In this study, Sr-incorporated nano-assembled hydroxyapatite structures (HASr) on 316L stainless steel bone plates were prepared by a biomimetic method induced by 10× simulated body fluid (SBF). First, HASr was coated on bone plates by the interaction of ions with 10× SBF containing different concentration of strontium ions. Then, silver coating is achieved as a second layer on bone plates. The cumulative release of strontium ions (Sr2+) and silver ions (Ag+) from multilayered HASr-Ag bone plates at the end of 15 days was in the range of 0.016–0.085 mM and 0.064–0.135 mM, respectively. The release mechanism for the bone plates was evaluated by several mathematical models that best fit the release data. The results showed that Sr2+ and Ag+ are released from multilayered bone plates by diffusion, whereas the release of Ag+ is not occurred by diffusion, instead the mechanism is dissolution, when silver is coated alone on bone plates.

In this study, a three-phased multiwalled scaffold, composed of carbon nanotube (mwCNT), nanocrystalline hydroxyapatite (nHA), and polycaprolactone (PCL), was fabricated by the solvent evaporation technique. The structure character, mechanical properties, and degradation activity in simulated body fluid (SBF), along with osteoproductive ability in human osteosarcoma cell MG63, were investigated thoroughly. Results showed that the three phases in mwCNT/nHA/PCL composite presented excellent miscibility and stronger interfacial force when the weight content was 1/15/84 (wt%). Simultaneously, the composite had smaller porosity and slower degradation rate, and there was massive crystallized hydroxyapatite formed on the surface after being soaked in SBF. With regard to bioactivity, MG63s on this scaffolds presented good proliferation performance and differentiated into the osteogenic lineage by expressing high levels of ALP. It was concluded that mwCNTs/nHA/PCL composite scaffolds might be beneficial for bone tissue engineering at a relatively low concentration of mwCNTs and nHA.

Nanocrystalline (NC) and ultrafine-grained (UFG) CoCrCuFeNi high-entropy alloy (HEA) with grain size ranging between 59 and 386 nm was produced via powder metallurgy and heat treatment. The as-sintered HEA exhibited two face-centered cubic (FCC) phases (CoCrFeNi-rich and Cu-rich phases) and a small grain size (59 nm), whereas the alloy after heat treatment at 1000 °C exhibited a CoCuFeNi-rich phase with FCC structure and relatively larger grain size (386 nm). Moreover, the yield strength decreased from 1930 to 883 MPa, and plastic strain to failure increased by 8–32%. In terms of microstructural evolution, grain boundary strengthening coupled with lattice distortion was the dominant strengthening mechanism for NC HEAs. Furthermore, the coefficient for boundary strengthening was higher in the HEAs than in the corresponding pure elemental metals with FCC structure, possibly because of significant lattice distortion. The UFG HEAs exhibited high strength and good ductility because of the activation of dislocation.

Regular WO3 nanocubes have been prepared on a large scale through a convenient hydrothermal route at the temperature of 200 °C. The products were characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy, UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. A crystal growth process for WO3 nanocubes was simply proposed based on the comparative experiments. The band gap energy (Eg) was determined to be 2.58 eV based on the UV-vis DRS analysis, and the PL spectrum exhibited a strong blue light emission band centered at 469 nm. The as-prepared WO3 nanocubes showed higher visible light photocatalytic performance for degrading rhodamine B compared with WO3·H2O and WO3·0.33H2O/WO3 which were obtained at 80 °C and 140 °C, respectively, suggesting potential application in the region of wastewater purification.

A high-temperature nanoindentation system was used to examine the steady state indentation creep behavior of CsHSO4. This high proton conductivity solid-acid material is a candidate for use as a solid-state electrolyte in intermediate temperature fuel cells. Constant strain rate indentation creep tests yielded a stress exponent and a creep activation energy in close agreement with results obtained from previous uniaxial compression testing. The large penetration depths reached during creep testing necessitated validating an indenter area function well beyond depths measurable in fused silica. The developed methodology is material agnostic meaning it can be used for indentation creep measurements in other high creep rate materials. In addition, it is shown how an analysis developed by Bower et al. (Proc. Royal Soc. 441, 97–124, 1993) can be successfully used to convert the indentation creep parameters into the more common material parameters measured in uniaxial creep tests.

Discs of CoCuFeMnNi face centered cubic high entropy alloy were subjected to monotonic and cyclic high pressure torsion (HPT) in a single step and multiple steps of 5° forward and reverse cycle for 100° and 360° twist, respectively, under 5 GPa pressure at room temperature. It was observed that the 100° cyclic HPT sample shows the highest hardness at the periphery comparable to 360° monotonic HPT sample, while the cyclic 360° HPT sample shows the lowest hardness throughout the sample. High hardness of 100° cyclic HPT sample can be attributed to finer grain size and unstable dislocation substructure by continuous change in strain path from initial compression to forward–reverse torsion, while stable dislocation structure corresponding to shear contributes to increase in hardness from 100° to 360° for monotonic HPT sample. The unstable dislocation substructure promotes grain boundary migration–enabled grain growth leading to low hardness throughout the 360° cyclic HPT sample.

