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The development of magnesium alloys with superior plasticity and favorable strength is still challenging in aerospace industry. Herein, hot extruded Mg-xNd-2.0Sm-0.4Zn-0.4Zr alloys (x = 0, 0.5, 1.0, 1.5, 2.0 and 2.5 wt.%) were rationally designed and easily prepared in order to implement the favorable combination of strength and plasticity. The effects of Nd element addition on the microstructure and mechanical properties of the hot extruded alloys were systematically investigated by optical microscopy (OM), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The OM results indicated that the grain size of the hot extruded alloys decreased from 27.1 to 14.1 μm with increasing Nd addition from 0 to 2.5 wt.%. Some coarse β phases existed at the grain boundary when the addition of Nd element increased to 2.0 wt.%. The TEM results showed that the nanoscaled basal lamellar precipitates, granular precipitates and prismatic lamellar precipitates formed in α-Mg matrix. And the amount of precipitated phase increased obviously with the increase of Nd element addition. The ultimate tensile strength increased significantly from 203 ± 3.0 to 237 ± 2.5 MPa, and the elongation decreased from 30.5 to 21.2 % when the Nd elements increased from 0 to 2.5 wt.%. The fractographs of the hot extruded alloys could be classified as ductile fracture. [ABSTRACT FROM AUTHOR]

Main aim of this study is to examine change of microstructural and the mechanical properties of Al-7075 alloy depending on B content added with different proportions. Rapid solidification process used to produce the alloys was carried out with a single roll melt spinner via a wheel with a rotational speed of 25 m/s. For the microstructural characterization of the alloys, a scanning electron microscope and X-ray diffraction analyzes were used. According to obtained results, it can be said that B addition led to modification of dimensions and shapes of both α−Al and intermetallic phases occurred, it reduced average grain size from 0.45 μm to 0.34 μm in the microstructure. The B addition also led to dramatically increase in microhardness of the Al-7075 alloy. The microhardness of the alloy with 0.4 wt. % B is 0.19 GPa, this is clearly one times higher than that of the alloy without B addition. The microhardness of the alloy with 1 wt. % B is 0.21 GPa, this is also slightly higher than that of the alloy with 0.4 wt. % B. [ABSTRACT FROM AUTHOR]

With the development and wide application of nickel-based single-crystal superalloys, the effect of Ru on the microstructure stability and high-temperature properties of superalloys is becoming increasingly important. In this study, the effect of Ru on the evolution of the γ′ phase in Ni-Al-Ru ternary alloys during aging treatment was analyzed, using a scanning electron microscope and transmission electron microscope, combined with energy-dispersive spectroscopy. The relationship between chemical partition behavior and γ/γ′ lattice misfit was investigated in detail. During the aging process, Ru addition suppressed the growth rate and rafting process of γ′ precipitates, while the effect of Ru on hindering γ′ phase growth was reduced when the Ru content was over 3 at%. Ru preferentially partitioned to the γ phase, and its partitioning ratio to the γ phase increased with a variation in Ru content from 1 at% to 3 at% and decreased for the NiAl6Ru alloy. Additionally, the lattice misfit of all alloys was positive and reduced with the increase in Ru content, which hindered the Ru atoms to diffuse into the γ phase and promoted the shape of γ′ precipitates to change from cubic to spherical. [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]

