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The effect of Ru addition on the martensitic transformation and mechanical properties of Zr50Pd50−xRux SMAs shape memory alloys has been studied. Strain–temperature experiments, differential scanning calorimeter, and scanning electron microscope analyses were performed to validate the theoretical predictions by DFT calculation regarding the influence of the C′ parameter on martensitic stability. Despite the absence of an observed shape memory effect under the tested conditions, the findings suggest that ZrPdRu alloys hold promise for high-temperature applications. [ABSTRACT FROM AUTHOR]

Using the tin alloy module in the material phase diagram and thermodynamic simulation software JMatPro, the phase compositions of different components of Sn-Bi-Pb low melting point alloys with the same Sn content were simulated based on the phase diagrams of Sn-Bi, Sn-Pb, and Pb-Bi binary alloys, and the influence of alloying element content on the melting characteristics of the alloys was investigated, which was used for the optimization of the components and the obtaining of low melting point alloys with excellent melting characteristics. The microstructure and melting characteristics of the optimized alloys were characterized by Scanning electron microscope (SEM), Thermogravimetry Analysis-Differential Scanning Calorimetry (TG-DSC), X-ray diffractometer (XRD), etc., and the influence of phase content on the mechanical properties was investigated. The results show that the Sn-Bi-Pb alloy possesses Sn-(Bi, Pb) phase, Bi-(Pb) phase and Pb7Bi3 intermetallic compound phase, and the simultaneous increase of the Bi element and decrease of the Pb element content to the Sn-Bi-Pb alloy obviously improves its tensile strength, but the elongation rate shows a decreasing trend, among which Sn50Bi30Pb has the optimal comprehensive performance, with a tensile strength of 38.60 MPa, an elongation of 61.13%, and a melting range of 94.0℃~100.6℃. [ABSTRACT FROM AUTHOR]

Considering the high demand for innovative solutions in medicine, a major increase in interest in biomaterials research has been noticed, with the most significant advancements in metals and their alloys. Titanium-based alloys are one of the most recognised in the scientific community but do not represent the only way to achieve optimal results. Zirconium alloys for medical applications are a novelty with significant research potential based on their outstanding properties, which may be of value for medicine. The aim of the present study was to obtain new biomedical Zr-Nb-Mo alloys with varying ratios of their respective elements—Zr and Mo—using combined powder metallurgy (PM) and arc melting (VAM) methods. The obtained samples underwent microstructure analysis using an optical microscope (OM) and a scanning electron microscope (SEM). The study of element distribution was conducted with energy dispersive spectroscopy (EDS), whereas the phase composition was determined using X-ray diffraction (XRD). Mechanical properties were examined with a Micro Combi Tester MCT3, whereas tribological properties were assessed with a TRN Tribometer, and Ringer's solution was used as a lubricant. Additionally, the wear tracks of the studied samples were observed using the SEM. The research results indicated that increased Mo content conduced to microstructure refinement and homogeneity. Furthermore, the higher content of this element contributed to the growth of the HVIT, HIT, and EIT parameters, together with the improvement in the tribological performance of the alloys. XRD analysis revealed that the obtained samples were multiphase, and raising the Mo addition promoted the formation of new phases, including a ternary phase—Zr0.9Nb0.66Mo1.44 (Fd 3 ¯ m). The chemical composition study showed uneven distribution of niobium and areas of uneven mutual distribution of zirconium and molybdenum. [ABSTRACT FROM AUTHOR]

Titanium alloys have broad application prospects in the field of marine engineering due to their excellent corrosion resistance and comprehensive mechanical properties. Titanium alloys, when connected with other metals, such as copper-nickel alloys, could produce two distinct effects. On the one hand, the passive film gives titanium alloys positive potential, which could accelerate galvanic corrosion of negative-potential metals. On the other hand, the passive film could obstruct current flow and prevent further development of galvanic corrosion. In this paper, Potentiodynamic Polarization, Electrochemical Impedance Spectroscopy, and Electrochemical Noise techniques were utilized to investigate the galvanic corrosion behavior of B10/Ti80 under simulated seawater environment. The corrosion morphology and product composition were studied using Scanning Electron Microscope and X-ray Photoelectron Spectroscopy. The above experimental results showed that Ti80 and B10 served as the anode and cathode respectively in the early stages of corrosion (within 2.5 h of immersion), due to the incomplete formation of the passivation film on Ti80. While in the latter stages of corrosion, due to the positive shift of Ti80's potential by passivation, there was a noticeable accelerated corrosion effect on B10, which was proportional to the area ratio of Ti80/B10 and showed a gradually stable trend after 28 days of immersion in the seawater. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to investigate the effect of coating time on the formation of hydroxyapatite (HA) coating layer on ZK60 substrate and understand the biodegradation behavior of the coated alloy for biodegradable implant applications. Methods: Biodegradable ZK60 alloy was coated by HA layer for different times of 0.5, 1, 2, and 4 h by chemical conversion method. After coating, all the coated specimens were used for immersion test in Hanks' solution to understand the effect of coating time on the degradation behavior of the alloy. The degradation rate of the coated alloy was evaluated by Mg2+ ion quantification and pH change during immersion test. The microstructure of the coating layer was examined by scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectroscopy (EDS) before and after immersion to understand the degradation behavior of the coated alloy. Results: HA coating layers were formed successfully on surface of ZK60 specimens after 0.5, 1, 2, and 4 h with different microstructure. Optimal coating quality was observed at 1 or 2 h, characterized by well-formed and uniform HA layers. However, extending the coating duration to 4 h led to the formation of cracks within the HA layer, accompanied by Mg(OH)2. Specimens coated for 1 and 2 h exhibited the lowest degradation rates, while specimens coated for 0.5 and 4 h showed the highest degradation rates. Furthermore, analysis of degradation products revealed the predominance of calcium phosphates formed on the surface of specimens coated for 1 and 2 h. Conversely, specimens coated for 0.5 and 4 h exhibited Mg(OH)2 as the primary degradation product, suggesting a less effective corrosion barrier under these conditions. Conclusion: The HA layer formed after 2 h demonstrated as the most effective coating layer for enhancing the corrosion resistance of the ZK60 alloy for biomedical applications. [ABSTRACT FROM AUTHOR]

This paper reports the results of our study on electrochemical polishing of titanium and a Ti-based alloy using non-aqueous electrolyte. It was shown that electropolishing ensured the removal of surface defects, thereby providing surface smoothing and decreasing surface roughness. The research was conducted using samples made of titanium and Ti6Al4V alloy, as well as implant system elements: implant analog, multiunit, and healing screw. Electropolishing was carried out under a constant voltage (10–15 V) with a specified current density. The electrolyte used contained methanol and sulfuric acid. The modified surface was subjected to a thorough analysis regarding its surface morphology, chemical composition, and physicochemical properties. Scanning electron microscope images and profilometer tests of roughness confirmed significantly smoother surfaces after electropolishing. The surface profile analysis of processed samples also yielded satisfactory results, showing less imperfections than before modification. The EDX spectra showed that electropolishing does not have significant influence on the chemical composition of the samples. [ABSTRACT FROM AUTHOR]

