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Ni-P nanoglass consisting of nanometer-sized amorphous grains separated by amorphous interfaces was prepared by a specially designed multi-phase pulsed electrodeposition technique. The microstructure of the deposited Ni-P nanoglass was confirmed by X-ray diffraction, high-resolution transmission electron microscopy, small-angle X-ray scattering, and X-ray photoelectron spectroscopy. The formation of the Ni-P nanoglass, which is characterized by inhomogeneities on the nanometer length scale, is achieved via proper control of the rate of cluster formation and cluster growth by a multi-phase pulsed electrodeposition process.

The high strength of 300M steel originates from the heat treatment process after forging, but how hot deformation affects the heat-treated microstructure and mechanical properties is unclear. In this study, compression tests under different hot deformation parameters and post-deformation heat treatment experiments were carried out, and the martensite transformation process was investigated using in situ observation. The results show that the grain size of the specimen deformed at low temperature and high strain rate is smaller, and annealing twins will be formed. Both austenite grain boundaries and twin boundaries hinder the growth of martensite blocks, reducing the size of martensite units after heat treatment and thus resulting in higher yield strength. Besides, the mathematical models were established to describe the relationship between hot deformation parameters and grain size after deformation, martensite packet size and martensite block width, respectively, after heat treatment. The relationship between yield strength and hot deformation parameters was also analyzed. According to the results and models, the hot deformation parameters would be optimized more reasonably to improve the final mechanical properties of 300M steel forgings. [ABSTRACT FROM AUTHOR]

Underwater acoustic stealth has great scientific research value. According to acoustic coordinate transformation theory, the acoustic stealth cloak based on pentamode materials can realize underwater broadband acoustic stealth. However, due to the correlation between the density and modulus of pentamode materials and the changes in the parameters of each layer of the acoustic stealth cloak, a large amount of structural optimization work is required for the pentamode material to meet the specific parameter requirements, which significantly increases the difficulty of the pentamode acoustic stealth cloak design. To simplify the design process, inspired by the calculation of equivalent modulus by representation volume element, this article proposed a pentamode material configuration with independent variation of density and modulus and designed a 1 m radius acoustic stealth cloak with a specific structure of pentamode materials matching the coordinate transformation equation of constant modal mapping. After simulation calculation and optimization design, in the range of a / λ from 0 to 1, the average total scattering cross-section of the cavity with a radius of 0.5 m covered by the acoustic stealth cloak is 0.858; the average total scattering cross-section of the cavity is 19.718 after removing the pentamode material acoustic stealth cloak. The results of the study are expected to provide some method references for simplifying the design process of the pentamode material acoustic stealth cloak and the microstructure design of the pentamode materials. [ABSTRACT FROM AUTHOR]

The paper summarizes the current development of high-velocity oxygen–fuel coupled physical vapor deposition (HVOF-PVD) duplex coatings as protective candidates. Following a detailed historical overview of HVOF and PVD technologies, the fabrication methods for duplex protective coatings are presented. The duplex coating superimposes the synergistic advantages of coatings deposited by HVOF and PVD, where the traditional weaknesses of each technique are modified to a great certain extent. Subsequently, the relation between structural characteristics of the duplex coatings and their mechanical, tribological, and corrosive behavior is described in detail. It is demonstrated that the duplex coatings show more excellent overall performance than coatings deposited by both HVOF and PVD separately. Finally, we summarize the protective performance and promising potential of HVOF-PVD duplex coating for applications as well as the research prospects of challenges in future. [ABSTRACT FROM AUTHOR]

Herein, CoCrxCuFeMnNi (x = 0, 0.5, 1.0, 1.5, and 2.0, in molar ratio) high‐entropy alloys (HEAs) are prepared through vacuum hot‐pressing sintering. The influences of Cr content on the microstructure and the corrosion behavior in 3.5% NaCl solution are studied. The alloys are mainly composed of two face‐centered cubic (FCC) phases, namely, Cr–Co–Fe–Mn–Ni (or Co–Fe–Mn–Ni)‐rich FCC1 phase and Cu–Mn–Ni‐rich FCC2 phase. With the increase of Cr content, The FCC1‐phase area expands and the FCC2 phase area shrinks. In 3.5% NaCl solution, the corrosion current density (icorr) and average corrosion rate (Vcorr) of the HEAs decrease with the increase in Cr content. The icorr and Vcorr of Cr2.0 alloy are lower at 1.87 × 10−6A cm−2 and 0.02 mm year−1, respectively. The increase of transfer resistance (Rp) and decrease of relative thickness (CPE1−1) of the passivation film indicate that the more difficult it is for ions in the corrosive medium to pass through the capacitor layer, the better the corrosion resistance of the alloy. Improvement of the corrosion resistance is mainly due to the formation of denser Cr2O3 passivation film and reduction of the segregation degree of Cu in the FCC2 phase. [ABSTRACT FROM AUTHOR]