The corrosion behavior and microstructure of Mg-3Zn-1Mn-xSr (x = 0, 0.5, 1.0, 1.5, 2.0 wt.%) alloys are investigated by optical microscope (OM), scanning electron microscope (SEM), electrochemical tests and immersion experiments equipped with a dynamic corrosion device. The introduction of Sr element changes the distribution of Mg7Zn3 phase in the Mg-3Zn-1Mn alloy, promoting its precipitation at the grain boundary. Decrease in grain size and second phase spacing can be observed with the increase of Sr content, and the size of semi-continuous second phases (Mg7Zn3 + Mg17Sr2) distributed along grain boundary increases. The corrosion resistance of Mg-3Zn-1Mn-xSr alloys increases with the suitable addition of Sr, but decreases with the addition of excessive Sr, indicating that the critical value exists for the addition of Sr to obtain the optimal corrosion resistance. Optimal corrosion performance (CR = 1.213 ± 0.02mm/y, Icorr = 2.80μA/cm2) of Mg-3Zn-1Mn-1Sr alloy is concluded by immersion tests and electrochemical measurements, and its corrosion morphology manifests uniform corrosion pits and dense structure due to mass accumulation of corrosion products on the damaged surface of Mg matrix. The synergistic effect of the grain size and second phase is used to explain the influence of the variation of Sr content on the corrosion performance of Mg-3Zn-1Mn-xSr alloys. [ABSTRACT FROM AUTHOR]

Hydroxyapatite-carbon nanotubes (HA-CNTs) nanocomposite coating was applied by electrophoretic method on anodized Ti alloy to investigate its stability in simulated body fluid (SBF). The biocoating was characterized by using scanning electron microscope (SEM) for microstructure, X-ray diffraction (XRD) for crystallography. The effect of CNTs concentration on the coating properties was also investigated and found out that CNTs up to 5% has various improving effect on the system. It increased corrosion resistance and adhesion of the coating to the substrate and decreased the number of cracks on the coating. The results of the in vitro test showed that the cell viability increased with increasing the concentration of CNTs to 3 wt.% CNTs. [ABSTRACT FROM AUTHOR]

In this paper, based on the as-cast CuSn10P1 alloy. Semi-solid CuSn10P1 alloy billet was prepared by cold-rolled isothermal treatment strain-induced melting activation (CRITSIMA). The effects of cold-rolling reduction, isothermal temperature, and isothermal time on the microstructure of semi-solid copper alloy billet were studied by metallographic microscope and Image-Pro Plus software. The changes of primary elements in as-cast and semi-solid microstructure were analyzed briefly by a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The results show that with the increase of cold rolling reduction, the average grain diameter of semi-solid microstructure decreases gradually, the average grain roundness increases first and then decreases, and the liquid fraction of the microstructure remains unchanged. During semi-solid isothermal treatment, with the increase of isothermal temperature and the extension of isothermal time, the average grain diameter increases gradually, the average grain roundness increases first and then decreases, and the liquid fraction increases gradually. When cold rolling reduction is 30%, isothermal temperature is 900 ℃, and isothermal time is 20 min, a better microstructure can be obtained. The average grain diameter, average grain roundness, and liquid fraction of semi-solid alloy billet are 66.45 μm, 0.71, and 12.78%, respectively. Sn and P diffuse from the intergranular liquid to the grain inside during the isothermal treatment from as-cast to semi-solid. [ABSTRACT FROM AUTHOR]

The effects of different Ce content on the microstructure and corrosion resistance of Al-5Mg-3Zn-1Cu alloy in metal mold gravity casting were studied in this paper. The microstructure of the alloy was characterized by scanning electron microscope (SEM) and X-Ray diffractometer (XRD). The corrosivity of all alloys in 3.5 wt.%NaCl solution was studied by electrochemical and immersion corrosion techniques. The results show that the microstructure of the alloy is mainly composed of α-Al, T phase, and Al2Cu phase. Ce can refine the organization of the alloy, but when the addition of Ce is higher than 0.25 wt.%, a massive Ce-rich phase appears in the alloy. The results of a potential polarization test show that the corrosion potential of the alloy increases obviously from −1.253 V to −1.193 V with the increase in Ce content in the alloy. [ABSTRACT FROM AUTHOR]