In this paper, the microstructure and mechanical properties of Al-6.5Si-5.5Cu-0.2Zr-0.01Sr-0.06Ti-0.2Ce cast aluminum alloys were investigated in multistage solid solution systems. The microstructure of the alloy was characterized using an optical microscope (OM), scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), x-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. The hardness and conductivity of the alloy were measured using a Vickers hardness and eddy current conductivity testers, respectively, and the tensile properties were described by a drawing machine. The results showed that the mechanical properties of the alloy are the worst under the four-stage solid solution system (G1). With the increase in multistage solution temperature and holding time, θ phase (Al2Cu) was gradually dissolved into α-Al matrix to enhance the effect of dislocation strengthening. When the solution temperature reached 510 °C, the mechanical properties of the alloy were the best, and the tensile strength and elongation were increased to 354.90 MPa and 9.02%, respectively. With the increase in temperature, eutectic Si agglomeration and large area of insoluble phase between metals were found, resulting in the decrease in mechanical properties. [ABSTRACT FROM AUTHOR]

Magnesium and its alloys are advantageous in clinical applications due to their excellent mechanical properties and suitable biological properties. However, due to their high corrosion rate in physiological environments, these alloys' application was limited. Polypyrrole (PPy) coatings were potentiostatically deposited on AZ31 alloy to reduce its corrosion rate in this study. The effect of applied potential and monomer concentration on the coatings' characteristics and properties such as wettability, corrosion resistance, and adhesion strength was studied. The coatings had cauliflower and porous micro-granular morphologies, according to scanning electron microscope images. The thickness and average roughness of the coatings increased from 0.3 to 3.8 µm and 18.3 to 43.7 nm, respectively, as the monomer concentration in the deposition bath was increased from 0.1 to 0.2 M. Increasing the applied potential had the same effect on thickness and roughness. According to the water contact angle (WCA) results, the alloy and all of the PPy coatings were hydrophilic. However, increasing the monomer concentration of the bath and the applied potential increased the WCA of the coatings. The electrochemical behavior of the samples in Ringer's solution was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy. All of the coatings outperformed the bare substrate in terms of corrosion resistance. The corrosion current density of the optimum PPy coating obtained from a bath with 0.2 M pyrrole monomer at 3 V was approximately seven times lower than that of the AZ31 alloy. In the cross-cut adhesion test, this coating also demonstrated the best adhesion to the substrate. [ABSTRACT FROM AUTHOR]

Because of their high mixing entropies, multi-component alloys can exhibit enhanced catalytic activity compared to traditional catalysts in various chemical reactions, including hydrogenation, oxidation, and reduction processes. In this work, new AgCoCuFeNi high entropy alloy nanoparticles were synthesized by the hydrogen reduction-assisted ultrasonic spray pyrolysis method. The aim was to investigate the effects of processing parameters (reaction temperature, precursor solution concentration, and residence time) on the microstructure, composition, and crystallinity of the high entropy alloy nanoparticles. The characterization was performed with scanning electron microscope, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The syntheses performed at 600, 700, 800, and 900 °C, resulted in smaller and smoother spherical particles with a near-equiatomic elemental composition as the temperature increased to 900 °C. With 0.25, 0.1, and 0.05 M precursor solutions, narrower size distribution and uniform AgCoCuFeNi nanoparticles were produced by reducing the solution concentration to 0.05 M. A near-equiatomic elemental composition was only obtained at 0.25 and 0.05 M. Increasing the residence time from 5.3 to 23.8 s resulted in an unclear particle microstructure. None of the five metal elements were formed in the large tubular reactor. X-ray diffraction revealed that various crystal phase structures were obtained in the synthesized AgCoCuFeNi particles. [ABSTRACT FROM AUTHOR]

To perform quality assessments of both metal alloys and many other engineering materials, measurements of the volume fractions of phases or microstructure components are utilized. For this purpose, quantitative analysis of the evaluated components' distribution on metallographic specimens is often employed. Phases or components of the microstructure are identified based on the variation in signal received in the band of light seen. Problems with the correct identification of measurement results in this spectral band can be caused by the inhomogeneity of the etching when the alloy components are segregated. Additional uncertainty arises when the analyzed image pixel contains a boundary between grains of different phases. This article attempts to use the results of local chemical composition measurements as a source signal for quantitative evaluation of phase composition. For this purpose, quantitative maps of elemental concentration distributions, obtained with a Tescan Mira GMU high-resolution scanning electron microscope in QuantMap mode, were used as input data for the phase composition evaluation of an EN AC 46000 alloy sample. The X-ray microanalysis signal generation area may contain grains of more than one phase. Therefore, evaluation of the phase fractions in areas of individual measurements were calculated by looking for the minimum of the objective function, calculated as the sum of the squares of the deviations of the results of measurements of the concentration of individual elements from the weighted average values of solubilities of these elements in the phases. [ABSTRACT FROM AUTHOR]

The FurnaSEM microfurnace was installed in the chamber of a scanning electron microscope to carry out in situ experiments at high temperatures and test its limits. The microfurnace was used in combination with different types of detectors (Everhart–Thornley for the collection of secondary electrons in a high vacuum, gas secondary electron detector for the specific collection of secondary electrons in the presence of gas, and Karmen© detector for the collection of backscattered electrons at high temperature). Experiments carried out on various samples (metal alloys and ceramics) show that the microfurnace operates in both high-vacuum and low-vacuum modes. Temperature ramp rates during temperature cycles applied to the sample range from 1 to 120 °C/min (temperature rise) and 1 to 480 °C/min (controlled and natural cooling). The maximum temperature at which images were recorded up to 25 k × magnification was 1340 °C, with a residual air atmosphere of 120 Pa. The choice of a flat furnace with the sample placed directly above it has enabled innovative experiments to be carried out, such as low-voltage imaging (using a shorter working distance—up to 10 mm—than is possible with conventional furnaces), 3D imaging (by tilting the stage by up to 10°), and high-temperature backscattered electron imaging (using a dedicated detector). [ABSTRACT FROM AUTHOR]

