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BACKGROUND: Vegetables are often blanched before drying. The hot‐water blanching (HWB) of broccoli reduces quality and is environmentally harmful. In this work, hot‐air‐assisted radio frequency heating blanching (HA‐RFB) of broccoli was developed for use before further drying processes. Blanching sufficiency, heating uniformity, and heating rate during HA‐RFB were investigated to improve the product's physicochemical properties and texture. Suitable heating conditions were achieved when HA‐RFB was applied with hot air at 70 °C, with an electrode gap of 10.7 cm, using a cylindrical container for the broccoli. RESULTS: Under these conditions, the relative peroxidase activity in broccoli decreased to 3.26% within 117 s, with 13.45% of weight loss. In comparison with HWB broccoli, the products blanched by HA‐RFB preserved their texture, bioactive compounds, and microstructure better. The ascorbic acid, sulforaphane, and total glucosinolate content in HA‐RFB products were 251.1%, 131.9% and 36.7% higher than those in HWB broccoli, and HA‐RFB treatment led to a greater weight loss (13.45 ± 0.50%) than HWB (8.70 ± 1.70%), which is very helpful for the subsequent drying process. CONCLUSION: This study demonstrated that HA‐RFB could be a promising substitute for HWB to blanch broccoli and other flower vegetables, especially as a pretreatment in the drying process. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

During the automatic powder‐feeding process, the hollow granulated mold fluxes are easily broken due to insufficient granule strength, which leads to dust pollution and the deterioration of the properties of mold fluxes during the continuous casting. Herein, a drum‐type granule strength testing device, laser granule size analyzer, and scanning electron microscope are used to analyze the attrition mechanism of three kinds of hollow granulated mold fluxes and the effect of microstructure on the attrition mechanism. The results show that: 1) the result of the drum‐type granule strength test is in good agreement with the practical application effect of mold fluxes; 2) abrasion has dominated the breakage of three kinds of mold fluxes and the dust pollution is caused by the generation of a large number of granules with granule sizes ranging from 20 to 80 μm; 3) the uniform and dense surface film structure on the surface of mold flux effectively inhibits the abrasion and improves the granule strength of mold flux; and 4) the difference in granule size and solubility of different raw materials in the spray granulation process leads to the deposition of Na2CO3, binder, and carbon black on the surface to form the film structure. [ABSTRACT FROM AUTHOR]

The effects of different rare earth elements on the microstructure, mechanical properties and wear resistance of WC/steel matrix composites were investigated in detail. The composite were successfully prepared through powder metallurgy vacuum sintering process, and the microstructures of different rare earth types were observed. The mechanical properties of the interfacial reaction phase Fe 3 W 3 C of the composites doped with rare earth elements were theoretically calculated by the first principles method, and the mechanical properties such as hardness, compressive strength, young's modulus and wear properties were tested, respectively. The results showed that the addition of a very small amount of rare earth elements did not change the type of microstructure. The compressive strength of the composites and the microhardness of the interface reaction zone (IRZ) were significantly improved, and the young's modulus of the IRZ was decreased, and the anisotropy of the composites was increased. The wear resistance of rare earth doped composites was higher than that of the undoped ones, which was mainly due to the fact that rare earth elements improved the strength and hardness of the composites. [ABSTRACT FROM AUTHOR]

Chemical erosion of reinforced concrete by Cl−, SO42− and Mg2+ in saline soil is the main factor of steel corrosion and concrete damage. In this study, the effects of different molar ratios of aqueous NaCl-MgSO4 on concrete macroscopic properties (appearance, weight change, compressive strength, and dynamic elastic modulus), ion content, microstructure, and porosity of concrete were investigated. The effects of different molar ratios on the macroscopic characteristics and erosion depth of concrete were revealed through concrete appearance, weight, mechanical properties, and SO42− and Cl− content. Analysis of the microstructural evolution process and complex mineral composition of concrete using various microscopic testing methods. The results showed that with increased salt concentration and erosion time, the weight change rate, compressive strength change rate, and relative dynamic elastic modulus of concrete samples had a trend of first increasing and then decreasing. The evolutionary process of transition from large pores to medium and small pores and then to large pores. In the early erosion stage, with increased MgSO4, corrosion products were deposited in pores and cracks, which refined the concrete pore structure and reduced ion diffusion speeds of Cl−, SO42−, and Mg2+. In the later erosion stage, corrosion products caused matrix damage and produced intersecting cracks, which promoted ion diffusion rates and induced deterioration of concrete macroscopic properties. During experiments, the binding ability of SO42− and Mg2+ ions to hydration products was found to be higher than that of Cl−. [ABSTRACT FROM AUTHOR]

