscopy works for most quartz-rich samples. The quartz dissolution in HF under rather mild conditions (at room temperature on a shaker-table) has the advantage to leave difficult-to-dissolve minerals (e.g., tourmaline, zircon, rutile, sillimanite, kyanite, chromite, corundum), not separated by other physical methods before, as residue. Our comparison with a high-temperature dissolution method (in a microwave) indicates an additional amount of interfering elements, such as in average about 3 mg of Ti, more than 7 mg of Al, and about 22 μg of Be (for 50 g SiO2), is added to the sample, hence showing the superiority of our mild method. This way, we reduce problems for chemistry and AMS, but also ensure better comparability to production rates of cleaner stoichiometric quartz from calibration sites.

Genesis of Early Cretaceous porphyrite-type iron deposits and related sub-volcanic rocks in the Ningwu Volcanic Basin, Middle-Lower Yangtze Metallogenic Belt, Southeast China

ABSTRACTThe Ningwu Volcanic Basin (NVB), located in the Lower Yangtze Metallogenic Belt, is characterized by the widespread occurrence of porphyritic iron-ore deposits. These deposits are clustered in three areas within the basin: the northern, central, and southern districts. Our study shows that the differences are existed in geochemistry of the rocks and the mineralization of the deposits among these three districts. Though results of Sr–Nd isotopes indicate that the parental magma of the sub-volcanic rocks in NVB were derived from EMI and EMII, however, the sub-volcanic rocks from the northern and southern districts have higher εNd(t) values (t = 130 Ma) and lower initial 87Sr/86Sr ratios (t = 130 Ma) than those from middle district. The rocks from northern and southern districts are similar to EMI in geochemistry; in contrast, rocks from the middle district are close to EMII. Meanwhile, the deposits from different districts show some differences in mineralization. The magnetites from the northern ore deposits are rich in Cu, Mo, Zn, and Mg and poor in Ca, Al, and Ti, which probably indicates that the magnetites from the northern ore deposits closer to hydrothermal genesis than to magmatic genesis, but the magnetites from the centre are closer to both magmatic and hydrothermal geneses. Based on the fact that a part of the sub-volcanic rocks is closer to EMI and another part to EMII in geochemistry, we suggested that the incorporation of the lower and upper crustal materials into the source regions of the sub-volcanic rocks has taken place by different manner and processes. Integrated with analysis of the tectonic evolution of NVB, we come to the conclusion that the sub-volcanic rocks have recorded the geochemical imprints of the subduction of Yangtze block towards North China block during Indosinian Period and the delamination of the lower crust of Yangtze block during Yanshanian Period.

Nature of three episodes of Paleoproterozoic magmatism (2180 Ma, 2115 Ma and 1890 Ma) in the Liaoji belt, North China with implications for tectonic evolution

Three episodes of Paleoproterozoic magmatism with distinctively different nature in the Liaoji belt of the Eastern North China Craton are discussed here: the 2200–2140Ma Liaoji A-type granites, the 2160–2110Ma Haicheng mafic sills and the ∼1890Ma Qingchengzi I-type granites. The Mafeng monzogranitic pluton, representative of the Liaoji A-type granites, gives a SIMS U-Pb zircon age of 2181±6Ma (n=20, MSWD=4.3). The Qingchengzi plagiogranitic pluton, representative of the Qingchengzi I-type granites, gives a SIMS U-Pb zircon age of 1891±10Ma (n=8, MSWD=1.8). The Mafeng monzogranites are high in Fe, Ti, K but low in Mg, Al and Ca. They have high abundance of total REEs (ΣREE=213–346ppm). They are relatively depleted in feldspar-compatible elements (e.g., Eu and Sr) and HFSEs (e.g., Nb, Ta, P and Ti). They have high 10000×Ga/Al ratios of 3.19–3.61 and Zr+Nb+Ce+Y concentrations of 472–656ppm, which are typical for A-type granite. The Qingchengzi plagiogranites have relatively high Al, Ca, Na but low Fe, Ti and K contents. They have low abundance of total REEs (ΣREE=17.6–21.6ppm). They are enriched in LILEs (e.g., Ba, K and Sr) but depleted in HFSEs (e.g., Nb, Ta, P, Ti and Y). These features, combined with extremely high Sr/Y ratios (327–413), are comparable with those of typical modern adakites. The Liaoji A-type granites show a source same to that of the Haicheng mafic sills and they originated from the Archean subcontinental lithospheric mantle plus with contamination from the Archean granites. However, the Qingchengzi I-type granites are interpreted to originate from subducted oceanic crust with significant contributions from sediments. The Liaoji A-type granites and the coeval bimodal volcanism in the Liaohe Group as well as the Haicheng mafic sills may represent episodic magmatism which was related to a protracted intra-continental rifting caused by lithospheric extension. The ca. 1890Ma Qingchengzi I-type granites and coexisting S-type granites as well as the coeval regional metamorphism are favored to represent an active continental magmatism linked to Paleoproterozoic subduction.