In this work, static mass analysis method and electrochemical test experiment were used to study the corrosion resistance of Mg-12Gd-3Y-1Sm-0.8Al alloy in different heat treatment states. Optical microscope, scanning electron microscope and x-ray diffractometer were used to analyze microstructure. The result shows: The microstructure of different samples are composed of α-Mg, Mg5Gd, Mg24Y5, Mg41Sm5 and Al2RE phases. Heat treatment can change the morphology and distribution of the precipitates, and the precipitates can affect the corrosion behavior as a cathode, thereby improving the corrosion resistance of the alloy in 3.5% NaCl solution. The relative corrosion rates of the different samples can be ranked as T6>T6-18h>T4>As-cast. After aging treatment, the fine and continuous precipitates act as a barrier to prevent the propagation of corrosion. At this time, the alloy has the strongest corrosion resistance. [ABSTRACT FROM AUTHOR]

In this study, a new alloy material Mg-Zn-Zr (ZK60) was designed for the connecting rod. It was found that the blanks sampled along the vertical direction of an extruded bar crack during the roll forging process. The microstructure and precipitates of the extruded bar were observed and analyzed using optical microscope (OM), scanning electron microscope (SEM) and x-ray diffraction (XRD). The result showed that the Zn, Zr, and MnZn2 precipitates were elongated along the extrusion direction. The mechanical anisotropy was investigated by testing the mechanical properties of the specimens sampling from different angles. Hot deformation behavior was further studied using the Gleeble 3500 thermal-mechanical simulator. The tensile and yield strengths were the highest along the extrusion direction, reaching 347 MPa and 301 MPa, respectively. The deformation resistance was also higher in the extrusion direction than that in the vertical direction. Fracture mechanisms of the sample from different directions were discussed. The ZK60 alloy was more susceptible to failure if the deformation direction was parallel to the bands of segregation area and precipitates. [ABSTRACT FROM AUTHOR]

By means of an electrochemical workstation, hydrogen evolution device, optical microscope (OM) and scanning electron microscope (SEM), the corrosion behaviors of an as-rolled Mg-8%Li alloy with a dual phase structure in 0.9 wt.% NaCl and 3.5 wt.% NaCl solutions have been investigated and compared. The results show that when the immersion time exceeds 8 h, the hydrogen evolution rate of the alloy in the 0.9 wt.% NaCl is 3 times higher than that in the 3.5 wt.% NaCl solution. Moreover, the corrosion behaviors of the alloy are obviously different in the two differently concentrated NaCl solutions. In the 3.5 wt.% NaCl solution, the localized corrosion is much more severe and can occur simultaneously in the interior of both the α-Mg and β-Li matrix phases. However, the localized corrosion in the 0.9 wt.% NaCl solution is obviously weak and mainly occurs at the α-Mg phase. [ABSTRACT FROM AUTHOR]

A novel biomaterial Ti-17Mo (mass%) was designed for orthopedic implant applications. Hot working behavior and deformation characteristics were studied in the β-single structure by hot compression tests in the strain rate range 0.01–10 s−1 and temperature range 1123–1273 K using a Thermec Master-Z simulator. The microstructural evolutions of the deformed alloy were studied by a scanning electron microscope equipped with an electron backscattered diffraction detector. The microstructures of the hot deformed alloy showed that dynamic recovery was more active than dynamic recrystallization (DRX). However, partial discontinuous DRX by grain boundary bulging is activated at high temperatures and low strain rates, e.g., 1273 K and 0.01 s−1. Due to the high stacking fault energy of the β phase with a bcc structure, the Ti-17Mo alloy possessed comparatively low activation energy of hot deformation (283 kJ/mol) compared with the conventional Ti alloys bearing multiple alloying elements. [ABSTRACT FROM AUTHOR]