The activated carbon paper (ACP) has been designed as the active electrode material of supercapacitor to improve its capacitive performance. ACP is prepared by electrochemical nitrate ion–assisted exfoliation, sulfate ion–assisted exfoliation, and subsequent hydrothermal reduction processes. The as-prepared ACP shows obviously rougher surface along with the expanded layer distance. ACP exhibits higher specific capacitance of 380 mF/cm2 at 1 mA/cm2 than that of 21 mF/cm2 for carbon paper. ACP electrode shows the cycling capacitance retention of 98% after 5000 cycles at 10 mA/cm2. The symmetric ACP supercapacitor is constructed using ACP electrode and H2SO4 involved polyvinyl alcohol gel electrolyte. ACP supercapacitor presents the specific capacitance of 97 mF/cm2, the energy density of 0.343 mW h/cm3, and the output voltage of 1.6 V at 1 mA/cm2. ACP with high capacitance performance presents the promising supercapacitor application for the electrochemical energy storage.

This study investigated the compressive response of ice-templated composites and provides an understanding of their mechanical behavior based on the properties of templated ceramic and epoxy. Results suggested a dependence of properties on the microstructure of the templated porous ceramic, whereas more interestingly composites exhibited catastrophic and progressive types of failure. Compressive strength was found to be markedly greater relative to the strength of templated ceramic and polymer, and irrespective of the failure type, strength was greatly enhanced under dynamic loading relative to quasistatic loading. Compressive strength was also calculated based on the rule of mixtures and mode of failure in ice-templated ceramic. The analysis suggested that the axial mode of failure was not dominant in composites, and failures resulted from the fracture of lamella walls, possibly due to elastic instability. Fragments of the composite specimens were analyzed using scanning electron microscopy to study the fracture characteristics and rationalize the catastrophic and progressive types of failure.

Bioactive glass–ceramic powder reinforced alginate scaffold has been successfully prepared and characterized for bone tissue engineering application. Glass-ceramic (GC) particles were synthesized through a sol–gel process. Alginate scaffolds containing different weight percentages of GC were fabricated through a freeze-drying technique. The composite scaffolds were characterized for phase analysis through X-ray powder diffraction and microstructure analysis through field emission scanning electron microscopy. The swelling behavior, degradation behavior, bioactivity, cell adhesion, and osteogenic potential of the fabricated scaffolds were evaluated. Microstructural analysis showed a highly porous behavior of the scaffold having a macroporous pore size. The composite scaffolds showed good bioactivity where GC induces apatite formation. The compressive strength of the scaffold was enhanced with GC addition due to the reinforcement of the alginate matrix. In vitro cell studies revealed that the composite scaffolds promoted cell adhesion, proliferation, and osteogenesis. Fabricated scaffolds are a promising biomaterial candidate for bone substitution because of their attractive properties.

This paper describes the fabrication of polyelectrolyte microspheres using porous manganese carbonate as a sacrificial template for entrapped photosensitizer (PS) drugs for photodynamic therapy application. These particles were used as templates for polyelectrolyte layer-by-layer assembly (Lbl) of two oppositely charged polyelectrolytes: poly(styrene sulfonate) and poly(allylamine hydrochloride). When the polyelectrolyte multilayer shell was built around the MnCO3 core by the Lbl protocol and the core was extracted with acid solution and EDTA, the resultant assembly consisted of hollow polyelectrolyte spheres. Chloroaluminum phthalocyanine was chosen as the model drug to load into the hollow spheres. All the spectroscopic results presented showed excellent photophysical parameters of the studied drug. The fabrication of polyelectrolyte hollow spheres can be used as an optimal medium for a variety of bioactive materials, which can also be encapsulated by the proposed method.

Bismuth (Bi)-based photocatalytic materials are widely used in the field of photocatalytic degradation of wastewater. In this study, β-Bi2O3/BiOBr heterojunction photocatalysts were prepared by an in situ chemical transformation method. BiOBr molecules are arrayed to cross each other to form a pore around β-Bi2O3. The prepared photocatalyst had a large specific surface area and excellent adsorption and photocatalytic properties. The β-Bi2O3/BiOBr with a molecular ratio of 11.1% had the highest catalytic activity. The result of a degradation experiment, performed with Rhodamine B (RhB) as the target pollutant, revealed that the degradation rate reached 99.85% after 25 min under visible light irradiation. The pore structure can adsorb contaminants and the heterojunction facilitates the separation of photogenerated electron–hole pairs to enhance the photocatalytic properties. The high adsorption performance and heterojunction achieved higher photocatalytic efficiency. This semiconductor photocatalyst with high adsorption performance provides a new approach to control water pollution.