Mantle metasomatism and magma formation in continental lithosphere: Data on xenoliths in alkali basalts from the Makhtesh Ramon, Negev desert, Israel

Mantle xenoliths (lherzolites, clinopyroxene dunites, wehrlites, and clinopyroxenites) in the Early Cretaceous volcanic rocks of Makhtesh Ramon (alkali olivine basalts, basanites, and nephelinites) represent metasomatized mantle, which served as a source of basaltic melts. The xenoliths bear signs of partial melting and previous metasomatic transformations. The latter include the replacement of orthopyroxene by clinopyroxene in the lherzolites and, respectively, the wide development of wehrlites and olivine clinopyoroxenites. Metasomatic alteration of the peridotites is accompanied by a sharp decrease in Mg, Cr, and Ni, and increase of Ti, Al, Ca contents and 3+Fe/2+Fe ratio, as well as the growth of trace V, Sc, Zr, Nb, and Y contents. The compositional features of the rocks such as the growth of 3+Fe/2+Fe and the wide development of Ti-magnetite in combination with the complete absence of sulfides indicate the high oxygen fugacity during metasomatism and the low sulfur concentration, which is a distinctive signature of fluid mode during formation of the Makhtesh Ramon alkali basaltic magma. Partial melting of peridotites and clinopyroxenites is accompanied by the formation of basanite or alkali basaltic melt. Clino- and orthopyroxenes are subjected to melting. The crystallization products of melt preserved in the mantle rock are localized in the interstices and consist mainly of fine-grained clinopyroxene, which together with Ti-magnetite, ilmenite, amphibole, rhenite, feldspar, and nepheline, is cemented by glass corresponding to quartz–orthopyroxene, olivine–orthopyroxene, quartz–feldspar, or nepheline–feldspar mixtures of the corresponding normative minerals. The mineral assemblages of xenoliths correspond to high temperatures. The high-Al and high-Ti clinopyroxene, calcium olivine, feldspar, and feldspathoids, amphibole, Ti-magnetite, and ilmenite are formed at 900–1000°. The study of melt and fluid inclusions in minerals from xenoliths indicate liquidus temperatures of 1200–1250°C, solidus temperatures of 1000–1100°C, and pressure of 5.9–9.5 kbar. Based on the amphibole–plagioclase barometer, amphibole and coexisting plagioclase were crystallized in clinopyroxenites at 6.5–7.0 kbar.