Background and objectives: Steamed bread is the traditional fermented wheat product in China and has popularity in other Asian, European, and some North American countries. Wheat flour replaced by potato pulp can be an effective way to improve nutritive values of steamed bread and promote potato consumption. The aim of this study was to investigate the influences of potato pulp on disulfide bond (S–S) contents, protein secondary structures, starch crystallinity, and microstructures of dough and steamed bread. Spectrophotometry, Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM) were used for analyses. Findings: The dough and steamed bread samples added with 10% potato pulp had higher S–S contents than the other tested samples. Compared with the control, the free sulfhydryl contents in the dough (3.2 μmol/g) and steamed bread (2.7 μmol/g) added with 30% potato pulp significantly increased, whereas those of the S–S decreased to 10.0 and 10.9 μmol/g, respectively. The contents of β‐sheet and α‐helix in the dough and steamed bread containing 10% potato pulp were higher than those in samples without the potato pulp. The relative crystallinity of starch in the dough significantly decreased with increasing potato pulp level (p <.05). The CLSM and SEM images showed that potato pulp significantly affected the microstructure. Sample with 10% potato pulp possessed improved gluten network structures. However, samples with high potato pulp contents (>20%) possessed more gas cells and a loose gluten network structure. Conclusions: The results showed that the addition of potato pulp affected gluten network structural characteristics in wheat flour dough and steamed bread, but appropriate level of potato pulp could be produced for gluten network enhancement. Significance and novelty: The study would contribute to better understanding of the effect of potato pulp on the structural characterization of gluten network in steamed bread making and provide theoretical basis for in‐depth application to wheat‐based products. [ABSTRACT FROM AUTHOR]

Abstract Diamond-like carbon (DLC) films with weak carbide metal Al and carbide metal Ti co-doping (Al/Ti-DLC) were prepared by a hybrid ion beam deposition system. The atomic ratios of doped Al to Ti were tailored via designing the special Al/Ti combined sputtering target. The composition, microstructure, roughness, residual stress, hardness, toughness, and tribological behaviors of the deposited films were systematically evaluated to explore the dependence of structural properties on Al/Ti ratios. Results indicated that the high-throughput preparation of DLC films with different Al/Ti atomic ratios was achieved by tailoring the sputtering target and process parameters without the difference in both the film thickness and total Al/Ti content. With the Al/Ti ratios in the films decreased from 8.8 to 3.0, the residual stress, hardness, and toughness of Al/Ti-DLC films increased obviously, originating from the increased fraction of titanium carbide and the reduced Al content. However, the coefficient of friction and wear rate with decreasing the Al/Ti ratio were obviously improved, which was related with the transformation of underlying friction mechanism from the sliding interface graphitization to dangling bond-passivation. The present results not only suggest a high-throughput method to fabricate co-doped DLC films, but also promote the scientific understanding and engineering application of DLC films with high performance. Highlights • Ti/Al co-doped diamond-like carbon films were fabricated by a hybrid ion beam method. • Different Al/Ti ratios were successfully achieved at one time using designed target. • Al/Ti ratios had no effect on the chemical state of co-doped Ti and Al atoms. • The mechanical and tribological properties were strongly dependent on Ti/Al ratios. • Different friction mechanisms were observed with Al/Ti ratios ranged from 8.8 to 3.0. [ABSTRACT FROM AUTHOR]