Weight reduction is one of the prime goals for auto industries to achieve fuel economy, and magnesium matrix composite offers the opportunity to assist with fulfilling those needs. The present work focuses on developing the magnesium alloy (AZ91D), AZ91D/SiCnp nanocomposite, and AZ91D/SiCnp/CNT hybrid nanocomposite via the semisolid stir casting technique incorporating the ultrasonic vibration process. The produced cast samples are subjected to physical, microstructural, and mechanical characteristics study. The evaluated results are compared and it was found that AZ91D/6wt% SiCnpnanocomposite offers high hardness (78.45 ± 0.1 Hv), yield (150 ± 1.8 MPa), and ultimate tensile strength (241 ± 1.75 MPa) as compared to the cast AZ91D alloy samples. The scanning electron microscope reveals the homogeneous particle distribution structure with reduced porosity. The density of the developed composite obeys the rule of the mixture, and the porosity is limited to less than 1%. The presence of 6 wt% carbon nanotube in AZ91D/6wt% SiCnp alloy nanocomposite facilitates superior hardness, yield, and tensile strength of 84.35 ± 0.1 Hv, 174 ± 1.5 MPa, and 271 ± 1.6 MPa. The impact strength of the composite increased, while the content of SiCnp was improved. [ABSTRACT FROM AUTHOR]

This project studies the influence of different grain sizes of Ni-based Fe-33Ni-19Cr alloy obtained from heat treatment procedure on high temperature isothermal oxidation. Heat treatment procedure was carried out at two different temperatures, namely 1000°C and 1200°C for 3 hours of soaking time, followed by quenching in the water. These samples are denoted as T1000 and T1200. The heat-treated Ni-based Fe-33Ni-19Cr alloy was subjected to an isothermal oxidation test at 950°C for 150 hours exposure. Oxidized heat-treated alloys were tested in terms of oxidation kinetics, phase analysis and surface morphology of oxidized samples. Oxidation kinetics were determine based on weight change per surface area as a function of exposure time. Phase analysis was determined using the x-ray diffraction (XRD) technique and surface morphology of oxidized samples was characterized using a scanning electron microscope (SEM). As a result, the heat treatment procedure shows varying grain sizes. The higher the heat treatment temperature, shows an increase in grain size with a decrease in hardness value. The oxidation kinetics for both heat-treated samples showed an increment pattern of weight change and followed a parabolic rate law. The oxidized T1000 sample recorded the lowest parabolic rate constant of 3.12×10-8 mg2cm-4s-1, indicating a low oxidation rate, thus having good oxidation resistance. Phase analysis from the XRD technique recorded several oxide phases consisting of Cr2O3, MnCr2O4, and (Ti0.97Cr0.03)O2 oxide phases. In addition, a uniform oxide layer is formed on the oxidized T1000 sample, indicating good oxide scale adhesion, thereby improving the protective oxide behavior. [ABSTRACT FROM AUTHOR]

Thin-walled Al-Mg-Si alloy profiles with different compositions and aging states were prepared using the heating and extrusion process. The properties and structure of the profiles were then investigated using a metallographic microscope, scanning electron microscope, projection electron microscope, and universal testing machine. The results show that the yield strength and tensile strength of the profile increases with the increase in total Mg + Si content, and ductility is reduced. If the total Mg + Si content is too high or too low, the crush performance of the material would decrease. Compared with the under-aged and near-peak-aged states, the three types of AI-Mg-Si alloy thin-walled profiles at the over-aged state have better effective energy absorption during crushing and higher bending angle; however, the tensile strength of the profile is optimal at the near-peak-aged state. The effects of alloy composition and aging process on material strength and crushing energy absorption are mainly attributed to the grain structure and differences in precipitation. For coarse grain structures, the grain boundary precipitate free zones are wider, which decreases the profile ductility. Simultaneously, an increase in primary strengthening phases in the grains would increase the profile strength. [ABSTRACT FROM AUTHOR]

Micron‐sized graphite particles additions to Al2011 alloy were investigated to know their impact on mechanical properties. The stir cast method was used to manufacture the Al2011 alloy with 2 and 4 wt% of graphite particles reinforced composites. The microstructural analysis and mechanical properties of the synthesized composites were tested. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) spectrums were used to characterize the microstructure of the samples that were obtained from the casting. SEM micrographs indicated the homogeneous distribution of particles and the EDS patterns confirmed the presence of graphite particles. Al2011 alloy hardness was decreased with the addition of graphite particles. Further, with the addition of 2 and 4 wt% of graphite particles in the Al2011 alloy, the ultimate tensile and yield strengths of composites were increased with increase in elongation. SEM micrographs of tensile fractured surfaces were used to study the various fractured behaviors in the Al2011 alloy‐graphite composites. [ABSTRACT FROM AUTHOR]

This study investigates the new surface development on AA6061 and AA5086 alloys considering the wire-arc additive manufacturing technique as a direct energy deposition (DED) process of wire. Two different quantities of MWCNTs, i.e., 0.01 (low) and 0.02 (high) g, with a constant nickel (Ni) weight (0.2 g) were pre-placed in the created square patterns. ER4043 filler was used as a wire for additive deposition, and an arc was generated through a tungsten inert gas (TIG) welding source. Furthermore, hardness and pin-on-disk wear-testing methods were employed to measure the changes at the surfaces with the abovementioned inducements. This work was designed to illustrate the hardness and the offered wear resistance in terms of mass loss of the AA6061 and AA5086 aluminum alloys with the function of nano-inducements. Two sliding distance values of 500 m and 600 m were selected for the wear analysis of mass loss from tracks. A maximum increase in hardness for AA6061 and AA5086 alloys was observed in the experiments, with average values of 70.76 HRB and 74.86 HRB, respectively, at a high mass content of MWCNTs. Moreover, the tribological performance of the modified surfaces improved with the addition of MWCNTs with Ni particles in a broader sense; the modified surfaces performed exceptionally well for AA5086 compared to AA6061 with 0.02 and 0.01 g additions, respectively. The system reported a maximum of 38.46% improvement in mass loss for the AA5086 alloy with 0.02 g of MWCNTs. Moreover, the morphological analysis of the developed wear tracks and the mechanism involved was carried out using scanning electron microscope (SEM) images. [ABSTRACT FROM AUTHOR]

Due to the poor activation performance and kinetics of Ti50V25Cr25 alloys, the element Zr was added to improve the phase structure of the alloy and achieve a high-performance hydrogen storage alloy. The Ti50−xV25Cr25Zrx (x = 0, 5, 7, and 9) system alloys were prepared by arc melting. The alloys were analyzed using an X-ray diffractometer (XRD), scanning electron microscope (SEM), and differential scanning calorimeter (DSC). The hydrogen storage capabilities of the alloys were also obtained by the Sievert volumetric method. The results indicated that the alloy with Zr added had a combination of the C15 Laves phase and the BCC phase, whereas the Zr-free alloy had a BCC single phase. The partial replacement of Zr with Ti resulted in an increase in the lattice parameters of the main phase. The hydrogen storage kinetic performance and activation of the alloys both significantly improved with an increasing Zr concentration. The time to reach 90% of the maximum hydrogen storage capacity decreased to 2946 s, 230 s, and 120 s, respectively, with the increases in Zr concentration. The initial hydrogen absorption content of the alloys increased and then decreased after the addition of the element Zr. The second phase expanded with an increasing Zr concentration, which in turn decreased the abundance of the BCC main phase. The Ti43V25Cr25Zr7 alloy showed good cycle stability and hydrogen-desorption performance, and it could absorb 90% of the maximum hydrogen storage capacity in around 230 s. The maximum hydrogen-absorption capacity of the alloy was 2.7 wt%. The diffusion activation energy of hydrogen desorption dropped from 102.67 kJ/mol to 92.62 kJ/mol. [ABSTRACT FROM AUTHOR]