Major and Trace Elements of Magnetite from the Qimantag Metallogenic Belt: Insights into Evolution of Ore–forming Fluids

AbstractMagnetite, as a genetic indicator of ores, has been studied in various deposits in the world. In this paper, we present textural and compositional data of magnetite from the Qimantag metallogenic belt of the Kunlun Orogenic Belt in China, to provide a better understanding of the formation mechanism and genesis of the metallogenic belt and to shed light on analytical protocols for the in situ chemical analysis of magnetite. Magnetite samples from various occurrences, including the ore‐related granitoid pluton, mineralised endoskarn and vein–type iron ores hosted in marine carbonate intruded by the pluton, were examined using scanning electron microscopy and analysed for major and trace elements using electron microprobe and laser ablation–inductively coupled plasma–mass spectrometry. The field and microscope observation reveals that early–stage magnetite from the Hutouya and Kendekeke deposits occurs as massive or banded assemblages, whereas late–stage magnetite is disseminated or scattered in the ores. Early–stage magnetite contains high contents of Ti, V, Ga, Al and low in Mg and Mn. In contrast, late–stage magnetite is high in Mg, Mn and low in Ti, V, Ga, Al. Most magnetite grains from the Qimantag metallogenic belt deposits except the Kendekeke deposit plot in the “Skarn” field in the Ca+Al+Mn vs Ti+V diagram, far from typical magmatic Fe deposits such as the Damiao and Panzhihua deposits. According to the (MgO+MnO)–TiO2‐Al2O3 diagram, magnetite grains from the Kaerqueka and Galingge deposits and the No.7 ore body of the Hutouya deposit show typical characteristics of skarn magnetite, whereas magnetite grains from the Kendekeke deposit and the No.2 ore body of the Hutouya deposit show continuous elemental variation from magmatic type to skarn type. This compositional contrast indicates that chemical composition of magnetite is largely controlled by the compositions of magmatic fluids and host rocks of the ores that have reacted with the fluids. Moreover, a combination of petrography and magnetite geochemistry indicates that the formation of those ore deposits in the Qimantag metallogenic belt involved a magmatic–hydrothermal process.

Synthesis of nanocrystalline Mg-based Mg–Ti composite powders by mechanical milling

The method of mechanical milling was applied to synthesize nanocrystalline MgxTi100−x (x=95, 90, 85) composite powders. The results reveal that mechanical milling is an effective method for preparing Mg–Ti composite powders, which consist of nanocrystalline Mg matrix and fine dispersed Ti particles. Moreover, the microstructure evolution and morphology of the as-milled powders were observed, and the corresponding mechanisms were also discussed. After milling for 60h, the crystallite size of the matrix Mg in MgxTi100−x (x=95, 90, 85) composite powders was refined to 105nm, 84nm, and 76nm, respectively. Meanwhile, the average size of the dispersed Ti particles in MgxTi100−x (x=90) composite powders was refined to about 1μm. Based on the XRD data, the solid solubility of Ti in Mg was calculated by using the Vegard's law. For all these Mg–Ti composite powders, the solid solubility of Ti in Mg seemed to be closely related with the milling time and the content of Ti. In the 60h-milled MgxTi100−x (x=95, 90, 85) composite powders, the solid solubility of Ti in Mg was estimated to be 0.56at.%, 1.32at.% and 2.35at.%, respectively.

Geochemistry, Geochronology, Sr‐Nd Isotopic Compositions of Jiang Tso Ophiolite in the Middle Segment of the Bangong‐ Nujiang Suture Zone and Their Geological Significance

AbstractThe Jiang Tso ophiolite, situated in the middle segment of the Bangong‐ Nujiang Suture Zone, is a part of the easternmost Qieli Lake ophiolite subzone and is close to the south of Pung Lake ophiolite. The rock association of Jiang Tso ophiolite is relatively complete and is mainly composed of metamorphic peridotite, gabbro and diabase. Comparing with N‐MORB, the ophiolite is high in Mg and low in Ti, K, Na, P, and is depleted in Nb, Ta, Hf, Th and enriched in Rb, Sr and Ba. Geochemical characteristics of the Jiang Tso ophiolite indicate it is of a supra‐subduction zone type formed in the spreading ridge of back arc basin. The SHRIMP U‐Pb dating of zircons from the gabbro yielded a weighted average age of 188.1±4.1 Ma (MSWD=1.4), indicating the Jiang Tso ophiolite was formed in the late stage of early Jurassic. The Sr, Nd isotopic compositions show that the Tethyan mantle domain is the depleted mantle (DM), with enriched mantle domain II (EM II). They have the same Sr, Nd isotopic composition with the India Ocean MORB type.