Because of their colossal dielectric constant, CaCu3Ti4O12 ceramics have promising applications for cofired multilayer ceramic capacitors. However, their preparation temperature is still too high for such type of applications. This work demonstrates that V2O5 doping can considerably lower the calcination and sintering temperatures of CaCu3Ti4O12 ceramics. Herein, the CaCu3Ti4O12 ceramics, partially substituted by V5+ for Ti4+ with a molecular formula of CaCu3Ti4−xVxO12 (x = 0, 0.01, 0.03, 0.05), were prepared by the solid state reaction method using V2O5 as the doping substance. It has been shown that V2O5 can considerably lower the calcination and sintering temperatures to 870 and 950 °C, respectively. The dielectric constant of the low temperature prepared CaCu3Ti4−xVxO12 ceramics is much larger than the undoped CaCu3Ti4O12. This work provides a preliminary step for possible commercial applications of CaCu3Ti4O12 ceramics for cofired multilayer ceramic capacitors. [ABSTRACT FROM AUTHOR]

Bi0.8Gd0.2Fe0.95Ti0.05O3 (BGFT) multiferroic ceramics were prepared by a solid-state reaction, and their sintering, microstructure, dielectric and magnetic properties were studied. Experimental results show that BGFT ceramics sintered at 980 °C possess a pure orthorhombic (space group, Pnma) structure, and these ceramics possess high relative theoretical density (∼95%), low leakage current density (10−6 A/cm2). The magnetic and electric measurements show the coexistence of ferroelectric and weak ferromagnetic in BGFT ceramics. The results of the Rietveld refinement for BGFT ceramics reveal the existence of bismuth and oxygen vacancies, and these vacancies have an important influence on the electric and magnetic properties. [ABSTRACT FROM AUTHOR]

In this work, Cu-containing diamond-like carbon (Cu-DLC) films were deposited using a hybrid system combining an anode-layer ion beam carbon source and DC magnetron sputtering, where the Cu content in range of 1.0– 67.7 at.% was controlled by varying sputtering current. The effect of Cu content on the electrical and piezoresistive behavior of films was investigated. Increasing the Cu content from 1.0 to 67.7 at.% enhanced the conductive sp2 phases and caused the more Cu nanoparticulates dispersed uniformly in the insulate sp3 amorphous matrix, which significantly reduced the gauge factor from 5.6 to 1.4. Meantime, the temperature coefficient of resistance demonstrated the increase from −3646 to +294 ppm/K with increasing the temperature from 100 to 350 K, indicating the electrical properties were dominated from typical semiconductor to metal-like behavior. Particularly, increasing Cu content from 20.6 to 67.7 at.% led to the threshold voltage being identified and gradually decreasing. The electrical and piezoresistive behavior of the Cu-DLC films was discussed in terms of the carrier tunneling process between conductive phases distributed in amorphous sp3 matrix. [Display omitted] • Cu-DLC nanocomposite films were deposited by the hybrid plasma process. • Piezoresistive properties and electrical behavior of Cu-DLC films were studied. • Gauge factor was strongly related with content and nanoparticulates size of Cu. • Increasing content of Cu led to transition from tunneling to percolation model. [ABSTRACT FROM AUTHOR]

High-power direct laser deposition (HP DLD) was utilized to fast generate AISI 316L stainless steel parts with large size and excellent mechanical properties. In order to efficiently manufacture the stainless steel parts with high surface quality and dimensional accuracy, a dry milling finish was applied. During the DLD process, heat retaining powder was employed to prevent buckling deformation. The effect of building direction on the microstructure, mechanical properties and machinability of the stainless steel was investigated. It was found that the microstructure was homogeneous, at the building direction of 0°, while a number of larger dendritic grains were present in the microstructure, at the building direction of 90°. The tensile properties and hardness values at the building direction of 0° were higher than those at the building direction of 90°. For both building directions, the decrement in surface roughness and the increment in cutting force and tool wear, were observed with the increase in cutting speed. The cutting force, tool wear and surface roughness of the additive manufactured stainless steel at the building direction of 0° were relatively higher, which implies that the anisotropy in the machinability could be utilized to increase efficiency and reduce production cost. [ABSTRACT FROM AUTHOR]