Copyright of Science of Sintering is the property of National Library of Serbia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, Mg-xAl-3Zn alloys (x=0.5-1-2-3 wt.%) were produced by the permanent mold casting method. Microstructural characterization of alloys was done with the help of optical microscope (OM) and scanning electron microscope with energy-dispersive spectroscopy (SEM/EDS). Dry and bio-corrosive wear behaviors of alloys were investigated comparatively. Depending on the amount of Al in the alloys, the intermetallic phases were differentiated. Mg17Al12 phase was only observed in Mg-3Al-3Zn alloy distributed along the grain boundary as a continuous or semicontinuous network. The Mg-3Al-3Zn alloy hardness value was about 61.60±4.23 HV and approximately 30% higher than the other alloys. Dry wear and bio-corrosive (in simulated body fluid (SBF)) wear performances of the alloys were also compared. The abrasive wear mechanism was evident in dry ambient wear due to the intermetallic phases in the structure. Still, the liquid's lubrication effect is much more dominant in the bio-corrosive wear tests carried out in SBF. While Mg-3Al-3Zn wear rate was the lowest in dry wear, it was determined to be the highest in bio-corrosive wear for all applied load conditions. It had been understood that a large amount of Mg17Al12 phase in the structure caused such a result. [ABSTRACT FROM AUTHOR]

A new generation of Ti-xNb-3Fe-9Zr (x = 15 , 20, 25, 30, 35 wt %) alloys have been designed using various theoretical approaches including DV-xα cluster, molybdenum equivalency, and electron to atom ratio. Afterward, designed alloys are fabricated using cold crucible levitation melting technique. The microstructure and mechanical performances of newly designed alloys are characterized in this work using scanning electron microscope and universal testing machine, respectively. Each alloy demonstrates monolithic β phase except Ti-35Nb-3Fe-9Zr alloy which display dual α ″ + β phases. Typically, niobium acts as an isomorphous beta stabilizer. However, in this work, formation of martensitic α ″ phases occurs at 35 wt % of niobium among the series of newly designed alloys. Furthermore, none of the alloys fail till the maximum load capacity of machine, i.e., 100 KN except Ti-35Nb-3Fe-9Zr alloy. Moreover, the Vickers hardness test is carried out on Ti-xNb-3Fe-9Zr alloys which demonstrate slip bands around the indentation for each alloy. Notably, the deformation bands and cracks around the indentations of each alloy have been observed using optical microscopy; Ti-35Nb-3Fe-9Zr demonstrates some cracks along with slip bands around its indentation. The Ti-25Nb-3Fe-9Zr alloy shows the highest yield strength of 1043 ± 20 MPa , large plasticity of 32 ± 0.5 % , and adequate hardness of 152 ± 3.90 Hv among the investigated alloys. The Ti-25Nb-3Fe-9Zr alloy demonstrates good blend of strength and malleability. Therefore, Ti-25Nb-3Fe-9Zr can be used effectively for the biomedical applications. [ABSTRACT FROM AUTHOR]

The beryllium bronze guide sleeve and the aluminum alloy valve body are assembled to form a beryllium bronze-aluminum alloy stepped hole which requires multiple positioning and tool changes during machining, resulting in lower machining efficiency and accuracy. The geometry error and surface quality of beryllium bronze-aluminum alloy stepped holes after reaming were studied in this research. The geometric error (cylindricity, concentricity and verticality) and diameters of the stepped holes were measured by using a three-coordinate measuring machine. The experimental results show that the PCD forming cutters has high geometric error and diameter stability when reaming beryllium bronze-aluminum alloy stepped holes. Under various cutting parameters, the cylindricity of stepped holes was guaranteed to be within 6μm, and the concentricity of stepped holes was guaranteed to be within 6μm, and verticality of stepped holes was guaranteed to be within 2μm. With the increase of spindle speed and feed per tooth, the diameters of beryllium bronze holes increase while the diameters of aluminum alloy holes decrease and then increase. As the cutting allowance increases, the diameters of the beryllium bronze holes and aluminum alloy holes decrease. The laser confocal microscope and scanning electron microscope were used to detect and analyze the surface quality of beryllium bronze-aluminum alloy stepped holes after reaming. The experimental results show that the surface roughness of the beryllium bronze-aluminum alloy stepped holes reamed by using the PCD forming cutter were less than 0.3μm, and the surface roughness of the beryllium holes were slightly larger than the aluminum holes. The fourth group of experimental parameters (spindle speed 1290r/min, feed per tooth 0.01mm/z, cutting allowance 0.06mm) was selected as the actual processing parameters. There are cavities on the surface of the initial stepped holes before reaming and the cavities basically disappear after reaming, so the surface quality of the beryllium bronze-aluminum alloy stepped holes has been greatly improved. [ABSTRACT FROM AUTHOR]

