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Excellent comprehensive mechanical properties and corrosion resistance of TiZrNb equiatomic ratio medium-entropy alloy were obtained through recrystallization and spinodal decomposition. In addition to solid solution strengthening and recrystallization, the excellent mechanical properties can also be attributed to the hindering effect of nanoprecipitation formed via spinodal decomposition on the movement of dislocations. The high atomic arrangement density due to spinodal decomposition reduces the surface energy of the alloy passivation film, thereby increasing the activation energy of dissolution and the bonding energy between atoms, which improve the corrosion resistance and stability of the alloy passivation film. This work provides a new strategy to control the mechanical properties and corrosion resistance by combining recrystallization and spinodal decomposition.

In this study, the vacuum tribological behaviors of the two TiZr-based alloys were investigated. The results show that the coefficient of friction of Ti-47Zr-5Al-3V alloy (T47Z)/ steel counterpart was lower at 0.59 m/s, while that of Ti-20Zr-6.5Al-4V alloy (T20Z)/ steel counterpart was lower when the sliding velocity was increased to 1.17 m/s. The wear volume of T47Z alloy was higher regardless of the tribological conditions. Zirconium content, normal load and sliding velocity were evaluated based on wear volume using the Taguchi method and ANOVA analysis, and they contributed 18.11, 53.79, and 14.44%, respectively. SEM was used to analyze the worn surface morphology. For T20Z alloy, the wear mechanisms varied from mild abrasive wear to delamination wear. However, the dominant wear mechanisms of T47Z alloy changed from mild abrasive wear and plastic flow to severe delamination wear and fatigue wear. The microstructural evolution of TiZr-based alloys was determined using TEM. At lower tribological parameters, the dislocation density of both alloys increased compared with unworn specimens. Under 30 N, 1.17 m/s condition, the SAED results show that only the β-phase was elongated in T20Z alloy. In contrast, subgrains, even nanograins, were formed in T47Z alloy under the same condition.

In this study, Zr41.2Ti13.8Cu12.5Ni10Be22.5 amorphous alloys samples with the same diameter (8 mm) were prepared by using self-designed molds (viz. refractory steel, pure graphite, and copper molds) with different cooling capacities. Moreover, by eliminating the size effect, the effect of the cooling rate on the microstructure and compression deformation behavior of Zr41.2Ti13.8Cu12.5Ni10Be22.5 amorphous alloys was investigated. Differentiation of the cooling curves revealed that the instantaneous cooling rates of the alloy melt at the glass transition temperature (Tg) are 45, 52, and 64 K·s―1 for refractory steel, pure graphite, and copper molds, respectively. X-ray diffraction, differential scanning calorimetry, and high-resolution transmission electron microscopy analysis revealed that with the decrease in the cooling rate, trace icosahedral-like atomic clusters and nanocrystals appear in local areas of the amorphous alloy and that the amount of free volume decreases with the increase in the amount of icosahedra-like atomic clusters and nanocrystals. Compression test results revealed that the elastic strain, yield strength, and compressive strength of the amorphous alloy marginally change with the decrease in the cooling rate, while the plastic strain gradually increases. By fitting, the effective size of the vein-like pattern was linearly related to the enthalpy released during structural relaxation and plastic strain, indicating that at a low cooling rate, the trace nanocrystals in the amorphous alloy could not effectively improve its plasticity and that the amount of free volume mainly affects its plasticity.

In order to expand the application horizon of Ti-Zr based alloys, the influence of Nb content on phase composition, microstructural evolution and biomechanical properties is systematically studied. The phase and microstructural characterization of the as-cast alloys is carried out by X-ray diffraction, optical microscopy and transmission electron microscopy. The results reveal that Nb-containing Ti-Zr alloys transformed from single α phase → α + α″ + β phase → single β phase → double β phases with increasing Nb content. In the case of β-type alloys, the addition of Nb improves the bonding energy between atoms, reduces the grain size, increases the elastic modulus, improves the yield strength and renders superior work-hardening behavior. Moreover, the current study provides mechanistic insights into microstructural evolution and strengthening of Nb-containing Ti-Zr alloys with increasing Nb content. Herein, the addition of 5 at.% Nb resulted in an abnormal work hardening during compression deformation under the synergistic influence of stress-induced martensite transformation of β phase and stress-induced twinning of α phase. Moreover, the biomechanical properties are evaluated to demonstrate the potential of Nb-containing Ti-Zr alloys in biological applications.