The industrial importance of steel is reflected in the wear resistance, which is related to its changes of microstructure and temperature changes during heat treatment. Herein, C−Si−Mn−Cr steels are produced to understand the microstructure evolution and cooling characteristics during quenching in water and air. The samples of several feature points are selected along the radial direction from the treated steel, and the temperature distribution of steel is obtained via numerical simulations. The microstructures at different temperature feature points and the corresponding hardness are studied. The results show that the quenching processes with the water−air alternating cycle regulate the temperature distribution. Martensite and pearlite phases are primarily formed during water and air cooling, respectively. In the water−air alternating cycle quenching process, the microstructure includes bainite, martensite, and retained austenite. The obtained microstructure is more ideal and the value of hardness is 525.2 HV. The maximum hardness value is 695.3 HV for water quenching, while that for air cooling is 248.2 HV. The microstructure evolution of steel at different positions is closely related to the temperature change in varied quenching processes. [ABSTRACT FROM AUTHOR]

In this study, mold powder slurries with high solid loading and low viscosity were prepared during the ball-milling process for improving the homogeneity and mechanical properties of granules after spray-drying. The effect of ball-milling parameters, such as solid loading, binder/dispersant content, and ball-milling time, on the flowability, dispersibility, stability, and rheological behavior of mold powder slurries was systematically investigated by rheology observation and sedimentation tests. As these parameters varied, the slurry exhibited the shear-thinning behavior of a non-Newtonian fluid with a shear rate range of 0–50 s−1, which was adequately described by the Herschel-Bulkley model. The optimal parameters that optimized the flowability, dispersibility, and stability of the slurry, along with its rheological behavior, were chosen as follows: solid loading, 60 wt%; modified sodium carboxymethyl cellulose binder content, 1.0 wt%; sodium tripolyphosphate dispersant content, 0.5 wt%; ball-milling time, 60 min. [ABSTRACT FROM AUTHOR]

The effects of Gd content on crystalline orientation, microstructure and superconductivity of GdxY1−xBa2Cu3O7−δ (GdYBCO) films were systematically investigated. By varying the Gd content in the liquid precursor without changing the total amount of rare earth elements, series of GdYBCO films with x values of 0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0 were fabricated by metal organic chemical vapor deposition (MOCVD). X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis revealed that Gd introducing could restrain the formation of CuYO2 phase, but induce a-axis growth of GdYBCO film. The increase of x from 0 to 0.5 leads to enhancing critical current density at self-field and 77 K (Jcsf) from 1.8 to 2.8 MA·cm−2, which benefits from the decrease in CuYO2 impurities and improvement of in-plane texture from 5.0° to 4.3°. However, raising x from 0.5 to 1.0 gives rise to abundant a-axis growth of film and degradation of in-plane texture from 4.3° to 5.4°, consequently resulting in the decrease of Jcsf from 2.8 to 0.8 MA·cm−2. Even though Jcsf has not varied monotonically, the critical transition temperature of GdYBCO films linearly increases from 90.75 to 92.25 K and the in-field performance at magnetic field (B) of 0-1.1 T and 77 K as well as B parallel to film normal is also superior with Gd content increasing. [ABSTRACT FROM AUTHOR]