Lightweight Al 2 NbTi 3 V 2 Zr alloy was fabricated through mechanical milling and vacuum hot pressing. The effects of milling on the microstructure, phase evolution, and hardness of the fabricated alloy were investigated. High-energy (HE) milling decreased the size of crystalline grains and activated the powders for subsequent sintering. HE-annealed powders at above 900 °C and all sintered bulks consisted of body-centered cubic (BCC) and intermetallics α and β. Low-energy (LE) milling only provided homogeneity to the powders. LE bulks exhibited a microstructure similar to that of HE bulks at 1450 °C–1550 °C. The hardness of the HE bulk was higher than that of the LE bulk and exhibited a peak value of 781 HV at 1250 °C. All Al 2 NbTi 3 V 2 Zr bulks possessed low density ranging from 5.05 g/cm 3 to 5.25 g/cm 3 . Two empirical equations for hardness of the bulks were proposed for the BCC matrix bulks and simple cubic matrix bulks respectively and the estimated results are consistent with the experimental measurements. [ABSTRACT FROM AUTHOR]

By choosing carbide-forming element Cr and non-carbide-forming element Cu as co-doped metal elements, we firstly fabricated Cu and Cr co-doped diamond-like carbon (Cu/Cr-DLC) films using a facile hybrid ion beam deposition system. The effect of Cu/Cr co-doping on wettability and mechanical properties of DLC films were focused. The resultant Cu/Cr-DLC films were shown to afford good hydrophobicity and superior mechanical performance. In particular, the film with Cu 11.88% Cr 6.57% (at.%) exhibited a relatively high water contact angle of 103.6°, lower residual stress of 0.89 GPa and high hardness of 13.44 GPa. The combined structural analysis demonstrated that the synergistic Cu/Cr co-doping resulted in the critical and significant relaxation of distorted C C bond length, which ultimately caused the reduction in residual stress. Due to the formation of hard Cr carbide nano-particles in amorphous carbon matrix, the films maintained the high value of hardness. In addition, noted that the interesting wetting variety from hydrophilic to hydrophobic state was attributed to the enhanced surface graphitization and emergence of copper oxidation phases, and the film topographical microstructure could also promote the hydrophobicity of film when the maximum height of roughness was in a certain range. These results provide an expected robust synthesis method to make DLC film a promising protective coating for long lasting hydrophobic application and related harsh fields. [ABSTRACT FROM AUTHOR]

Long-term lubricate coatings over a wide temperature range are prerequisite and still facing open challenge for aero-engines and sliding components in harsh conditions. In this work, DC magnetron sputtered VAlN hard ceramic coating was modified by the subsequently post-annealing treatment with graphite powder, where the intermittent amorphous carbon (a-C) top-layer was achieved under temperature of 800 °C and high vacuum. The tribological behavior of modified VAlN coatings was investigated and the results showed that displayed the high hardness of 34.4 GPa and the excellent self-adaptive lubrication from room temperature to 600 °C. Especially, due to the benefits of lamellar sliding interface between a-C top-layer and the a-C transfer film (30 nm–68 nm), the modified coating behaved the lowest friction coefficient of 0.11 at 300 °C. However, increasing the temperature to 600 °C led to the increased and stabilized friction coefficient at 0.36–0.41, which could be attributed to the formation of V 2 O 5 lubricating phase. Further insight into the tribological behavior of the modified VAlN coating by a-C top-layer was discussed in terms of the microstructure evolution during friction test. [ABSTRACT FROM AUTHOR]

Abstract: The present research highlighted the interfacial interaction between modified multiwalled carbon nanotubes (MWCNTs) and epoxy systemically. Stress–strain behaviors of MWCNTs/epoxy composites derived from tensile tests were discussed. The relationship among the morphology, microstructure of the composite interface and its mechanical properties were investigated by scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD). It was found that MWCNTs with necking ends performed significant roles as reinforcing fillers through investigating stress–strain curves and their corresponding HRTEM images. Moreover, compared the microstructure of modified MWCNTs with the original, it was suggested that the modified MWCNTs with disordered outer and integrated inner layers structure are the main parts in absorbing the load and possess a good interfacial adhesion. The preliminary mechanism on performance of interface interaction was proposed in the form of a simplified schematic diagram describing the process of tensile test. [Copyright &y& Elsevier]