Low volume fraction nano-titanium particulates for improving the mechanical response of pure magnesium

In the present study, new light weight Mg–Ti nanocomposites with superior mechanical properties compared to pure magnesium are synthesized using disintegrated melt deposition technique followed by hot extrusion. The microstructural characterization studies revealed that the samples exhibited fairly uniform distribution of titanium nano particulates with minimal porosity and good interfacial integrity between Mg matrix and Ti particulates. The CTE results revealed that the addition of (0.58, 0.97 and 1.98)vol.%Ti reinforcements marginally improve the dimensional stability of pure magnesium. The room temperature tensile properties of the synthesized nanocomposites revealed a significant increase in the 0.2%YS (∼79% to ∼112%) and UTS (∼ 46% to ∼81%) when compared to pure magnesium, with decrease in ductility. The presence of nano-sized 1.98vol.%Ti in pure Mg revealed the best tensile properties with an increase in 0.2%YS by ∼112% and UTS by ∼81%, while the ductility decreased by ∼49% but comparable to the other work reported on Mg–Ti microcomposites available in the literature. The room temperature compressive properties of the nanocomposites reveal that the addition of 0.97Ti increases the 0.2%CYS of Mg by ∼59% and with 0.58Ti, the UCS of Mg increased by ∼34% with an inappreciable decrease in the ductility.

Advanced study of hydrogen storage by substitutional doping of Mn and Ti in Mg2Ni phase

The substitutional doping of Mn and Ti in Mg2Ni phase has been investigated by first principles density functional theory calculations. The calculation of enthalpy of formation shows that among the four different lattice sites of Mg(6f), Mg(6i), Ni(3b) and Ni(3d) in Mg2Ni unit cell, the most preferable site of substitution of Mn in Mg2Ni lattice has been confirmed to be Mg(6i) lattice site. The most preferable site of Ti substitution in Mg2Ni lattice is Mg(6i) position and the stability of Ti-doped Mg2Ni decreases with the increase of substitution quantity of Ti for Mg.

Structure and properties of cast Al–Si based alloy with Zr–V–Ti additions and its evaluation of high temperature performance

A hypoeutectic Al–Si based alloy with Cu, Mg and additions of Zr, V and Ti, was evaluated to determine its suitability for applications at higher temperatures. The as-cast alloy consists of α-Al matrix, Al–Si eutectic and Al2Cu, Al5Mg9Si8Cu2 and Al14Mg4FeSi6/Al5FeSi, intermetallic phases, plus two distinct Zr–V–Ti-based phases. Solutionizing treatment leads to dissolution of Al5Mg8Si6Cu2 and Al2Cu and the partial dissolution of Zr–V–Ti-based intermetallics. Integration of aging kinetics with mechanical properties data allowed to establish different aging parameters leading to T6 peak-aging and T7 over-aging conditions corresponding to hardness of 96 and 68 HRF respectively. T7 condition enabled higher hardness retention than T6 condition; the alloy softening was observed at 260°C versus 240°C after T6 treatment. TEM characterization of the alloy in the T6 condition revealed GP zones, and rod-shaped trialuminide Al3(Zr, V, Ti) with average size of 230nm as well as S-phase (Al2CuMg) precipitates. After T6 treatment followed by isothermal annealing at 475°C, the alloy showed hardness retention improvement by approximately 30%. Subsequent TEM analysis revealed a higher density of the Al3(Zr, V, Ti) rod-shaped precipitates along with formation of new lath shaped Q′-phase AlSiCuMg precipitates. Two over-aging reactions between 250–350°C and 440–460°C were associated with the stability of Cu–Mg and Al-Zr–V–Ti based nanoprecipitates respectively. Temperature of 250°C was established as the transition temperature above which degradation of mechanical properties was observed from UTS of approximately 311MPa at room temperature to 208MPa at 250°C. The results indicate that additions of Zr, V and Ti improve yield strength and cyclic yield strength at room temperature but lower ductility, while slightly improve elevated temperature hardness with almost no effect on tensile strength.