Despite the rapid increase in the performance of perovskite solar cells (PSC), they still suffer from low lab-to-lab or people-to-people reproducibility. Aiming for a universal condition to high-performance devices, we investigated the morphology evolution of a composite perovskite by tuning annealing temperature and precursor concentration of the perovskite film. Here, we introduce thermal annealing as a powerful tool to generate a well-controlled excess of PbI2 in the perovskite formulation and show that this benefits the photovoltaic performance. We demonstrated the correlation between the film microstructure and electronic property and device performance. An optimized average grain size/thickness aspect ratio of the perovskite crystallite is identified, which brings about a highly reproducible power conversion efficiency (PCE) of 19.5 %, with a certified value of 19.08 %. Negligible hysteresis and outstanding morphology stability are observed with these devices. These findings lay the foundation for further boosting the PCE of PSC and can be very instructive for fabrication of high-quality perovskite films for a variety of applications, such as light-emitting diodes, field-effect transistors, and photodetectors. [ABSTRACT FROM AUTHOR]

The microstructures, phase transformations, mechanical properties and shape memory effect of Ti-20Zr-10Nb-xAl (x=1, 2, 3, 4 at%) alloys were investigated. The X-ray diffraction results show that the alloys are composed of a single martensitic α″-phase and that the corresponding unit cell volume decreases with increasing Al content. The reverse martensitic transformation start temperature ( A s ) of the Ti-20Zr-10Nb-Al alloy is 534 K and decreases with increasing Al content. The addition of Al results in solid solution strengthening and grain refinement strengthening, thus improving the mechanical properties and the shape memory effect of the Ti-20Zr-10 Nb-xAl alloys. The Ti-20Zr-10Nb-3Al alloy shows the greatest shape memory strain (3.2%) and the largest tensile strain (17.6%) as well as a very high tensile strength (886 MPa). [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of steel play important roles in its wear resistance. In this study, low alloy medium carbon steel was prepared by alternating quenching in water and air for up to 3 cycles, followed by air cooling (AC) to room temperature (RQ), to obtain different microstructures. The mechanical and impact abrasive wear properties of the steel were tested under different alternating cycles, and the influence of the microstructure on the wear properties and mechanism was analyzed. The microstructure of the steel gradually changed from pearlite and ferrite to fine bainite, martensite, and retained austenite during the quenching process with an increase in the water-air alternation cycles. Compared with no alternation quenching cycle, the steel after alternating 3 cycles had the best combination of hardness, toughness, and wear resistance; that is, the hardness and impact toughness increased from 245 to 464 HV, and 28–50 J/cm2, respectively, and the impact wear resistance increased from 4.99 g-1 to 12.31 g-1. This was mainly owing to the multiphase microstructure, such as bainite/martensite, increasing the dislocation density of the sample and improving the mechanical properties of the steel, and the work-hardening of the retained austenite in the wear surface under the impact deformation, which improved the wear resistance of the steel. [Display omitted] • Different types of microstructures can be obtained by alternating cycles in water and air. • Hardness and impact toughness of the steel increased from 245 to 464 HV, and 28–50 J/cm2. • The wear resistance with bainite/martensite is nearly 2.5 folds higher than that of pearlite. • Wear mechanism changed from cracking and spalling to plowing and micro-cutting. [ABSTRACT FROM AUTHOR]

Samples made of a super high strength aluminum alloy with high Zn content were friction stir welded with rotation rates of 350–950 rpm and welding speeds of 50–150 mm/min. The effect of welding parameters on the microstructure and mechanical properties was investigated. It was observed that the grain size of the nugget zones decreased with the increasing welding speed or the decreasing tool rotation rate. Most of the strengthening precipitates in the nugget zone were dissolved back and the intragranular and grain boundary precipitates in the heat affected zone coarsened significantly. The greatest ultimate tensile strength of 484 MPa and largest elongation of 9.4 were obtained at 350 rpm−100 mm/min and 350 rpm−50 mm/min, respectively. The ultimate tensile strength and elongation deteriorated drastically when rotation rate increased from 350 to 950 rpm at a constant welding speed of 100 mm/min. [ABSTRACT FROM AUTHOR]