The AlCrMoZrTi/(AlCrMoZrTi)N multilayer high-entropy nitride ceramic films (HENCFs) fabricated by reactive RF magnetron sputtering presented (200) preferentially oriented FCC crystal structures. With the increase in the modulation period, the nitrogen content and surface roughness of the multilayer films gradually increased, the template effect between the nanocrystalline and amorphous forms was weakened, and the multilayer interface structure decreased. The S4 film with a modulation period of 1500 nm had the highest hardness and modulus (16.6 and 225.7 GPa, respectively) and the highest H/E* and H3/E*2 values. The results of friction experiments showed that the S1 film with the smallest modulation period had a stable friction coefficient and small wear rate on both Si and Cu substrates, and it exhibited the best friction and wear performance due to its low surface roughness, high toughness and compressive yield resistance, and dense multilayer structure. The friction mechanisms of the HECNFs on Si and Cu substrates were mainly adhesive wear, abrasive wear, and a small amount of oxidative wear. [ABSTRACT FROM AUTHOR]

V-containing solid solution was considered as a promising way to improve the mechanical and tribological properties of hard coatings due to the mechanism of solid solution as well as the induced V-based Magnéli lubricant during friction process. In this work, Cr-V-N coatings with different V contents were prepared on polished cemented carbide and P-type Si (100) wafers by cathodic arc evaporation. The microstructure, mechanical and tribological properties of the coatings with varied V content were discussed. When the content ranged from 0.32 to 31.14 at.%, V entered into the lattice of CrN crystal in the form of solid solution without affecting the coating's phase composition. CrN phase with (111) orientation was formed for all Cr-V-N coatings, and the coating with 31.14 at.% V content showed the weakest crystallinity. The introduction of V still retained the composited coatings with high toughness and excellent adhesion strength of around 100 N on cemented carbide substrates. The maximum elastic modulus and hardness reached up to 438.5 ± 5.3 GPa and 20.0 ± 1.0 GPa, respectively, with V content at 16.55 at.%. Tribological tests at room temperature demonstrated that the friction coefficient of Cr-V-N coatings was relatively low, which was between 0.26 and 0.36. The wear rate was in the order of magnitude of 10−7 mm3N−1 m−1, and the lowest wear rate was 2.5 × 10−7 mm3N−1 m−1 with V content at 0.32 at.%. The friction coefficient and wear rate both increased with the increase of V content. The wear rate of the coatings with high V content (31.14 at.%) was almost four times higher than that of low V content (0.32 at.%) coatings. • An excess of V content altered the way the coating grows. • Solid solution strengthening conferred good mechanical and frictional properties. • The surface roughness and crystallinity influenced the friction coefficient. • Limited tribo-chemical reaction restricted the improvement of friction performance. [ABSTRACT FROM AUTHOR]

• GAD of ta-C was realized by adjusting the filtered incident carbon ions. • GAD benefited a notable reduction of residual stress without distinct hardness loss. • The superior corrosion resistance of ta-C was obtained at glancing angle of 45°. • High sp3 content and enhanced hydrophobicity contributed to anti-corrosion. Tetrahedral amorphous carbon (ta-C) films were obliquely deposited on silicon substrate using a custom-made 45 degree double-bent filtered cathodic vacuum arc (FCVA) system. The effect of glancing angle in a range of 0° to 75° on the growth characteristics, mechanical and electrochemical corrosion behavior of the films were focused. Results showed that increasing the incident angle of carbon ions resulted in a rough surface with agglomerated particles. As the glancing angle changed from 0° to 75°, the residual stress of ta-C film decreased by 28.8%, while the high hardness exceeding 30 GPa were maintained in the films due to the small reduction (13.6%) of sp3 hybridized carbon content. The electrochemical corrosion tests in 3.5 wt% NaCl solution revealed that the superior corrosion resistances were obtained at glancing angle of 45°, which could be discussed in terms of the relatively high sp3 bonded carbon content and the enhanced hydrophobicity properties of the films. [ABSTRACT FROM AUTHOR]