Streams of multimodal three-dimensional (3D) and four-dimensional (4D) data are revolutionizing our ability to design and predict the behavior of a broad array of advanced materials systems. Over the last 10 years, a new 3D imaging platform consisting of a femtosecond (fs) pulsed laser coupled with a focused ion beam scanning electron microscope (FIB SEM) has been developed by UC Santa Barbara in collaboration with Thermo Fisher Scientific (formerly FEI). The femtosecond-laser-enabled FIB SEM, called the TriBeam, has become one of the only 3D serial sectioning methods available that can gather millimeter-scaled multimodal datasets at sub- μ m voxel resolutions; these length scales are critical for many materials problems. Multimodal chemical, crystallographic, and morphological information can be gathered rapidly on a layer-by-layer basis and reconstructed in 3D. Large (gigabyte to terabyte scale) 3D datasets have been generated for a broad array of materials systems, including metallic alloys, ceramics, biomaterials, polymer- and ceramic-matrix composites, and semiconductors. The research tasks performed have resulted in a completely new design, operating with a dual-wavelength femtosecond-pulsed laser on a plasma focused ion beam (PFIB) platform. [ABSTRACT FROM AUTHOR]

Thermite reduction as one of the most promising methods for preparation of TiAl alloy, the metal-slag separation behavior in the whole process of chemical reaction, including both the alloy components and slags to be removed, is still ambiguous. In this paper, the two-step nucleation mechanism was applied to investigate the metal-slag separation behavior in the thermite reduction process for the preparation of TiAl alloy, which was confirmed by thermodynamic calculation based on density functional theory. Moreover, the component of products acquired from thermite reaction was characterized and analyzed by x-ray diffractometer, scanning electron microscope and transmission electron microscope, respectively. According to the results of the experiment and calculation, the formation and separation mechanism between alloy and slag in the process of preparing TiAl alloy via thermite reduction is visualized, which is universal in the whole metallurgical procedure involving redox and slag-making process. [ABSTRACT FROM AUTHOR]

Copyright of Science of Sintering is the property of National Library of Serbia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the machining characteristics of pulse short arc milling (SEAM) Ti6Al4V alloy were studied. In this regard, the influence of SEAM parameters on the material removal rate (MRR), relative electrode wear ratio (REWR), and surface integrity of Ti6Al4V is studied. A wide variety of processing parameters, including different voltages, frequencies, duty cycles, flushing pressures, electrode rotation speeds, and electrode feed rates, are considered in the investigation. Scanning electron microscope (SEM), energy dispersive spectrograph (EDS), and micro-hardness analysis are applied to analyze results. Moreover, a multichannel data acquisition system is used to measure gap voltage and gap current. Obtained results cover the variation of MRR, REWR, surface roughness (Ra), average resolidified layer thickness, and average heat-affected zone thickness with different processing parameters. Furthermore, the electrode surface morphology and chemical composition of the negative growth of REWR are studied. Based on the obtained results, the microstructure of the resolidified layer and heat-affected zone of the workpiece cross-section is confirmed. This study provides a basis for the high-quality pulse SEAM technology of difficult-to-machine (DTM) materials to enter the semi-finishing field. [ABSTRACT FROM AUTHOR]