The effect of sintering conditions and concomitant microstructure of dental zirconia (ZrO2) ceramics on their low-temperature degradation (LTD) behavior remains unclear. Objectives: Therefore, their effect on LTD of dental ZrO2 ceramics was investigated. Methods: Three commercial pre-sintered yttria-stabilized dental zirconia materials were sintered at three temperatures (1450°C, 1550°C and 1650°C) applying three dwell times (1, 2 and 4h). Grain size measurements and LTD tests were performed on polished sample surfaces. LTD tests were performed at 134°C in an autoclave. The amount of monoclinic ZrO2 on the exposed surface was measured by X-ray diffraction (XRD). Results: Higher sintering temperatures and elongated dwell times increased the ZrO2 grain size. Simultaneously, a larger fraction of zirconia grains adopted a cubic crystal structure, resulting in a decreased yttria content in the remaining tetragonal grains. Both the larger grain sizes and the lower average stabilizer content made the tetragonal grains more susceptible to LTD. Overall, independent on the commercial dental zirconia grade tested, the specimens sintered at 1450°C for 1h combined good mechanical properties with the best resistance to LTD. Significance: In general, increased sintering temperatures and times result in a higher sensitivity to low-temperature degradation of Y-TZP ceramics. [ABSTRACT FROM AUTHOR]

LaZrO (LZO) film directly deposited on Ni-5 at.%W by a chemical solution technique, metal organic decomposition (MOD), indicated a poor texture characteristic, which would result in high-angle grain boundaries in subsequent YBaCuO (YBCO) associated with weak-link behavior. Different ultrathin MOD-LZO, YO, and CeO seed layers (~several nanometers) with various annealing temperature were inserted to improve the crystallographic alignment. The relation between the texture and annealing temperature was systematically investigated. A CeO seed layer allows us to grow high quality LZO epitaxial films with values of full width at half-maximum around 5.61° and 5.13° for the Φ-scan of (222) and rocking curve of (400) LZO, respectively, which is comparable to the microstructure of films grown using physical vapor deposited YO as a seed layer. This buffer template, serving for YBCO coated conductors, could potentially decrease the overall fabrication cost. [ABSTRACT FROM AUTHOR]

The fundamental framework of doublet mechanics (DM) is used to analyze high-frequency ultrasound wave propagation in materials with discrete microstructure. Ultrasonic reflection coefficients were measured from a thin layer of tissue embedded between two glass substrates at oblique incidence. Theoretical calculations for the reflection coefficients of a multi-layered system at oblique angles are performed using both DM theory and the classical continuum mechanics theory (CCM). For example, at the frequency of 10 MHz at incident angle 8° in sample with 30 μm thickness, the discrepancy in the magnitude of the reflection coefficient between experimental results and theoretical prediction is 15.8% for DM but 79.0% for CCM; similar results at other frequencies and incident angle in the samples with 30 and 60 μm thickness have also been obtained, which demonstrates that the DM theory can better describe the wave propagation in tissue. The influence of the incident angles and tissue thickness are also discussed in this paper. [ABSTRACT FROM AUTHOR]

The diffusion of sulfate (SO42−) and chloride (Cl−) ions from rivers, salt lakes and saline soil into reinforced concrete is one of the main factors that contributes to the corrosion of steel reinforcing bars, thus reducing their mechanical properties. This work experimentally investigated the corrosion process involving various concentrations of NaCl-Na2SO4 leading to the coupled erosion of concrete. The appearance, weight, and mechanical properties of the concrete were measured throughout the erosion process, and the Cl− and SO42− contents in concrete were determined using Cl− rapid testing and spectrophotometry, respectively. Scanning electron microscopy, energy spectrometry, X-ray diffractometry, and mercury porosimetry were also employed to analyze microstructural changes and complex mineral combinations in these samples. The results showed that with higher Na2SO4 concentration and longer exposure time, the mass, compressive strength, and relative dynamic elastic modulus gradually increased and large pores gradually transitioned to medium and small pores. When the Na2SO4 mass fraction in the salt solution was ≥10 wt%, there was a downward trend in the mechanical properties after exposure for a certain period of time. The Cl− diffusion rate was thus related to Na2SO4 concentration. When the Na2SO4 mass fraction in solution was ≤5 wt% and exposure time short, SO42− and cement hydration/corrosion products hindered Cl− migration. In a concentrated Na2SO4 environment (≥10 wt%), the Cl− diffusion rate was accelerated in the later stages of exposure. These experiments further revealed that the Cl− migration rate was higher than that of SO42−. [ABSTRACT FROM AUTHOR]