A series of optically transparent and colorless semi-fluorinated poly(ether imide)s (PEIs) (III) were prepared from non-fluorinated 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) with various trifluoromethyl-substituted diamines. The III series showed more colorless and higher optical transparency with a cutoff absorption wavelength (λ0) below 370 nm than the IV series based on the corresponding non-fluorinated analogues and V series derived from CF3-free pyromellitic dianhydride (PMDA). Compared with the fluorinated VI series based on fluorinated 4,4′-hexafluoroisopropylidenediphthalic anhydride (6FDA), the semi-fluorinated III series not only exhibited much better optical transparency, but also had better mechanical and thermal properties. The III series had a tensile strength of 79.8–109.5 MPa, modulus of elasticity of 3.0–7.7 GPa and elongation at break of 14.2–26.7%, together with glass-transition temperatures (Tg) ranging from 214.3 to 265.1 °C and temperatures of 5% weight loss (T5%) beyond 530 °C. Meanwhile, the novel semi-fluorinated PEI IIIb was optically transparent and colorless with a λ0 of 367 nm coupled with dielectric constants below 3.2 and contact angles against water over 112°. In particular, the optically transparent IIIa exhibited the best tensile strength of 109.5 MPa when compared with already reported counterparts.

Lattice structures, defect structures, and deformation mechanisms of high-entropy alloys (HEAs) have been studied using atomistic simulations to explain their remarkable mechanical properties. These atomistic simulation techniques, such as first-principles calculations and molecular dynamics allow atomistic-level resolution of structure, defect configuration, and energetics. Following the structure–property paradigm, such understandings can be useful for guiding the design of high-performance HEAs. Although there have been a number of atomistic studies on HEAs, there is no comprehensive review on the state-of-the-art techniques and results of atomistic simulations of HEAs. This article is intended to fill the gap, providing an overview of the state-of-the-art atomistic simulations on HEAs. In particular, we discuss how atomistic simulations can elucidate the nanoscale mechanisms of plasticity underlying the outstanding properties of HEAs, and further present a list of interesting problems for forthcoming atomistic simulations of HEAs.

The creep behavior of 200-nm thick gold films was investigated by plane-strain bulge testing between 23 and 100 °C. The polycrystalline gold films were produced by thermal evaporation and their columnar microstructure was stabilized by a preliminary heat treatment at 120 °C. The creep tests were performed at constant stress values between 80 and 300 MPa over 12 h, using a custom-built bulge tester. The stress exponent calculated from the creep data decreased from 4.3 to 2.8 between 23 and 100 °C, suggesting a possible transition in deformation mechanisms. The stress exponent and activation energy measured around room temperature point toward the climb of dislocations at grain boundaries being the rate-limiting deformation mechanism. Above 75 °C, scanning electron microscope inspections of tested membranes suggest an increased contribution of diffusion and of grain-boundary mediated deformation, as evidenced by the formation of grooves along grain boundaries. This is presumably the reason for the decrease of the apparent stress exponent and sudden increase of the apparent activation energy.

Antiperovskite materials are of high research interest because of their unusual physical properties and technological applications. Here, we report the structural stability and transport properties of Sr3AsN from first-principles study. The calculated equilibrium lattice parameters are in good agreement with the available data. We find that Sr3AsN is mechanically, energetically and dynamically stable at ambient conditions. Our calculated electronic structure indicates that it is a direct band gap semiconductor, with a band gap value ∼1.2 eV. Sr-4d and N-2p orbitals predominantly contribute to the formation of the direct band gap. The calculated Seebeck coefficient of Sr3AsN is high (298 μV/K at 300 K), while the lattice thermal conductivity is comparatively low (1.73 W/m K). The considerable mass difference between Sr, As, and N gives rise to an intense phonon scattering that results in such low lattice thermal conductivity. Our calculated maximum thermoelectric figure of merit (ZT) is 0.75 at 700 K, indicating that it is a potential material for thermoelectric device applications.