Systematic geochemical study of the soils, litter, and bedrock of a Permian limestone mountain, Central Japan

The paper deals with the results of a systematic geochemical study of soils at Mt Kinshozan in Central Japan, a limestone area known for its well-preserved Permian fossils. Compared with the typical composition of the Japanese upper continental crust, here the soils were found depleted in Si, Ca, Na, Mg, and K and rich in Ti, Al, and Fe. They were enriched with some heavy metals (Cr, Ni, Cu, Pb, and Zn) detected also in the acetic-acid residue of the limestone collected from Mt. Kinshozan. Therefore, the residual materials produced through chemical weathering of the limestone bedrock may have significantly contributed to the soils formation. Concentrations of C<sub>total</sub> were nearly identical to C<sub>org</sub> and the relationship between C<sub>total</sub> and Element/TiO<sub>2</sub> suggested a significant contribution of the litter to Si, Mg, Ca, and P in the soils.

Consolidation of Blended Titanium/Magnesium Powders by Microwave Processing

Mg-Ti alloys are attractive for structural applications because of low density and improved corrosion resistance by selective oxidation including hydrogen storage and switchable mirror applications. Titanium has a melting point (1670°C) that greatly exceeds the boiling point of magnesium (1090°C) and therefore, alloying of Mg and Ti by conventional methods is extremely difficult. Secondly, the solubility of Ti in liquid Mg is very low and it is difficult to extend solubility by rapid solidification. Physical vapor deposition by electron beam deposition and magnetron co-sputtering has been used to extend the solubility of Ti in Mg. Mechanical alloying and anvil-cell processing at extreme temperatures and pressures have also used to enforce alloying of Mg with Ti. The present paper deals with the consolidation of blended magnesium-titanium powders by microwave heating, an approach that appears highly cost effective.

Relationships between Zr substitution for Ti and microwave dielectric properties in Mg(Zr xTi 1− x)O 3 ceramics

The influence of Zr substitution for Ti on the microwave dielectric properties and microstructures of the Mg(Zr x Ti 1− x )O 3(MZ x T) (0.01 ≤ x ≤ 0.3) ceramics was investigated. The quality factors of Mg(Zr x Ti 1− x )O 3 ceramics with x = 0.01–0.05 were improved because the solid solution of a small amount of Zr 4+ substitution in the B-site could increase density and grain size. An excess of Zr 4+ resulted in the formation of a great deal of secondary phase that declined the microwave dielectric properties of MZ x T ceramics. The temperature coefficient of resonant frequency ( τ f ) of Mg(Zr x Ti 1− x )O 3 ceramics slightly increased with increasing Zr content, and the variation in τ f was attributed to the formation of secondary phases.

DFT studies of hydrogen storage properties of Mg 0.75Ti 0.25

Absorption energies of hydrogen in Mg 0.75Ti 0.25 alloys as a function of the hydrogen concentration were calculated using Density Functional Theory. Four types of structures of alloys and their hydrides including TiAl 3, ZrAl 3, AuCu 3, and segregated types of structures were considered. The stability of the configurations, and the structural and electronic bonding properties were studied. The hydrogenation properties depend highly on the structure of the alloys. The ordered alloys have very similar properties to that of pure Mg. For segregated alloys, the hydrogenation properties can be divided to Ti-like, ordered alloy-like and Mg-like from low to high hydrogen concentration. The formation energies show that for the four structures, segregated Mg 0.75Ti 0.25 is favored for alloys, whereas TiAl 3 type of Mg 0.75Ti 0.25H 2 are favored for hydrides. Therefore hydrogen induced structural rearrangement of the intermetallic structures of the Mg 0.75Ti 0.25 might occur upon hydrogen cycling. For the non-homogenous Mg–Ti–H system, further phase segregation of Ti in Mg might occur. Partial dehydrogenation with some hydrogen remaining in the Ti-rich region may improve reversibility.