Herein, the effects of height-diameter ratios (H/D) on the microstructure evolution and mechanical properties of 0.4C-Si-Mn-Cr steel during high temperature deformation are reported. The compression experiments were performed on steel samples using Gleeble to obtain a reasonable deformation temperature, and the degree of deformation was assessed in the range of 1.5 to 2.0 H/D via forging. The forged specimens were quenched using the same heat treatment process. The hardness and impact toughness of the steel samples were tested before and after heat treatment. Grain sizes gradually increased with an increase in the compression temperature from 950 °C to 1150 °C, and the grain sizes decreased with an increase in H/D. The microstructure of the steel samples contained pearlite, bainite, martensite, and retained austenite phase. The microstructure after forging was more uniform and finer as compared to that of as-cast steel samples. The hardness and impact toughness of the steel samples were evaluated after forging; hardness first increased and then decreased with an increase in H/D, while the impact toughness continuously increased with an increase in H/D. Hence, the microstructure and properties of steel could be improved via high temperature deformation, and this was primarily related to grain refinement. [ABSTRACT FROM AUTHOR]

High-strength, multiphase steels consisting of pearlite surrounded by tempered martensite were prepared by pre-quenching and ultrafast tempering heat treatment of high-carbon pearlitic steels (0.81% C). The microstructures were analyzed by scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy. With an increasing quenching temperature from 120 °C to 190 °C, the quenched martensite variants nucleated via autocatalytic nucleation along the interface. Furthermore, the tempered nodules exhibited a distinct symmetrical structure, and the tempered martensite and pearlitic colonies in the group also showed a symmetrical morphology. In addition, a reasonable model was formulated to explain the transformation process from quenching martensite to the multiphase microstructure. When the quenching temperature was set to 120 °C, followed by ultrafast heating at 200 °C/s to 600 °C and subsequent isothermal treatment for 60 s, the multiphase structure showed highest strength, and the pearlite volume fraction after tempering was the lowest. The microhardness softening mechanism for the tempered structures consisted of two stages. The first stage is related to martensitic sheets undergoing reverse transformation and the nucleation of cementite on dislocations. The second stage involves the transformation of austenite into pearlite and continued carbide coarsening in the martensitic matrix. [ABSTRACT FROM AUTHOR]

WC/Fe matrix composites with mass fractions of 30–50 wt% were prepared by gravity casting and infiltration, and the phase composition, microstructure, friction and wear properties of the composites were studied. In addition, the mechanism of the effect of the change of WC mass fraction on the structural evolution and wear properties of the composites was particularly investigated. The results show that the composites are mainly composed of WC, α-Fe, W 2 C, Fe 6 W 6 C, and M 7 C 3 phases. With the increase of WC mass fraction, the microstructure of the composite shows different results, WC particles start to dissolve under the action of high temperature melt, W elements solidly dissolve into the matrix and precipitate into fishbone structure carbide. As the content of WC particles in the prefabricated body increases, the C atoms around the WC particles react with the dissolved W atoms, and due to the cooling of the metal liquid, the energy transferred between the WC and the metal liquid does not make it melt completely before solidification occurs, and the metallurgical reaction between the WC particles and the substrate occurs and produces a dense interface. The WC/Fe matrix composites showed a trend of increasing and then decreasing with the increase of WC content and friction coefficients of 0.36, 0.52, and 0.26. The wear rates were 1.52(mm3/N-m) × 10−5, 1.24(mm3/N-m) × 10−5, and 1.57(mm3/N-m) × 10−5, which showed the opposite trend with the friction coefficients, and the wear rates were compared with the morphology. When the composite was added with 40% WC, the wear rate increased by 27% compared with other parameters. It shows that it has good wear resistance. • WC/Fe matrix composites were prepared by varying the WC mass fraction and using a gravity casting process. With the increase of WC mass fraction, the microstructure of the composites showed different results. • The stress concentration on the outer side of the interface was found by EBSD, and this phenomenon also proved that the cracks in the WC particles under wear-resistant condition sprouted from the interface matrix and then extended to the WC particles. • With the increase of WC content in the prefabricated body, the wear resistance showed a trend of first increasing and then decreasing, revealing a direct correlation mechanism between the microstructure of the composite and the wear test. [ABSTRACT FROM AUTHOR]