To improve the corrosion behavior and discharge performance of Mg–1Sn‐based Mg–air battery anodes, Zn/Ca alloying elements are added in the alloys to modify the type and morphology of the formed second phases. Scanning electron microscope is used to observe the microstructure, and X‐ray diffraction is used to identify the phases formed. Immersion, electrochemistry techniques, and Mg–air battery tests are used to characterize the corrosion and discharge performance of the alloys. The results indicate that the addition of Ca rather than Zn has better effects in improving the corrosion resistance and discharge performance of Mg–1Sn‐based alloys. The second‐phase combination improves the corrosion resistance and electrochemical activity of Mg–1Sn‐based alloys in the following order: Mg2Ca and CaMgSn phases (Mg–1Sn–1Ca alloy) > Ca2Mg6Zn3 and CaMgSn phases (Mg–1Sn–1Zn–1Ca alloy) > the net‐shape Mg4Zn7 + Mg2Sn phases (Mg–1Sn–1Zn alloy) > Mg2Sn phase (Mg–1Sn alloy). In addition, Mg–1Sn–1Zn–1Ca alloy exhibits the highest anodic efficiency, specific capacity, and specific energy among four alloys, i.e., 54.3 , 1197.6 mA h g−1, and 1366.1 mW h g−1, respectively, at a current density of 20 mA cm−2. [ABSTRACT FROM AUTHOR]

In the present paper, microstructural changes in two alloys, IN617 and DMV617 mod, after 5 h and 1000 h of aging at 700 °C were investigated using scanning transmission electron microscopy. The mechanical properties of the samples were evaluated using hardness tests. Precipitates were identified using energy-dispersive X-ray spectroscopy analysis. After long-term aging, intensive precipitation of the M23C6 carbides and γ′ intermetallic phase in the microstructure of alloys was observed. In the IN617 alloy, continuous layers of M23C6 carbides along the grain boundaries after long-term aging were observed. The minor addition of boron to the DMV617 mod alloy is advantageous in microstructure formation during long-term aging because it decreases the agglomeration of M23C6 at the grain boundaries. [ABSTRACT FROM AUTHOR]

The anisotropic damage behavior has a great influence on the formability of rolling sheets. This work aimed to investigate the anisotropic damage mechanism of the LA103Z Mg‐Li alloy rolling sheet by combining mesoscale detection and modeling. The X‐ray computed tomography (XCT) and scanning electron microscope (SEM) were applied to characterize the evolution of damage morphology and volume fraction in RD, DD, and TD directions of the rolling sheet. The GTN damage model was calibrated by the experimental results with the representative volume element (RVE) method. The anisotropic damage mechanism was revealed via experimental and modeling results. The micro void nucleation strain εN was critical to determine the initiation moment of the anisotropic damage. The continuous nucleation in RD direction, the severe growth in DD direction, and the massive coalescence in TD direction were the micro void evolution competition results that caused the anisotropy for damage mechanism and fracture strain. Highlights: The micro void evolution was quantitatively characterized by XCT and SEM methods.The GTN damage model calibrated by the RVE method exhibited accurate prediction.εN was the critical strain for determining the initiation of anisotropic damage.Anisotropic damage was caused by different responses of micro void evolution. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of the element La on plasma nitriding of the CoCrCuFeNi high-entropy alloy (HEA) at 440 °C for 8, 16, and 24 h. The phase composition, morphology, and hardness distribution of the nitrided layer are characterized using XRD, optical microscopy, and a microhardness tester. Furthermore, the corrosion resistance is tested using an electrochemical workstation. The study evaluated the friction and wear performance using a testing machine and scanning electron microscope. The thickness of the effective hardening layer after 16 h of treatment with La was similar to that after 24 h of treatment without La. The addition of La significantly increased the growth rate constant of the effective hardening layer from 0.53 × 10−14 m2/s to 0.72 × 10−14 m2/s. In addition, an expanded FCC phase with greater interplanar spacing can be formed on the surface of the sample by introducing La into the plasma nitriding process. This indicates that the expanded FCC phase, with a higher concentration of interstitial nitrogen atoms, can effectively improve the corrosion resistance of the specimen surface. The corrosion rate of the specimen surface was reduced by 27.5% and the wear rate was reduced by 41.7% after 16 h of treatment with the addition of La compared to 24 h of nitriding without the addition of La. It has been shown that the addition of La to the plasma nitriding process results in a higher quality nitrided layer in a shorter time and also demonstrates that La has the potential to optimize the surface properties of plasma nitrided HEAs. [ABSTRACT FROM AUTHOR]

The paper reports on the atomic investigation about β phase in Mg 96 Gd 2 Y 1 Ni 1 alloy by using the first-principles study and the high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) corrected by atomic Cs. By using HAADF-STEM, the rectangular β phases were observed in the underage and peak aging stages in Mg 96 Gd 2 Y 1 Ni 1 alloy. The β phase could be precipitated from the previously precipitated β phase, and the β phase grew in steps when it was precipitated. A special transition structure of three atomic layer thicknesses was first observed at the edge of the β phase and the structure of this interface is probably as the β/Mg 1 interface for the analysis of thermodynamic characterization and electronic characterization. The β' phase and the β H structure were precipitated only at the edge of the length directions of the β phase. The β' phase continues to grow into a β phase directly without the formation of β 1 phase, resulting in an increase in the length of the β phase, which is discovered for the first time. [ABSTRACT FROM AUTHOR]