Two rapidly solidified (RS) Mg ribbons with the compositions of Mg97Zn2Gd1 and Mg90Zn5Gd5 (at.%) were first prepared by the planar flow casting method. These RS ribbons were subsequently consolidated by spark plasma sintering (SPS). The use of SPS on the RS ribbons was demonstrated to be an effective processing route to control W-phase precipitation process while keeping fine grains. The size of W-phase particles was less than 200 nm in Mg97Zn2Gd1 alloy and smaller than 500 nm in Mg90Zn5Gd5 alloy. The content of W phase was approximately 34 vol% and 41 vol% in the two SPS bulks, respectively. The compressive properties showed that the yield compressive stress (YCS) and ultimate compressive stress of the Mg97Zn2Gd1 alloy reached 200 MPa and 390 MPa, respectively, and an elongation of 0.24. The corresponding values for the Mg90Zn5Gd5 alloy were 313 MPa, 504 MPa, and 0.14, respectively. Based on the results of the quantitative analysis, W-phase nanoparticles with size less than 100 nm exhibited obviously strengthening effect in the Mg alloys. It highlighted that the W-phase nanoparticles contributed a large proportion of the YCS in the Mg97Zn2Gd1 alloy and a relatively small proportion for that of the Mg90Zn5Gd5 alloy.

Surface properties of titanium implants are key factors for rapid and stable bone tissue integration. So, in order to promote the osseointegration of implants, various surface treatments have been proposed. The objective of these surface treatments is to improve protein adsorption, cell adhesion and differentiation, and consequently, the tissue integration of titanium implants. In this paper, we propose to describe and compare the different strategies available in the literature to produce micro- and nanostructured surfaces on titanium, especially the recent results using electrochemical anodization. Anodization is a cost-effective process that produces nanostructures based on the electrolytic growth of columnar titanium oxide layers. By mastering the electrolyte composition and voltage, a regular array of pores with controlled diameters ranging from 15 to 200 nm are easily produced. Then we will present the latest results on the osteointegration of the surface composed anodized titania nanotubes.

Gelatin–chitosan–based scaffolds using different bioactive nano-ceramic phase such as hydroxyapatite (HAp), beta tri calcium phosphate (β-TCP) and 58 s bioactive glass (58 s BG) were fabricated at a fixed 30 wt% of bioceramic phase content. From FTIR spectrum of the composite scaffold, a red shift in amide I and amide II bonds from 1595 to 1545 cm−1 and a new absorption peak due to electrostatic interaction between Ca2+ and COO− were observed. Average pore size in all the composite scaffolds was in the range between 100 and 300 μm, significantly smaller than the average pore size of pure gelatin–chitosan scaffold. Gelatin–chitosan-58 s BG (GCB30) scaffold exhibited the highest amount of protein absorption of 23 mg/cm2 among all the prepared scaffolds after 36 h of incubation in bovine serum albumin (BSA) solution. Mesenchymal stem cell’s (MSC’s) proliferation onto GCB30 scaffold was significantly higher as compared to other prepared scaffolds up to 7 days of cell culture. Expression of both early marker (RUNX2) and late marker (Osteocalcin) of differentiation was higher in MSCs cultured onto GCB30 scaffold as compared to other prepared scaffolds.

Solar-grade multicrystalline silicon ingots as raw material for solar cells were obtained from upgraded metallurgical silicon by directional solidification in an axial magnetic field. The influence of preparation technology on the microstructural characteristics of silicon ingots was investigated. Governing equations were used to simulate the silicon fluid flow and thermal fields during directional solidification. The results show that appropriately increasing melt temperature and/or decreasing pulling-down rate can be conductive to the growth of a coarse columnar grain. Meanwhile, the axial magnetic field promotes the formation of low-energy ∑3 twin boundaries and reduces the dislocations and impurities, where the total concentration of major metal impurities is with a mean of 0.459 ppmw in the range of 1/9 to 8/9 of height along the growth direction. It is shown from the simulation results that suppressing silicon melt flow in both radial and azimuthal directions and reducing the growth rate in the edge regions contribute to the formation of a flat solid–liquid interface, which is more consistent with the experimental results. Moreover, the formation mechanism of the twins and removal mechanism of the impurities were discussed.

The effect of cooling rate on the microstructure evolution and the mechanical properties of ingots and rods of 2–5 mm diameter of (Ni0.92Zr0.08)100−xAlx (0 ≤ x ≤ 4 at.%) ultrafine eutectic composites have been investigated. The microstructure of the composites is comprised of micrometer size γ-Ni dendrites embedded in a nano/-ultrafine lamellar fcc γ-Ni and Ni5Zr matrix. The evolution of the microstructure at a wide range of cooling rates (10–104 K/s) has been analyzed in respect of volume fraction of the phases, lamellar spacing, and secondary dendritic arm spacing. All these composites exhibit high hardness up to 4.6 GPa and yield strength up to 1.6 GPa with large compressive plasticity up to 22% at room temperature. The effect of cooling rates on the strength and hardness, and the plasticity of the nanolamellar composites with wide range of alloy composition have been correlated.