The phase transformation behavior and microstructural evolution of the Ti-19.5Zr-10Nb-0.5Fe alloy upon heating and cooling have been investigated by X-ray diffraction spectroscopy, differential scanning calorimetry, thermal dilatation and transmission electron microscopy. The results show that the Ti-19.5Zr-10Nb-0.5Fe alloy is mainly composed of the orthorhombic α″-martensite phase as well as a small amount of β-phase at room temperature. The reverse transformation of the α″-martensite phase to the β-phase occurs at 429 K and finishes at 449 K. The nanoscale hexagonal ω-phase particles continuously precipitate at approximately 533 K and co-exist with the β-phase even up to 593 K. When heated to 683 K, the acicular α-phases nucleate at the interfaces between the coarsened ω-phase precipitate and β-phase, and then grow up at the expense of the ω-phase and β-phase with the increasing temperature up to 773 K. The fraction of α-phase decreases during the subsequent heating, leaving the β-phase exclusively remained at 873 K. Upon cooling from 873 K, the β-phase partially transforms into the α″-martensite phase. The measurements of the microhardness indicate the hardening effect of the ω-phase precipitate and accord with the phase evolution behavior in the Ti-19.5Zr-10Nb-0.5Fe alloy. [ABSTRACT FROM AUTHOR]

The high-entropy alloy coatings of FeCoCrNiCuB x (x = 0, 0.1, 0.3, 0.5, x values are molar ratios) were prepared on the surface of Q235 steel by laser cladding. The microstructure, microhardness, and surface energy of the FeCoCrNiCuB x coatings were investigated, and the tribological property and wear mechanism of the composite coatings at room temperature (RT) and 600 ℃(HT) were analyzed. The FeCoCrNiCu coating consists of a single FCC-type solid solution. When x = 0.3, 0.5, the composite coatings appear the Cr 2 B phase. The x = 0.5 (B5) coating has the lowest surface energy (27.45mN/m), which is one of the reasons it has excellent tribological properties. The tribological properties of FeCoCrNiCuB x composite coatings were improved at both RT and HT. The B5 coating has excellent tribology at both RT and HT. At RT, the wear resistance of the B5 coating (wear rate is 8.54 ×10−5 mm3/N∙m, coefficient of friction (COF) is 0.51) was improved by 54.79%, 50.89%, and 12.86% compared with x = 0(HEA), x = 0.1(B1), and x = 0.3(B3), respectively, the COF reduced by 42.69%, 41.39%, 22.73%. At HT the wear resistance of the B5 coating (wear rate is 6.69 ×10−5 mm3/N∙m, COF is 0.24) was increased by 71.53%, 52.91%, and 49.42% compared to HEA, B1, and B3, respectively, the COF reduced by 29.41%, 25.00%, 17.24%. The wear mechanisms of coatings that add B element at RT are abrasive wear and fatigue wear, and at HT are mainly oxidative wear, moderate abrasive wear and fatigue wear.B 2 O 3 melts at HT to form a low-viscosity liquid that forms a lubricating film that isolates the contact surfaces and reduces direct contact and adhesion. This is the main reason for the excellent friction properties of B5 coating at HT. [ABSTRACT FROM AUTHOR]

The microstructure, phase transformation, mechanical properties and shape memory effect of Ti–19.5Zr–10Nb–0.5Fe alloy have been investigated. Ti–19.5Zr–10Nb–0.5Fe alloy is mainly composed of orthorhombic α″-Martensite as well as a small amount of β phase. The alloy exhibits a two-stage yielding in tension with a tensile strain of 21%. The corresponding maximum shape memory strain is as large as 4.1%, associated with a reverse martensitic transformation occurring at 429 K. [ABSTRACT FROM AUTHOR]