Many amorphous alloys have been developed to date, but the low plasticity has limited their application. To achieve an amorphous alloy with high plasticity, a series of (Ti40Zr25Cu9Ni8Be18)100−xTMx (x=0, 1, 2, 3, 4 at.%, TM=Nb, Y) alloys were designed to study the influence of Nb and Y addition on the plasticity. The amorphous samples were prepared using the vacuum melting and copper mold casting process. The microstructures, glass forming ability and mechanical properties of the alloys were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), depth-sensitive nanoindentation, and uniaxial compressive test. The plasticity of different bulk amorphous alloys was investigated by measuring the plastic deformation energy (PDE) during loading. The relationship between the PDE value and plasticity in bulk amorphous alloys was explored. Results show that Nb addition decreases the PDE value and promotes the generation of multiple shear bands, which significantly increases the fracture strength and plasticity, while the addition of Y element reduces the fracture strength and plastic strain of the alloy.

The taxonomy and phylogeny of four trachelocercid ciliates, Apotrachelocerca orientalis sp. nov., Tracheloraphis apoligostriata sp. nov., T. oligostriata and T. prenanti, isolated from marine habitats in Qingdao, China, were studied. The new species, A. orientalis sp. nov., can be distinguished from its most closely related congener, A. arenicola, by the absence of cortical granules and its conspicuously different SSU rDNA sequence. Tracheloraphis apoligostriata sp. nov. differs from the similar T. oligostriata by its body shape, distribution pattern of the cortical granules and SSU rDNA sequence. Based on available data, we suggest that T. prenanti can be defined by its colourless, globular cortical granules, which indicates that this species should be removed from the T. phoenicopterus-complex. Phylogenetic analyses based on SSU rDNA sequence data indicates that: A. orientalis sp. nov. groups with A. arenicola with full support, together sister to all other trachelocercid species; and T. cf. phoenicopterus, T. prenanti, T. oligostriata and T. apoligostriata sp. nov. form a clearly outlined clade.

Impurity segregation even small amounts, can drastically change the cohesive properties of the grain boundaries (GB), eventually leading to intergranular embrittlement and failure of the materials, thereby effectively controlling the types and the concentrations of the impurity is very important. In this work, the nonmetallic impurities (C, H, O, N) segregation and their effects on the strength of Zr (10 1 ¯ 2) GB were thoroughly investigated using first-principles calculations based on density functional theory. A comprehensive analysis of the interstitial configurations and the relative site energies indicating that C, N and O overwhelmingly prefer the octahedral sites, only H, prefers to reside in the tetrahedral sites. Moreover, the strengthening/embrittlement potency of impurity atoms on the GB was estimated using both the Rice-Wang model and first-principles tensile test calculations. The results show that all impurities, exhibit a strong segregation tendency near the GB region. The segregation of C, N and O has a remarkable strengthening effect on strength of the GB, whereas the presence of impurity H weaken the GB. Most importantly, the underlying mechanism of the strength change of the GBs due to the segregation of impurities was profoundly discussed by charge density and the bond lengths analyses, revealing that the strengthening effect especially for C-doped GB, mainly comes from an enhancement of the charge density across the GB plane. In the end, we expect that our results will be certainly useful for future theoretical and experimental investigations on Zr and its alloys.