Information of solidification processes, liquidus temperatures, and phase relationship of the Mg-Mn-Y system in the Mg-rich corner was systematically studied using differential scanning calorimetry (DSC) measurement, x-ray diffraction (XRD) analysis and scanning electron microscope (SEM) analysis. One single-phase region (Hcp), two two-phase-equilibrium regions (Hcp + Cbcc & Hcp + Mg24Y5), and one three-phase-equilibrium region (Hcp + Cbcc + Mg24Y5) were identified in the Mg-rich corner at 550 °C in this work. No ternary phase was observed within the currently studying composition range. Corresponding calculations using the current available thermodynamic description of the Mg-Mn-Y system for the comparison with experimental results were performed. The experimental and calculation results show certain deviations in the phase transition temperatures and the tie-lines of the equilibrium phase regions. The differences are attributed to the extreme low concertation of alloying elements alloyed in Mg in this work, where few studies were performed in literature and nevertheless included in the previous assessment work. Therefore, the current results could provide an essential basis for the further study and revision of the thermodynamic description of the Mg-Mn-Y system and the design/development of new alloy and process of Mg-Mn-Y based alloys. [ABSTRACT FROM AUTHOR]

The current study explores the effect of Overalloyed filler wire (ERNiCrMo-17) on the weldments of alloy C-276 fabricated through pulsed current tungsten inert gas welding (PCTIG) and tungsten inert gas welding (TIG) technique. The optical microstructure shows that current pulsing technique obtained the refined equiaxed microstructure compared to TIG coarse cellular structure. From Scanning electron microscope (SEM), it is identified that secondary precipitates are absent in the boundary zones of the weld zone. Energy dispersive spectroscopy (EDS) confirmed that microsegregations were absent in between the grain and boundary regions. The results of the tensile test verified that fracture was occurred in the base metal, not in the fusion zone. [ABSTRACT FROM AUTHOR]

Alloys strengthened by nanometer-sized Laves phases have been used as structural components working in corrosive environments at high temperatures owing to the favorable physical and chemical properties of Laves phases. However, due to the small sizes of Laves phases in alloys, their precise characterization cannot be realized efficiently by the existing methods. We previously found that under irradiation of a polished Zircaloy-4 alloy [Zr–1.50Sn–0.25Fe–0.15Cr (wt.%)] with a focused, low-energy (30 keV) electron beam, surface Zr atoms in the α-phase matrix, instead of the ones in nanometer-sized Zr(Fe, Cr)2 Laves phases, were able to undergo significant sputtering into vacuum in a field-emission scanning electron microscope (FE-SEM), resulting in the exposure of the Laves-phase nanoparticles (NPs). Based on this surprising physical phenomenon, here we successfully develop a methodology for performing statistical characterization of Laves-phase NPs in fully recrystallized Zircaloy-4 alloys as well as their partially recrystallized counterparts. By comparing the attributes of the Laves-phase NPs in both partially and fully recrystallized alloys, the conventional, tiny Ostwald ripening of the Laves phases was, for the first time, found to occur during the alloy recrystallization process. These understandings are likely to elucidate the universal mechanisms underlying the nucleation and growth of Laves-phase NPs in solid solutions. [ABSTRACT FROM AUTHOR]

Developments in engineering and medicine have allowed patients' health and quality of life to be supported by implants. Unfortunately, widely used titanium-based alloys with aluminum and vanadium are not ideal materials. The first problem is a mechanical mismatch between human bone and the implant material, and the second issue is the presence of Al or V, which are harmful for the human body and health. This article focuses on the holistic design and production of titanium-based materials with vital elements. The zoned, gradient element can exhibit better mechanical properties and improve the connection between the implant and the bone. The samples in two constructions were built with two different zones. The powders for samples were prepared using the powder metallurgy technique with sieve separation. Phillips X-ray X′Pert diffractometer and PDF4 + database performed the phase composition analysis. The Scanning electron microscope allow the samples observation. Stereological methods assessed porosity and PAR M370 Scanning Electrochemical Workstation. The designed technology based on the powder metallurgy method allows for producing functional, two-zoned graded materials with variable porosity. The phase composition analysis confirmed partially synthesis. Additionally, the observation of the microstructure of the sintered samples revealed the presence of two permanently connected zones. Preliminary mechanical research was conducted to evaluate the potential use of the material as an implant material. The proposal to use two-zone construction of components for implants is dictated by the possibility of personalizing implants for patients, taking into account personal characteristics and needs. [Display omitted] • The functionally graded materials based on vital elements were successfully fabricated using powder metallurgy method. • Highly porous FGM with interconnected porosity was prepared by powder metallurgy. • The porous and microstructure evolution in each gradient layer of FGM is revealed. • The effect of Tin use as Process Control Agent were confirmed and allow to obtain more uniform powders. [ABSTRACT FROM AUTHOR]