Abstract: A compositionally modified Ni–45Ti–5Al–2Nb–1Mo (at%) alloy was developed by simultaneously adding Nb and Mo in NiTi–Al-based alloy and processed by forging isothermally. The as-forged Ni–45Ti–5Al–2Nb–1Mo alloy consists of NiTi matrix, Ti2Ni and dispersive (Nb,Ti)SS phases. Mo addition reduces the solubility of Nb in the NiTi matrix and gives rise to the precipitation of numerous nanoscale (Nb,Ti)SS phases (bcc structure) within the grains. The (Nb,Ti)SS phase is semi-coherent to the NiTi matrix with a lattice misfit of 6.7%. The addition of Mo and Nb dramatically enhances the NiTi–Al alloy at high temperatures, which is mainly attributed to the solid solution strengthening of Nb and Mo elements as well as the precipitation strengthening of (Nb,Ti)SS phases. The Ni–45Ti–5Al–2Nb–1Mo alloy is expected to become a high-temperature structural material using at intermediate temperatures with strengths of 650MPa at 923K and 350MPa at 1073K. [Copyright &y& Elsevier]

• Type of alumina precursor considerably influenced the microstructure of 12Ce-TZP based ATZs. • The elongated lanthanum hexa-aluminate was much finer when using γ-AlOOH and Al(NO 3) 3 ·9H 2 O as Al 2 O 3 precursors. • The fine elongated lanthanum hexa-aluminate leading to a strong toughening effect. • γ-AlOOH resulted in a fracture resistance of 9.7 MPa m1/2, biaxial bending strength of σ 0 = 976 MPa and reliability of m = 20.7. Three different alumina sources (boehmite, aluminium nitrate and α-alumina particles) and 12Ce-TZP powder containing 1 wt% lanthanum oxide were used to prepare 12Ce-TZP-based alumina-toughened-zirconia (ATZ) composites. The obtained ATZs had similar density and phase composition, whereas the microstructures were significantly different. Alumina-particle addition gave rise to a typical ATZ microstructure consisting of equiaxial sub-micrometer zirconia and alumina phases, while the lanthanum hexa-aluminate phase was formed in large and non-homogenously distributed precipitates (∼3.5 μm in length). The boehmite and aluminium nitrate-based composites contained not only sub-micrometer equiaxial alumina and zirconia grains but also small-sized lanthanum hexa-aluminate precipitates (∼1.2 μm in length) that were inter- and transgranularly positioned in the zirconia matrix and effectively promoted crack deflection and toughening. In combination with a higher t -ZrO 2 transformability, the boehmite-based composites had a higher indentation fracture resistance, strength and reliability compared to the aluminium-nitrate and alumina-particle based equivalents. [ABSTRACT FROM AUTHOR]

• The strain induced α″-martensite formed in the β Ti-30Zr-10Nb alloy upon tension. • The strain induced α″-martensite was stabilized at room temperature. • A s temperature of strain induced α″-martensite increases with increasing prestrain. • Shape memory recovery occurred in the deformed Ti-30Zr-10Nb alloy on heating. An unusual phenomenon of strain induced martensite stabilization in the β-type Ti-30Zr-10Nb shape memory alloy was studied. The strain induced α″-martensite formed in the β phase during the tensile loading on the metastable Ti-30Zr-10Nb alloy. It was stabilized at room temperature and thus no superelastic recovery occurs in the alloy upon unloading. The reverse transformation temperature of the strain induced α″-martensite increased from 333 K to 369 K with increasing pre-strain from 2% to 8%. Shape memory recovery occurred in the pre-strianed Ti-30Zr-10Nb alloy upon heating. The maximum shape memory effect of the alloy was 3.5% with the pre-strain of 8%. [ABSTRACT FROM AUTHOR]

The metal organic chemical vapor deposition (MOCVD) method was used to prepare GdYBCO films on LaMnO 3 / homo epitaxial-MgO/ ion-beam-assisted-deposition-MgO/ solution-deposition-planarization-Y 2 O 3 buffered Hastelloy tapes. By adopting a simple self-heating technique, the substrates were heated by the joule effect after applying a heating current ( I h ) through Hastelloy metal tapes. The effects of substrate temperature and (Gd, Y)/Ba ratio ( r c ) in the precursor on the biaxial texture, surface morphology and superconducting performance of GdYBCO films were systematically investigated by varying the values of I h and r c . Needle-like outgrowths formed on the substrate surface were characterized using a scanning electron microscope, energy dispersive spectrometer and X-ray diffraction system. The results show that a high I h or r c leads to the formation of needle-like outgrowths. Therefore, I h and r c are crucial process parameters that control the growth of needle-like outgrowths on the surface of GdYBCO films. Three hundred nanometer thick GdYBCO films were prepared at different I h and r c by the MOCVD process. At an I h of 27.0 A and an r c of 0.6, the surface of the GdYBCO film was very smooth and dense, which can provide a good template for multiple depositions of GdYBCO films. The critical current density of the deposited 300 nm-thick GdYBCO film was 4.4 MA/cm 2 (77 K, 0 T), which is attributed to good biaxial texture and appropriate film composition. Furthermore, the microwave surface resistance (77 K, 10 GHz) of the GdYBCO film was merely 0.581 mΩ. [ABSTRACT FROM AUTHOR]