In order to improve the corrosion resistance of Mg-3Gd-1Zn-0.4Zr (GZ31K) alloys for biomedical application, the alloy was micro-arc oxidation (MAO)-treated using silicate electrolyte system under various voltages (400 V, 425 V, 450 V, 475 V). The effects of voltage on the microstructure and corrosion properties of MAO coating were investigated via X-ray diffraction (XRD) and a scanning electron microscope (SEM) combined with an energy-dispersive spectrometer (EDS), X-ray photoelectron spectroscope (XPS), and electrochemical experiments. The results showed that, with the increase in voltage, the MAO coatings became thicker and the micropores on the MAO coating increased in diameter. The main phase compositions of the MAO coatings were MgO and Mg2SiO4. Potentiodynamic polarization curve results showed that MAO coatings could enhance corrosion resistances, where the corrosion current density decreased by six orders of magnitude and the corrosion potential of the specimens increased by 300 mV for the voltage of 450 V in the MAO treatment; nevertheless, the corrosion resistance rapidly deteriorated due to the creation of large micropores in the MAO coating, which provide a pathway for corrosive media when the voltage is 475 V. The electrochemical impedance spectroscopy results showed that MAO treatments could increase low-frequency modulus resistance and increase the corrosion resistance of Mg alloys. In addition, MAO-treated GZ31K alloys still exhibited uniform corrosion, which is desirable for biomedical applications. [ABSTRACT FROM AUTHOR]

Aluminum alloys are extensively used to manufacture mechanical components. However, when exposed to alkaline environments, like lubricants, refrigerants, or detergents, they can be corroded, reducing their durability. For this reason, the aim of this study is to investigate the influence of aggressive alkaline solutions (i.e., pH and presence of chlorides) on the corrosion resistance of three aluminum alloys (AA 5083-H111, AA 6082-T6, and AA 7075-T6) with and without anodizing treatments. Open circuit potential (EOCP) and anodic polarization measurements were carried out and typical corrosion parameters such as corrosion current density (icor) and corrosion rate (CR) were determined. Morphology of the corrosion attack and samples microstructure were investigated by scanning electron microscope. Results show that corrosion behavior of the three investigated alloys is influenced by (i) the aggressiveness of the testing environments; (ii) the thickness of the anodizing treatment; (iii) the alloy chemical composition; (iv) the distribution of intermetallic phases in the aluminum matrix. Moreover, three galvanic series have been built also testing other metallic alloys commonly used in mechanical applications, i.e., carbon steel (C40), stainless-steel (AISI 304), and Cu-based alloys (Cu-Ni alloy and CW 617 N, respectively). Results clearly indicate that galvanic series play a fundamental role when it is necessary to select an alloy for a specific environment, highlighting the thermodynamic conditions for corrosion occurrence. On the other hand, kinetic measurements and microstructural studies carried out on the three aluminum alloys stress the importance of the surface treatments and relevant thickness as well as the effect of metal exposure. Future work will involve the study of other surface treatments on aluminum alloys and the evaluation of their corrosion behavior in acidic environments. [ABSTRACT FROM AUTHOR]

The deformation aspects associated with the micro-mechanical properties of the powder laser bed fusion (P-LBF) additively manufactured stainless steel 316L were investigated in the present work. Toward that, micro-pillars were fabricated on different planes of the stainless steel 316L specimen with respect to build direction, and an in situ compression was carried out inside the chamber of the scanning electron microscope (SEM). The results were compared against the compositionally similar stainless steel 316L, which was fabricated by a conventional method, that is, casting. The post-deformed micro-pillars on the both materials were examined by electron microscopy. The P-LBF processed steel exhibits equiaxed as well as elongated grains of different orientation with the characteristics of the melt-pool type arrangements. In contrast, the cast alloy shows typical circular-type grains in the presence of micro-twins. The yield stress and ultimate compressive stress of P-LBF fabricated steel were about 431.02 ± 15.51 − 474.44 ± 23.49 MPa and 547.78 ± 29.58 − 682.59 ± 21.59 MPa, respectively. Whereas for the cast alloy, it was about 322.38 ± 19.78 MPa and 477.11 ± 25.31 MPa, respectively. Thus, the outcome of this study signifies that the AM-processed samples possess higher mechanical properties than conventionally processed alloy of similar composition. Irrespective of the processing method, both specimens exhibit ductile-type deformation, which is typical for metallic alloys. [ABSTRACT FROM AUTHOR]

Aluminum–copper-based alloy has a broad liquidus to solidus temperature range, making it susceptible to the formation defects such as pores and shrinkage pores during the process of solidification. Hence, ultrasonic vibration and squeeze casting can help to refine the microstructure and eliminate the formation of pores. In this paper, we used an optical microscope, scanning electron microscope, transmission electron microscope, differential scanning calorimetry, and thermal analysis to study the ultrasonic treatment (UT) and squeeze casting (SC) on the as-cast and heat-treated microstructure of Al–Cu–Mn alloys. The results show that a significant refinement can be obtained by the compound field compared with that of the individual field. The applied UT time is 30 s and 120 s, respectively. The smallest grain size and the finest Al2Cu particles are observed in the alloy with a treated time of 120 s. This is due to the ultrasonic field breaking the dendrites and promoting the flow of molten Al; squeeze casting increases the cooling rate and stimulates the nucleation temperature of α-Al. The size of the θ′ phase after compound field treatment is smaller because more Cu atoms are dissolved in the Al matrix, so the θ' strengthening phase is finely dispersed in the Al alloy matrix. It is concluded that the compound field of UT and SC is a potentially advantageous process to refine the microstructure of Al alloys. [ABSTRACT FROM AUTHOR]

Purpose: FeNi36 (Invar-36) alloy is widely used in the fabrication of molding tools in aerospace industries but there remains a need to improve its wear and friction performance due to its relatively low hardness. The formation of a heat affected zone (HAZ) on the surface of Invar-36 cut by wire electric discharge machining (WEDM) is promising to enhance its tribological properties. This study aims to investigate the tribological performance of WEDM-treated Invar-36 via a ball-on-disk tribometer in dry-sliding conditions. Design/methodology/approach: The untreated and WEDM-treated Invar-36 surfaces were reciprocated against an alumina ball at a sliding velocity of 40 mm/s, a stroke length of 10 mm and a sliding duration of 125 min under loads of 5, 10 and 20 N. The worn surfaces were characterized using a 2D profilometry and a scanning electron microscope equipped with energy-dispersive spectroscopy. Findings: The results showed that the WEDM-treated surface had a superior friction coefficient and wear resistance in comparison to the untreated surface, due to the grown HAZ. There was found to be a 9.3%–11.4% decrease in the friction coefficient and a 47%–57% reduction in the wear volume after the WEDM treatment. Both the untreated and WEDM-treated Invar-36 surfaces found abrasion and plastic deformation as the dominant wear mechanisms. Originality/value: Previous works have not focused on the tribological performance of the WEDM-treated Invar-36 extensively used for molding tools in aerospace industries. Our findings provide compelling evidence that the WEDM treatment improved the wear and friction performance of Invar-36 alloy because of the grown HAZ. [ABSTRACT FROM AUTHOR]