Silkworm diseases caused by fungi infection occur frequently in sericulture and brought huge economic loss to sericulture. However, on the other hand, some fungi such as Beauveria bassiana, as an important entomological fungus, play an important role in biological control of insect pests. Here, two fungal pathogens causing yellow muscardine were isolated from the silkworm and named as SZY1 and SZY2. These two strains showed almost the same conidial morphology which were smooth, near-spherical, spherical, or ovoid and 2.7 ± 0.6 µm × 2.5 ± 0.9 µm in size, and the hyphal growth rate was also similar. However, the conidia production of SZY2 was almost twice as many as that of SZY1. The complete ribosomal RNA gene was sequenced and analyzed. As a result, the gene sequences of internal transcript space 1 (ITS1)-5.8S rRNA-internal transcript space 2 (ITS2) of SZY1 and SZY2 were identical in sequence and size, and for 18S rRNA, 28S rRNA, and intergenic spacer (IGS), the gene identity of SZY1 to SZY2 was 99%, 99%, and 98%, respectively. Results of phylogenetic analysis based on either ITS1-5.8S rRNA-ITS2 or 18S rRNA showed that both SZY1 and SZY2 were closely related to Beauveria bassiana. These results revealed that the pathogens of yellow muscardine SZY1 and SZY2 were identified as two different strains of Beauveria bassiana, which could provide diagnostic evidence for silkworm muscardine and was helpful for the research and development of novel Bombyx batryticatus and fungal biological insecticide.

In this study, unlubricated sliding friction and wear properties of a recently-developed TiZr-based alloy (Ti–20Zr–6.5Al–4V, TZ20 hereafter) were tested at elevated temperatures ranging from room temperature to 673 K. After the tribological tests, worn surface and cross-section of TZ20 alloy were analyzed to illustrate its wear behavior. The results showed that the wear rate was increased firstly with the ambient temperature, which then decreased when the temperature exceeded critical transition temperature (473 K). Also, the dominant wear mechanisms changed from adhesive wear at room temperature to abrasive wear at 473 K, and then to mild abrasive wear at highest ambient temperature of 673 K. The variations of wear behaviors could be attributed to tribo-oxide layer formed during sliding process. At ambient temperature of 673 K, the tribo-oxide layer formed on the surface was thicker and more compact, and showed more obvious protective role on tribological properties of TZ20 alloy.

Highly sinterable Yb:Lu2O3 nano-powders without hard agglomeration were synthesized via a highly efficient spray co-precipitation method. The effects of the spray speeds on morphology and composition of the powders were investigated. The results showed that the composition and dispersion of precursor powders changed with the spray speed. When the spray speed reached 40 mL/min, the particles were spherical and showed higher uniformity. The pure phase Yb:Lu2O3 powder was obtained after calcining at 1000 °C for 2 h. The calcined powders were ball milled and dry-formed to prepare green body. Then the Yb:Lu2O3 transparent ceramic was fabricated by vacuum sintering at 1500 °C for 8 h and further hot isostatic pressing in an argon atmosphere.. The in-line optical transmittance of Yb:Lu2O3 transparent ceramic reached 82.05%@1000 nm and 81.08%@400 nm, respectively, and it had submicron level average grain size, which is an effective way to improve the optical properties of the transparent ceramic.

A series of Ni-free Zr55Ti3HfxCu32-xAl10 (x = 0, 1, 2, 3, 4, 5 at. %) bulk metallic glasses (BMGs) were developed by copper mold suction-casting. The effect of partially substituting Cu by Hf was investigated in terms of glass-forming ability (GFA), mechanical properties, and corrosion behavior. As a result of the partial substitution, the GFA of Hf-bearing amorphous alloys were significantly enhanced as compared to Zr55Ti3Cu32Al10 BMGs. Hf addition also enlarged the supercooled liquid region from 55 K to 70 K. The critical diameter was found to increase from 4 mm to 8 mm for x = 3. The corresponding compressive yield strength was over 1800 ± 21 MPa with a large plastic strain above 2.60 ± 0.10%. Electrochemical tests indicated that the lowest corrosion current density was 1.6 ± 0.1 × 10−8 A/cm2 for the alloy with x = 5 in H2SO4 solution, thereby yielding a superior corrosion resistance.