The relationship between microstructure and flow behaviour has attracted attention from many researchers for the past decades, whilst the influences of dislocation and recrystallization on flow stress have not been well understood, which led to failure in flow stress prediction at high temperature compressions. In this work, we tried to provide a novel explanation of the relationship between microstructure evolutions and flow behaviour, and the influence of dislocation and recrystallization on flow stress was investigated. A dislocation based flow stress model was proposed and applied for 300M steel at the strain rate of 0.01–10 s−1 and the temperature of 950–1150 °C. Results showed the established model could predict the flow stress both at constant strain rate conditions and at variable strain rate conditions. The present investigation is helpful to a better understanding of hardening and softening mechanisms in hot compression of 300M steel. [ABSTRACT FROM AUTHOR]

The influence of deposition temperature in the range of 100 °C to 400 °C on the microstructure and mechanical properties of CrB 2 coatings by DC magnetron sputtering was studied. The coating texture changed from random mixed orientation with (101) and (001) planes to the preferred (001) orientation when increasing the deposition temperature. Moreover, the microstructure coating evolved from an underdense structure to a bulky columnar structure (~ 50 nm), and finally to a dense nanoscale columnar structure (~ 7 nm). This structural densification was mainly attributed to the enhanced atomic surface diffusion with increasing deposition temperature. It resulted in promotion of the (001) preferred orientation and greatly enhanced the mechanical properties. Specifically, when the deposition temperature was 300 °C, the CrB 2 coatings exhibited the highest toughness while superhardness (51 ± 2 GPa) was achieved for coating grown at 400 °C. [ABSTRACT FROM AUTHOR]

TiAl intermetallic was vacuum brazed to GH3030 alloy with a Ti-based amorphous filler metal (Ti 33.3 Zr 16.7 Cu 39 Ni 11 , at.%). The effect of the brazing temperature on the microstructural evolution and mechanical properties of the brazed joints was investigated. Ti 3 Al and Al(Cu, Ni) 2 Ti phases composed the diffusion zone I at the TiAl side resulting from the diffusion of Cu and Ni into TiAl intermetallic, and the diffusion zone III at GH3030 side consisted of α-Ni and α-Cr solid-solution phases and a TiNi 3 intermetallic phase, which rooted in the diffusion of Ti into GH3030 alloy. Increasing the brazing temperature accelerated the diffusion and migration of the constituents, and further thickened all reaction zones. The growth rate of zones I and III was w zoneI = 0.0789 μm/oC and w zoneIII = 0.0833 μm/oC, respectively. The formation of zone III was more difficult than that of zone I with the growth activation energy (Q) of Q zoneI = 101.96 kJ·mol−1 and Q zoneIII = 165.58 kJ mol−1. The maximum shear strength was 260 MPa obtained at 960 °C/10 min. All brazed joints fractured at the interface of Al 3 (Cu, Ni)Ti 2 /Al(Cu, Ni) 2 Ti, because of the mismatch of their lattice structure and hardness, and all failed joints demonstrated zonal and brittle features. • The formation mechanism of two solid-state diffusion zones was discussed. • The brazed joint failed along Al 3 (Cu, Ni)Ti 2 /Al(Cu, Ni) 2 Ti phases interface. • Lattice structure, hardness and modulus at the failed interface were discussed. • The maximum shear strength of 260 MPa was obtained at 960 °C/10 min. [ABSTRACT FROM AUTHOR]

Friction stir processing caused obvious grain refinement and texture modification for the experimental AZ31 magnesium alloy. The microstructure, texture as well as mechanical properties were tested for samples cut at different depths from the processed surface of the work-pieces. The micro-hardness in the stir zone was improved to varying extent at different depth. The top layer showed the highest value due to the high density of dislocations. The tensile properties were improved significantly due to the microstructure and texture modification. The texture was weakened in the stir zone, which led to a lower yielding strength and a higher elongation due to the easier activation for basal slip. The true stress-strain curves could be divided into five stages depending on different strain hardening mechanisms, including twinning and dislocation slip. Conventional Hollomon equation was used to describe dislocation related plastic deformation stage while a corrected Arrhenius equation was successfully applied to describe twinning dominated stage. • Microstructure, texture and mechanical properties in different zone were studied. • Inhomogeneous microstructure and texture induced great difference in tensile test. • Samples in the stir zone showed five stages during the tensile test. • Hollomon and Arrhenius equations were used to describe the tensile deformation. [ABSTRACT FROM AUTHOR]