In this study, the effect of annealing treatment on microstructure and mechanical properties of the Nb-10Hf-1Ti wt.% produced by Spark Plasma Sintering (SPS) was investigated. Scanning electron microscope (SEM), optical microscopy, X-ray diffraction analysis, hardness, and uniaxial tension test were used to characterize the samples. Annealing treatment was carried out in a vacuum of 10-3 Pa at 1150 °C for 1, 3, 5, and 7 hours and in an argon atmosphere at 1350 °C for 5 hours. Internal oxidation and subsequent hafnium oxide formation causes the hardening of the C103 alloy and drastically increases the hardness and tensile strength. However, HfO2 particles formed at the grain boundary cause brittleness and cleavage fracture of samples. Volume fraction, particle size, and mean inter-particle spacing of oxides significantly change by annealing which affects the mechanical properties. The SPSed sample at 1500 °C is softened by annealing at 1150 C for 5 hours and its hardness and yield strength are reduced from 303 to 230 Hv and 538 to 490 MPa respectively. While annealing at 1350 °C for 5 hours increases hardness and yield strength increases to 343 Hv and 581 MPa respectively. [ABSTRACT FROM AUTHOR]

The quaternary light refractory high-entropy alloys of AlxCrTiMo were fabricated by spark plasma sintering method. Investigation of the oxidation kinetics behavior of the alloys with different Al content at 1000 °C shows varying degrees of weight gain, and the curve of the sample with low Al concentration expresses distinctly different variation tendency. Formation process of oxide layers was analyzed and microstructure and cross sections of distribution of elements were examined by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). TiO2 and Al2O3 phases were observed on the oxide film after exposure to air at 1000 °C for 1 h and 7 h time intervals. These experiments show that the Al-content in the alloy can promote the formation of Al2O3, and the equilibrium of the volatilization rate of the refractory elements as well as the formation rate of the oxidation protective layer determines the weight gain of the AlxCrTiMo. [ABSTRACT FROM AUTHOR]

The main focus of the present study is to compare the effect of different alloying elements on Al–Mg alloy foams. Al–Mg15–X10 (X = Cu, Zn and Si) alloy foams were produced via powder metallurgy route by using Mg as a blowing agent. Macro- and microstructural characterisations of the foams were performed using X-ray tomography, X-ray diffraction and scanning electron microscope. Corrosion studies such as weight loss measurement, hydrogen evolution method and potentiodynamic test were conducted. Mechanical properties were evaluated by subjecting the samples to quasi-static compression and microhardness tests. All the alloy foams showed a comparable structure. The Cu-containing foams exhibited the highest strength, while the Zn-containing foams showed the highest expansion. However, the other properties such as brittleness, elastic modulus and burning nature were found to be better for the Si-containing foams. [ABSTRACT FROM AUTHOR]