In this paper, Al0.6CoCrFeNi/5052 aluminum matrix composites were prepared at different sintering temperatures (550–700 °C) by vacuum hot-pressing sintering. The effects of sintering temperature on composites were studied by testing the morphology, phase composition and mechanical properties of the composites, which were characterized by uniaxial compression experiments, X-ray diffraction, scanning electron microscope, electron probe and nanoindentation. The results show that the prepared composites have high strength and very good ductility with sintering temperature lower than 700 °C. When the sintering temperature is above 550 °C, the interface layer is formed in the composite material. As the sintering temperature increases, the formation method of the interface layer changes. The generation of the interface layer has a significant effect on the mechanical properties of the composites. [ABSTRACT FROM AUTHOR]

The Mg-(4-x)Nd-xGd-0.3Sr-0.2Zn-0.4Zr (x = 0, 1, 2, and 3 wt%, Gd/Nd = 0, 1/3, 1, and 3) alloys were hot extruded and then aged (T5). The friction and wear properties of the as-extruded and as-aged alloys were studied using a ball-on-disk wear testing machine and a scanning electron microscope to reveal the impacts of the Gd/Nd ratio and aging treatment. The results show that the friction coefficient of the as-extruded alloys increases first and then decreases with increasing Gd/Nd ratio. After aging, the friction coefficient of the alloys decreases slightly. The Gd/Nd ratio has no significant effect on the wear rate of the as-extruded alloys, and the wear rate decreases first and then increases with the increase in the Gd/Nd ratio for the as-aged alloys. The T5 alloy with a Gd/Nd ratio of 1/3 has the best wear resistance. The wear mechanisms of alloys mainly include abrasive wear, oxidation wear, and delamination wear. [ABSTRACT FROM AUTHOR]

The La 0.8- x Pr x Mg 0.2 Ni 3.8 (x = 0, 0.05, 0.1, 0.2, 0.3) alloy were synthesized useing the induction melting method. X-ray diffraction, scanning electron microscope, electron probe micro analyzer, and electrochemical tests were used to analyze the structure and electrochemical performance of the La 0.8- x Pr x Mg 0.2 Ni 3.8 (x = 0–0.3) alloy. It was studied how the Pr element affected the electrochemical characteristics and microstructure of the A 5 B 19 La-Mg-Ni based hydrogen storage alloy. The results show that the alloy consists of the CaCu 5 -LaNi 5 phase, 2 H-Pr 5 Co 19 phase, and 3R-Ce 5 Co 19 phase. The abundance of the A 5 B 19 phase increase with the increase of Pr content, while the abundance of the LaNi 5 phase decrease, and the addition of Pr promotes the formation of the 2 H-Pr 5 Co 19 phase. According to the results of the electrochemical test, every sample has good activation qualities, and the activation can be completed in 3–4 times. The activation properties are not significantly altered by the addition of Pr. The maximum discharge capacity increases at first, then decreases, reaching the highest 371.15 mAh g−1 at x = 0.2. The cyclic stability gradually improves with increasing content of Pr, and the maximum capacity retention rate reaches 85.80 % after 100 cycles. The primary factor influencing the alloy's high rate discharge ability is the exchange current density. With the increase of the exchange current density, the high rate discharge performance is gradually enhanced. • The La-Mg-Ni based hydrogen storage alloy A 5 B 19 has better performance than AB 3 and A 2 B 7. • The hydrogen storage alloy was partially substituted by Pr element with higher electronegativity. • The addition of Pr significantly improves the phase structure stability and cycle stability of the alloy. • The corrosion and oxidation of the alloy electrode during the cycle are improved. [ABSTRACT FROM AUTHOR]

Utilizing element substitution to enhance the hydrogen storage capabilities of Mg-based alloys represents a promising approach in the quest for efficient energy storage solutions. Thereby, in this paper, Ni is chosen to substitute a portion of Mg in a Ce–Mg-based alloy aimed at improving its hydriding and dehydriding performance. Mg 77+ x Ni 20- x Ce 3 (x = 0, 5, 10, 15) alloys are successfully prepared by the vacuum induction melting method. The structural characterizations of the alloys are performed using X-ray diffraction and scanning electron microscope. The alloys are composed of a primary phase of Mg 2 Ni, lamella eutectic composites of Mg + Mg 2 Ni, and some amount of CeMg 12 and Ce 2 Mg 17. In the as-cast Mg 87 Ni 10 Ce 3 alloy, the Mg 2 Ni phase disappears, transforming into a typical eutectic structure of hundreds of nanometers thick Mg–Mg 2 Ni lamellas. This structure significantly enhances the hydrogen storage kinetics, with a hydrogen absorption capacity of 5.66 wt% at 653 K and a desorption capacity of 5.45 wt% over 2 h at 683 K, outperforming other alloys. Moreover, its peak hydrogen release temperature is significantly lower than that of the Mg 92 Ni 5 Ce 3 alloy. The formation of the CeH 2.29 phase within the alloy acts as a catalyst, effectively improving the exothermic and endothermic kinetics of hydrogen absorption and desorption, resulting in a much lower hydrogen desorption activation energy compared to MgH 2. However, the variation in the activation energy of the alloy remains limited, ranging between 66.6 ∼71.1 kJ/mol. [Display omitted] • Mg 77+ x Ni 20- x Ce 3 (x = 0, 5, 10, 15) alloys were prepared in an induction furnace. • Ni substituting for Mg significantly lowers the peak temperature of hydrogen release. • Ni substituting for Mg reduces the desorption activation energy values. • The Mg 87 Ni 10 Ce 3 alloy can absorb more than 5.66 wt % H 2 within 120 min at 653K. [ABSTRACT FROM AUTHOR]

• The study investigates the impact of phytic acid (PA) on the corrosion behavior and charge-discharge processes of Pb-2 %In alloy. • Results demonstrate that PA acts as an efficient inhibitor for Pb-2 %In alloy anode in a 4.0 M H 2 SO 4 solution. • The highest inhibition efficiency (≈ 97.3 %) was achieved with 1 × 10−3 M of PA inhibitor in 4.0 M H 2 SO 4 at 35 °C. • SEM studies confirmed the presence of an adsorbed film from PA on the exterior side of the Pb-2 %In alloy electrode. • These findings highlight the potential of utilizing phytic acid as an effective additive for Pb-2 %In alloy anodes in lead-acid battery applications. This study investigates the impact of phytic acid on the corrosion behavior and charge-discharge processes of Pb-2 %In alloy, which is commonly used as an anode material in lead-acid batteries. Potentiodynamic polarization, electrochemical impedance spectroscopy measurements, as well charge-discharge technique were utilized to conduct investigation both in the absence as well exist of phytic acid (PA) as an inhibitor. In addition, utilizing X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques were carried out for further investigations. Results obtained indicated that PA is an efficient inhibitor for Pb-2 % In as anode in 4 M H 2 SO 4 solution. The inhibitory effectiveness (η %) for Pb-2 % In alloy rises with a rising dose of PA and also rises with rising temperature. The lead acid battery's anode was well enhanced due to the highest inhibition efficiency (≈ 97.3 %), which has been attained in the existence of 1 × 10−3 M of PA inhibitor in 4 M H 2 SO 4 at a temperature of 35 °C. The presence of an adsorbed film from PA was confirmed by SEM studies of the electrode exterior side. One might conclude that an increase in inhibitory effect η % with temperature is an indication that inhibitor molecules are being chemically deposited on the exterior side of Pb-2 %In alloy. DFT data confirms the suggested action of PA towards the inhibition effect and enhancement of the charge-discharge performance of the studied alloy. These findings shed light on the potential of utilizing phytic acid as an effective additive for Pb-2 %In alloy anodes in lead-acid battery applications. [Display omitted] [ABSTRACT FROM AUTHOR]