Ampullofolliculina Hadži, 1951 is a monotypic genus, the only species being A. lageniformis which was first discovered in estuarine habitats in the U.S. and has never been redescribed. In the present study, we investigated the taxonomy and phylogeny of A. lageniformis Hadži, 1951 based on analyses of a population collected from a brackish wetland in Ningbo, China. The main characteristics of this species are as follows: trophont about 450-700 μm long in vivo with two short, rounded peristomial lobes of equal size; lorica flask-shaped, transparent and smooth with a short, wide neck at the base of which two transparent valves are asymmetrically inserted; cortex with brownish to reddish cortical granules and greenish pigment granules; about 80 somatic kineties evenly arranged; moniliform macronucleus with 4-8 ellipsoidal nodules; swarmer dark green, vermiform in shape, about 200-350 μm long in vivo, with about 60 adoral membranelles and 85 somatic kineties, no mouth nor paroral membrane. Phylogenetic analyses inferred from SSU rDNA sequences show that A. lageniformis is closely related to Folliculina and Eufolliculina which nest within a large clade that comprises five families, i.e. Stentoridae, Blepharismidae, Fabreidae, Maristentoridae, and Folliculinidae.

In this study, dry sliding tribological properties of a TiZr-based alloy with the chemical composition Ti-20Zr-6.5Al-4V (wt.%) were tested in air and vacuum under different normal loads (10, 20, and 30 N) at various sliding velocities. Results showed that the coefficient of friction in air was lower than that in vacuum, whereas the wear volume at sliding velocity presented an opposite trend. The surfaces and cross-sectional morphology of wear scar on the TiZrAlV alloy was analyzed through scanning electron microscopy to determine the wear mechanisms. The observations showed that abrasive wear and delamination wear were dominant in air. In vacuum, the main wear mechanism changed from slightly abrasive and adhesive wear to severe adhesive wear and delamination wear as the normal load increased. Wear mechanism maps were also constructed and compared. The comparison showed that severe wear (including delamination wear) was prevalent in air.

Corrosion behavior of the in-situ Ti-based bulk metallic glass matrix composites (BMGMCs) with a nominal composition of Ti42.3Zr29.1Cu6.6Nb6Be16 was studied in HCl and H2SO4 solutions with different concentrations. Potentiodynamic polarization tests indicated that at the lower solution concentration the corrosion current densities barely changed and their values were in the 10−7 - 10−8order of magnitude. However, corrosion current densities increased as the acid concentrations increased. Additionally, stable passivation films formed in the chloride-free solutions after polarization, but passive film breakdown and pitting corrosion were observed in HCl solution. Furthermore, the selective dissolution occurred in the amorphous matrix. Protective oxide films were enriched with Ti, Zr, and Nb oxides according to the XPS analysis after polarization on the surface. For a comprehensively study on the corrosion resistance of the BMGMCs, there also compared corrosion behavior of the composites with 316 stainless steel, Ti-6Al-4V and Zr-45Ti-5Al-3V alloys. It presents us a new reference value on the application of amorphous composites in their functioning environments.

Even small amounts of oxygen can profoundly affect the mechanical behavior of α-Zr, thereby controlling the oxygen concentration of Zr-O system plays a crucial role in its industrial application. In this work, we first conclude the oxygen solubility of α-Zr lying in the range of 33–38 at.%. Then, the mechanical and dynamical stability for all Zr-O compounds are confirmed by the analysis of elastic modulus and phonon dispersion. Furthermore, the stress responses of Zr-O system under the tensile and shear loadings have been systematically investigated by using first-principles calculations. The results reveal that ideal-strength depends on the O concentration strongly. Oxygen addition significantly enhances the ideal-strength compared with pure α-Zr, which provides direct evidence that α-Zr can notably harden by oxygen. Specifically, the alloy with 33 at.% oxygen contents exhibits the highest tension strength whereas 38 at.% oxygen content confers the alloy relatively excellent shear strength. Finally, the stress response and bonding nature of Zr-O system under loading are examined by the electronic structures.