The microstructures, phase transformations and shape memory properties of Ti-30Zr-xNb (x = 5, 7, 9, 13 at.%) alloys were investigated. The X-ray diffraction and transmission electron microscopy observations showed that the Ti-30Zr-5Nb, Ti-30Zr-7/9Nb and Ti-30Zr-13Nb alloys were composed of the hcp α′-martensite, orthorhombic α″-martensite and β phases, respectively. The results indicated the enhanced β-stabilizing effect of Nb in Ti-30Zr-xNb alloys than that in Ti-Nb alloys due to the high content of Zr. The differential scanning calorimetry test indicated that the Ti-30Zr-5Nb alloy displayed a reversible transformation with a high martensitic transformation start temperature of 776 K and a reverse martensitic transformation start temperature ( A s ) of 790 K. For the Ti-30Zr-7Nb and Ti-30Zr-9Nb alloys, the martensitic transformation temperatures decreased with the increasing Nb content. Moreover, an ω phase transformation occurred in the both alloys upon heating at a temperature lower than the corresponding A s , which is prompted by more addition of Nb. Although the critical stress in tension of the three martensitic alloys decreased with increasing Nb content, the Ti-30Zr-9Nb alloy showed a critical stress of as high as 300 MPa. Among all the alloys, the Ti-30Zr-9Nb alloy exhibited the maximum shape memory effect of 1.61%, due to the lowest critical stress for the martensite reorientation. [ABSTRACT FROM AUTHOR]

Thin and compact zeolite chabazite membranes were prepared by microwave heating using symmetric stainless steel tubular supports. The microstructures (crystal size and membrane thickness) and separation performances of supported chabazite layers were strongly affected by heating method, synthesis time and synthesis temperature. The best membrane prepared by microwave heating under optimized conditions showed fluxes of 7.3 and 9.1 kg/(m 2 h) and separation factors of 2000 and 2500 for 90 wt.% ethanol and isopropanol aqueous solutions at 348 K, respectively. These fluxes were twice as high as those of the chabazite membranes prepared by conventional heating due to the thinner zeolite layers and lower resistance of the support layer in the microwave heating system. The membrane prepared on the 3-time-reused stainless steel support showed comparable separation performance with the membrane on the fresh support, suggesting that the stainless steel supports had a good reuse prospect for chabazite membrane preparation. Synthesis reproducibility and hydrothermal stability of chabazite membranes by microwave heating were also investigated. [ABSTRACT FROM AUTHOR]

Abstract: In this study, laser ablation of a fluorine-doped tin oxide (FTO) thin film on a glass substrate was conducted using a 355nm Nd:YVO4 ultraviolet (UV) laser to obtain a 4×4mm microstructure. The microstructure contains a symmetric set of interdigitated FTO finger electrodes of a monolithic back-contact dye-sensitized solar cell (BC-DSC) on a common substrate. The effects of UV laser ablation parameters (such as laser fluence, repetition frequency, and scanning speed) on the size precision and quality of the microstructure were investigated using a 4×4 orthogonal design and an assistant experimental design. The incident photon-to-electron conversion efficiency and the current–voltage characteristics of the BC-DSC base of the interdigitated FTO finger electrodes were also determined. The experimental results show that an FTO film microstructure with high precision and good quality can be produced on a glass substrate via laser ablation with high scanning speed, high repetition frequency, and appropriate laser fluence. [Copyright &y& Elsevier]