This study was conducted with a high level of thoroughness. X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM) were used to analyze the phase composition and microstructure of the AM-2024Al and the RO-2024Al. The hardness and porosity of the AM-2024Al, as well as the bonding strength between AM-2024Al and RO-2024Al, were also investigated. Furthermore, the corrosion and tribocorrosion properties and failure mechanisms of the AM-2024Al and the RO-2024Al were systematically and thoroughly compared and analyzed. The results of this comprehensive study revealed that the AM-2024Al displayed a similar phase structure and higher hardness in comparison to the RO-2024Al, and the AM-2024Al was compact and tightly bound to the RO-2024Al with a bonding strength of over 55.5 MPa. Furthermore, the AM-2024Al exhibited better corrosion resistance under PDP (potentiodynamic polarization) corrosion and similar wet sliding wear resistance under an approximate pure friction process (OCP corrosion, namely open circuit potential corrosion) and tribocorrosion compared with the RO-2024Al. These findings provide a high level of confidence in the potential of cold spraying additive manufacture 2024Al as a reliable way to repair damaged RO-2024Al. [Display omitted] • The tribocorrosion is first reported for the CS additive manufacturing 2024Al alloy. • The AM-2024Al exhibits superior anti-corrosion compared to the RO-2024Al. • The AM-2024Al has a comparable tribocorrosion resistance to the RO-2024Al. • Splats (AM-2024Al) and grains (RO-2024Al) are partly peeled during the tribocorrosion. • A plastic deformation layer was generated in the wear track surfaces of the two 2024Al. [ABSTRACT FROM AUTHOR]

The microstructure, phase composition, precipitates evaluation, casting, and mechanical properties of the novel cast Al-4Cu-2.1Er-1Mg-0.2Zr-0.2Cr-0.15Fe-0.15Si-0.1Ti alloy were analyzed using by optical microscope, scanning and transmission electron microscopes, differential scanning calorimetry, thermodynamic calculations, hot cracking and mechanical properties measurements. The positive effect of Cr as a substitution of Mn on plasticity and precipitation strengthening was demonstrated. The 0.2Zr, 0.2Cr and 0.1 Ti as a grain refiners provide a fine grain size of 25 μm in the as-cast state due to primary Al 75–80 Cu 10–12 Er 3–4 Cr 7 phase particles formation as a nucleation centers of Al. The hot cracking index (HCI) of the AlCuErMgCr alloy was 12–14 mm which is similar with HCI of the cast Al-Si-Cu-Mg alloys. The good casting properties in the AlCuErMgCr alloy achieved due to a fine grain structure and narrow solidification range. The contribution of the Al 3 (Zr,Er) (40 nm), Al 45 Cr 7 (6 nm), and S'(θ') (100/5 nm) precipitates is 38.5 MPa, 140.4 MPa, and 198.9 MPa and the calculated contribution from dislocation and precipitates is 262.3 MPa. The ultimate tensile strength (UTS) and elongation (El.) of the AlCuErMgCr alloy are 372 MPa and 6% which is higher in 16.6% and 150%, respectively, than in the Mn-containing alloy. Novel alloy has an excellent combination of yield strength (YS) and plasticity at 20–250°C. The YS and El. are 301 MPa and 6% and 225–250 MPa and 4.6–11.5% at 20 and 200–250°C, respectively. The rupture strength at 250°C after 100 h (σ 100 250) is 106 MPa. Mechanical and casting properties of the novel alloy are superior to the properties of commercial 201.0 (Al-Cu-Mn-Mg-Ag-Ti) alloy. • Cr, replacing Mn, had a positive impact on both plasticity and precipitation strengthening. • 0.2Zr, 0.2Cr, and 0.1Ti as grain refiners resulted in the formation of primary Al 75–80 Cu 10–12 Er 3–4 Cr 7 phase particles. • The AlCuErMgCr alloy displayed an ultimate tensile strength (UTS) of 372 MPa and an elongation (El.) of 6%. • The rupture strength at 250°C after 100 hours was determined to be 106 MPa. [ABSTRACT FROM AUTHOR]

The microstructure and properties of the aged Cu-Cr-Zr-Nb alloy were studied by means of hardness tester, universal tensile testing machine, conductivity meter, X-ray diffraction, scanning electron microscope, and transmission electron microscope. The results indicated that the hardness and TS (tensile strength) of the Cu-Cr-Zr-Nb alloy increased first and subsequently decreased with increasing the aging temperature. Nevertheless, the electrical conductivity is gradually increasing. The aged Cu-Cr-Zr-Nb alloy was mostly made up of Cu matrix, Cr particles, Cr 2 Nb, and CuZr compounds. Due to the effects of dislocations accumulated by cold drawing and twins produced during the aging process, the softening temperature of the alloy reached 590 ℃. When the Cu-Cr-Zr-Nb alloy was aged at 490 ℃, < 111 > replaced < 110 > in the optimal orientation of the alloy, and the KAM (kernel average misorientation) value inside the alloy was the largest. The alloy exhibited great comprehensive properties at 490 ℃ for 1 h, with a hardness of 144.4 HBW, a TS of 521 MPa, and an electrical conductivity of 78.3%IACS. The contribution value of YS (yield strength) at different aging temperatures was further calculated. The computational results showed that precipitation strengthening was the main strengthening mechanism of the Cu-Cr-Zr-Nb alloy, and fine-grained strengthening and dislocation strengthening simultaneously played a supplementary role. • Due to the effects of dislocations accumulated by cold drawing, precipitation strengthening of Cr and twins produced during the aging process, the softening temperature of the Cu-Cr-Zr-Nb alloy reaches 590 ℃. • The Cu-Cr-Zr-Nb alloy exhibits great comprehensive properties at 490 ℃ for 1 h, with a hardness of 144.4 HBW, a tensile strength of 521 MPa, and an electrical conductivity of 78.3 %IACS. • The computational results show that precipitation strengthening is the main strengthening mechanism of the Cu-Cr-Zr-Nb alloy. [ABSTRACT FROM AUTHOR]