The effect of Nb content on the corrosion behavior of in-situ (Ti0.45Zr0.31Be0.17Cu0.07)100−xNbx (x = 4, 6, 8, 10, and 12) was evaluated in 0.5 mol/L H2SO4, 0.6 mol/L NaCl, and 1 mol/L NaOH solutions. A dual-phase microstructure which composed of an amorphous matrix and dendrites was observed. Electrochemical measurements in each corrosion medium showed the same trend. The corrosion resistance first increased and then decreased with the addition of Nb content from 4 to 12 at.%. The results show the best corrosion resistance in terms of × = 8 for the alloys. Notably, Nb addition improved the pitting-corrosion resistance of samples in a chloride-containing solution, whereas spontaneous passivation occurred in chloride-free solutions. A preferential solution was observed in the amorphous matrix region in NaCl solution, but a part of dark spots and dents appeared on the surface after the polarization in chloride-free solutions. X-ray photoelectron spectroscopic measurements showed that Nb addition promoted the formation of metal oxide on the surface film, thus inducing a superior corrosion resistance for the bulk metallic glass matrix composites.

In this work, the effects of Ag substitution for Ti in Zr56Cu24Al9Ni7Ti4-xAgx (x = 0, 1, 2, 3, and 4 at%) bulk metallic glasses (BMGs) on the glass-forming ability, thermal stability and mechanical properties are investigated. The present research shows that the critical diameter increases to 6–8 mm for Ag content of x = 2 and 3 at%. Additionally, with increasing in the content of Ag, with a rod diameter of 3 mm, the glass-forming ability and thermal stability were effectively improved. The largest ultimate fracture strength and plastic strain were observed for alloys where x = 2 with a rod diameter in 3 mm (1863 (± 25) MPa and 7.9 (±0.6) %, respectively). Different fracture modes were observed using scan electron microscopy after compressive testing. This work illustrates that Ag can play an important role in improving glass-forming ability, thermal stability and mechanical properties for amorphous alloys.

The class Karyorelictea, a unique assemblage of ciliates, is a key group in deciphering ciliate evolution history. However, the systematic relationships among members of this class remain poorly understood. Here we newly obtained eight small subunit (SSU) rDNA, 24 large subunit (LSU) rDNA, and 25 ITS1-5.8S-ITS2 sequences (covering 25 species, 10 genera and 4 out of 6 families) to analyze the phylogenetic relationships within Karyorelictea. Our results indicate that: (1) considering its unique morphology and early branching position in the SSU rDNA-based tree, the family Wilbertomorphidae represents a new taxon at order level, hence the new order Wilbertomorphida n. ord. is established; (2) all five families with available molecular information are monophyletic, as expected, and the orders Loxodida and Protostomatida show a closer relationship than with Protoheterotrichida; (3) in Trachelocercidae, the compound circumoral kineties is believed to be a plesiomorphic feature while the single circumoral kinety is synapomorphic; and (4) the freshwater genus Loxodes could be derived from the marine Remanella and both share most morphological features. Taken together, these muti-gene analyses provide further insights into the phylogeny of the diverse clades in Karyorelictea.

The morphology of four trachelocercid ciliates, Paratrachelocerca typica gen. nov., spec. nov., Trachelolophos monocaryon (Dragesco, 1965) comb. nov. (original combination: Tracheloraphis monocaryonDragesco, 1965), Tracheloraphis katzae spec. nov., and Tracheloraphis colubis (Kahl, 1933) Xu et al., 2011 were studied in live and protargol-stained specimens. All samples were isolated from the intertidal zone of sandy beaches at Qingdao, China. The new genus Paratrachelocerca can be distinguished from other trachelocercid genera mainly by the three circumoral kineties each composed of a row of dikinetids and the absence of a brosse or ciliary tuft in the oral cavity. The detailed investigation on the poorly described Tracheloraphis monocaryon (Dragesco, 1965) reveals that its oral infraciliature includes one uninterrupted circumoral kinety and a conspicuous ciliary tuft in the center of the oral cavity, which is consistent with the genus Trachelolophos rather than Tracheloraphis. Therefore, this species is transferred to Trachelolophos as Trachelolophos monocaryon (Dragesco, 1965) comb. nov. Tracheloraphis katzae spec. nov. can be recognized by the combination of its minute brownish cortical granules and 9–15 somatic kineties. The small subunit (SSU) rDNA of each species was sequenced for the first time. Phylogenetic analyses of the SSU rDNA show that Paratrachelocerca typica gen. nov., spec. nov. clusters with Apotrachelocerca arenicola (Kahl, 1933) Xu et al., 2011 in a group that is sister to all other trachelocercids.