Bi0.8Gd0.2Fe0.95Ti0.05O3 (BGFT) multiferroic ceramics were prepared by a solid-state reaction, and their sintering, microstructure, dielectric and magnetic properties were studied. Experimental results show that BGFT ceramics sintered at 980 °C possess a pure orthorhombic (space group, Pnma) structure, and these ceramics possess high relative theoretical density (∼95%), low leakage current density (10−6 A/cm2). The magnetic and electric measurements show the coexistence of ferroelectric and weak ferromagnetic in BGFT ceramics. The results of the Rietveld refinement for BGFT ceramics reveal the existence of bismuth and oxygen vacancies, and these vacancies have an important influence on the electric and magnetic properties. [ABSTRACT FROM AUTHOR]

DLC films with weak carbide former Al and carbide former Cr co-doping (Al:Cr-DLC) were deposited by a hybrid beams system comprising an anode-layer linear ion beam source (LIS) and high power impulse magnetron sputtering using a gas mixture of C 2 H 2 and Ar as the precursor. The doped Al and Cr contents were controlled via adjusting the C 2 H 2 fraction in the gas mixture. The composition, microstructure, compressive stress, mechanical properties and tribological behaviors of the Al:Cr-DLC films were researched carefully using X-ray photoelectron spectroscopy, transmission electron microscopy, Raman spectroscopy, stress-tester, nanoindentation and ball-on-plate tribometer as function of the C 2 H 2 fraction. The results show that the Al and Cr contents in the films increased continuously as the C 2 H 2 fraction decreased. The doped Cr atoms preferred to bond with the carbon while the Al atoms mainly existed in metallic state. Structure modulation with alternate multilayer consisted of Al-poor DLC layer and Al-rich DLC layer was found in the films. Those periodic Al-rich DLC layers can effectively release the residual stress of the films. On the other hand, the formation of the carbide component due to Cr incorporation can help to increase the film hardness. Accordingly, the residual stress of the DLC films can be reduced without sacrificing the film hardness though co-doping Al and Cr atoms. Furthermore, it was found that the periodic Al-rich layer can greatly improve the elastic resilience of the DLC films and thus decreases the film friction coefficient and wear rate significantly. However, the existence of the carbide component would cause abrasive wear and thus deteriorate the wear performance of the films. [ABSTRACT FROM AUTHOR]

Self-diffusion gradient cermet composite tool materials with different characteristics of surface layer were prepared by a vacuum hot-pressing sintering technology at 1475 °C for 30 min under 32 MPa. A subsurface layer was formed automatically by a self-diffusion driving force during sintering. The evolutions of microstructure and elements distribution were investigated, and the effects of vanadium carbide (VC) content and surface layer thickness on microstructure and mechanical properties were discussed. The results showed that the Co, Ni and N elements were redistributed and formed a subsurface layer gradient zone. N element diffused toward the surface layer, while Co and Ni metal binder were abundant in the subsurface layer. The density and mechanical properties were improved by the addition of VC in the surface layer. The flexural strength, substrate hardness and surface hardness of the self-diffusion gradient composite with a surface layer thickness of 230 µm were 1198±135 MPa, 23.68±0.68 GPa and 28.22±0.87 GPa, respectively, when 4 mass% VC was used. [ABSTRACT FROM AUTHOR]

• A novel method to obtain in-situ TiN reinforced composite coatings. • N 2 as transport gas provides N source for the in-situ synthesis of TiN particles. • The interface between TiN and Ti matrix formed an almost perfect coherent interface. • The wear loss of the composite coating was reduced by 85.9% compared with Ti6Al4V. In-situ TiN reinforced composite coatings were prepared on Ti6Al4V by plasma spray welding with nitrogen as the transport gas. TiN particles were in-situ synthesized by the reaction of Ti and nitrogen. The composite coatings were characterized by in-situ TiN particles embedded in Ti matrix. The interface between them was clean and smooth. In addition, due to the 13°6′ difference in crystal orientation and the close interplanar spacing, the two crystals could form an almost perfect coherent interface that was beneficial to the performance improvement of the composite coatings. Compared with Ti6Al4V, the microhardness and abrasive resistance of the composite coatings were obviously enhanced mainly because of the existence of in-situ TiN particles. [ABSTRACT FROM AUTHOR]