• Experimental investigation of wetting behaviour in Cu-In alloy is carried out. • Studies based on scanning electron microscopy and energy dispersive spectroscopy are carried out to identify wetting behaviour. • Indium seems to considerably affect the wetting transition at triple grain junction. This work investigates Cu-In alloy at 15% indium for wetting behaviour after heat treatment at 800 ⁰C. The system is observed to show wetting behaviour at triple junction (grain junction) through Scanning electron microscope imaging. It is observed in energy dispersive spectroscopy that after annealing, increased segregation of indium near triple junction is responsible for this wetting behaviour. The current work is critical to development of advanced materials with better mechanical characteristics at high temperatures. [ABSTRACT FROM AUTHOR]

Zn alloy has attracted much attention as a biodegradable material for biomedical applications. However, due to the significant strain softening of Zn alloys, how to break the bottleneck of synergistic yield strength and uniform elongation is an urgent problem to be solved. In this work, a Zn-2.3Cu-0.8Mn (wt.%) alloy was fabricated via low-temperature extrusion and annealing at 330 °C for 1 h to attain dual heterostructures with bimodal grains and multi-scale second phases, focusing on the effect of heterostructure on the mechanical properties. Uniaxial tensile test and loading-unloading-reloading test were applied to reveal the mechanical properties of the Zn-2.3Cu-0.8Mn alloy, while scanning electron microscope, electron backscatter diffraction, and transmission electron microscope were used to characterize its microstructure. Compared with the as-extruded alloy with uniform and fine grains, 330–1 alloy achieves a better combination of strength and uniform elongation (yield strength: 287.8 ± 8.5 MPa, ultimate tensile strength: 321.4 ± 6.8 MPa, and uniform elongation: 14.2 ± 1.8%). The high strength was primarily attributed to the coordination of grain boundary strengthening, hetero-deformation induced strengthening, Orowan strengthening, and dislocation strengthening. Besides, the coarse grains, twinning, as well as the suppression of grain boundary sliding and phase boundary sliding promoted dislocation proliferation and storage capacity, thereby improving work hardening capacity. The large strain hardening capacity was responsible for excellent plasticity. This study provides a feasible strategy for the design of Zn-based alloys with an excellent combination of high strength and strain hardening capacity. [ABSTRACT FROM AUTHOR]

• Bi 2 Te 3 doped with Se, Sb and Na with various amounts were synthesized by simple melting. • Transport properties have been studied over the temperature range 283–473 K. • Se-doped Bi 2 Te 3 showed interestingly high ZT values at high temperatures. • The maximum ZT was recorded at 1.97 for the highest Sb-doped Bi 1.94 Sb 0.06 Te 3 at 430 K. Bulk alloys of Bi 2 Te 3 doped with various amounts of Se, Sb and Na were synthesized by simple melting. Structural and morphological properties have been checked using x-ray diffraction (XRD) and scanning electron microscope (SEM) observations. XRD and SEM investigations revealed that the obtained samples are of high crystallinity with the structural characteristics of the Bi 2 Te 3 phase. Electrical and thermoelectric properties of the prepared samples were investigated over the temperature range 283–473 K. Seebeck coefficient and electrical and thermal conductivities were measured and studied as functions of temperature between 283 K and 473 K. The power factor (PF) was calculated and examined against the temperature increasing, as well. The thermoelectric figure of merit (ZT) was estimated from the materials power factor and thermal conductivity. The Sb-doped alloy exhibited the largest power factor, recorded at 285.23 µW/m.K2 at 430 K. On the other side, the Sb-doped and the Na-doped Bi 2 Te 3 showed increased ZT than that of the pristine alloy. The maximum ZT was recorded at 1.97 for the highest Sb-doped Bi 1.94 Sb 0.06 Te 3 sample, observed at 430 K. It is believed that the increased number of grain boundaries besides the decreased grain size are main reasons behind the high observed ZT in this work, especially because the phonon scattering on grain boundaries results in reducing the lattice part of the thermal conductivity. [ABSTRACT FROM AUTHOR]

To obtain a robust diffusion-bonded joint at a relatively low temperature, Nb foil was applied as an interlayer to the diffusion bonding of Zr-4 alloy, and a wide process parameter involving the bonding temperature of 720–820 °C and holding time of 30–120 min was investigated to reveal the evolution of interfacial structure and mechanical properties of the joints. The β-(Zr, Nb) and Widmanstädter microstructure formed at the interface induced by the eutectoid transformation of the diffused Zr and Nb at the bonding temperatures over 740 °C. The phase structure and the thickness of β-(Zr, Nb) layer were not considerably influenced by the increase in diffusion parameters while the Widmanstädter zone thickened significantly. Moreover, the tensile strength and elongation of the resultant joints could be stabilized above 433 MPa and 7.8%, respectively, when the bonding temperature exceeded 760 °C with a holding time of 30 min. By extending the holding time to 60 min at 760 °C, the tensile strength and elongation could reach 454 MPa and 12.6%, respectively, comparable to those obtained at an elevated temperature of 820 °C for 30 min. Additionally, the samples fractured at the diffusion layer were characterized by the in-situ tensile test under the scanning electron microscope, and it was discovered that the crack initiation and propagation process occurred mainly between the β-(Zr, Nb) and Widmanstädter diffusion zone. • The well-bonded Zr-4 joints were achieved by the application of Nb interlayer. • The diffusion layer consisted of β-(Zr, Nb) and Widmanstädter microstructure. • The Nb addition lowered bonding temperature without weakening tensile properties. • The fracture occurred between the β-(Zr, Nb) and Widmanstädter diffusion zone. [ABSTRACT FROM AUTHOR]

To improve the bonding strength of the 6061 Al alloy with the plating layer and enhance the corrosion resistance, a Cu/Co-Mo corrosion-resistant plating layer was deposited on its surface. Through Scanning Electron Microscope, it is found that Cu/Co-Mo and the substrate can form an obvious three-layer composite structure, and X-ray diffraction detects that the Co Mo coating is an alloy with obvious amorphous characteristics, and its phase composition is Co 3 Mo. After performance testing, the composite coating improved the corrosion resistance and hardness of the substrate and could play a good role in protecting the 6061 Al alloy. In addition, the mechanism of induced codeposition of Co Mo alloy was investigated, and the deposition of Mo6+ was determined by cyclic voltammetry to be a three-step six-electron irreversible reduction reaction. Chronopotentiometry revealed that Mo6+ underwent a diffusion-controlled transient nucleation process. The AC impedance indicated that the selection of a suitable voltage is beneficial to reduce the hydrogen precipitation reactions during electrodeposition. [ABSTRACT FROM AUTHOR]