The laser nitriding was performed in nitrogen gas at room temperature (20 °C) and low temperature (−190 °C) by a low power fiber laser to modify the wear and abrasion resistance of NiTi alloy. The surface roughness and element composition were analyzed by roughness device and energy-dispersive X-ray spectroscopy respectively. The results of roughness show that laser treatment can change the surface roughness due to the laser remelting. The effect of laser nitriding on the microhardness, friction coefficient, and worn scars of NiTi alloy was also studied, which shows that the microhardness of the NiTi alloy increases after laser nitriding. The optical microscope and scanning electron microscope were used to characterize the surface of NiTi alloy after wear testing to observe the microstructure of worn scars. The results show that the laser nitriding with different parameters can induce a nitride layer with different thicknesses and the higher energy deposition is the key factor for the formation of the nitride layer, which can decrease the friction coefficient and reduce wear loss during the application of NiTi alloy. The improvement of wear resistance can be attributed to the hard nitriding layer. [ABSTRACT FROM AUTHOR]

Continuous research into critical functional property enhancement of materials employed in artificial intelligence systems is imperative to overcome performance limitations. This study investigated the thermal and mechanical properties of stir-cast fabricated Al-Cu alloy modified with addition of iron-millscale (IMS) particles varied from 2-6 wt.%. The alloys microstructure was analysed using both optical and scanning electron microscope coupled with energy dispersive spectroscopy (SEM/EDS). PerkinElmer Thermogravimetry/Derivative thermal analyser was used to assess the alloys thermal characteristics while the mechanical properties were evaluated using relevant state of the art equipment. Results show that the best thermal and mechanical properties comparable to established standards were achieved at 6 wt.% IMS particle addition. Contributions to the alloy enhanced performances stemmed from the structure refining propensity of IMS particles. Based on the thermal and mechanical properties demonstrated, the alloy is recommended for application in pneumatic offshore valve actuator used in oil and gas flow process lines. [ABSTRACT FROM AUTHOR]

Herein, we report low-cost and rare-earth-free Cu-doped Mg-Al alloys for drill-free plugging applications and present the influence of Al content on degradation behavior. The phase composition and microstructure of fabricated alloys were characterized by using a scanning electron microscope (SEM) and X-ray diffractometer (XRD). Also, degradation properties were investigated using hydrogen evolution tests and the electrochemical measurements. The results reveal that the Al content is directly related to the proportion of secondary phases, such as Mg2Cu, Mg17Al12, and MgAlCu. Moreover, the Mg17Al12 and MgAlCu phases are distributed at α-Mg grain boundaries, whereas the MgAlCu phase is distributed within the Mg matrix. Acceleration of degradation rate is found due to microgalvanic corrosion in Mg-xAl-2Cu (in wt.%, named as ACx2, x = 0, 3, 5, and 9) alloys. In this regard, Mg2Cu, Mg17Al12, and MgAlCu phases act as a microgalvanic cathode against anodic magnesium matrixes. As such, the degradation rate of ACx2 alloys in 3.5% NaCl solution is ranked from AC02, AC32, AC52, to AC92. In this context, the AC02 alloy shows the fastest degradation rate, 46 times higher than the AC92 alloy. This may provide a practical solution to develop good alternatives for drill-free plugging materials. [ABSTRACT FROM AUTHOR]

In this paper, the hot deformation behavior of A357 alloy was investigated by hot compression tests. Isothermal hot compression simulation tests for A357 alloy were carried out at the conditions of deformation temperature of 350-470 °C, strain rate of 0.001-10 s−1 and engineering strain of 50%. Based on the Prasad instability criterion and dynamic material model, the hot processing maps of A357 alloy were constructed. The microstructure of compressed samples at different areas of the hot processing map was characterized by metallographic and scanning electron microscope and transmission electron microscope. The experimental results showed that the unstable processing zone of A357 alloy was mainly distributed in the high strain rate (10 s−1) and low-temperature (350, 380 °C) region. With an increase in the strain, the unstable zone expanded from low temperature to high temperature (470 °C). The ideal deformation conditions were deformation temperatures of 380-410 °C and strain rates of 0.001-0.01 s−1, and deformation temperatures of 440-470 °C and strain rates of 0.01-1 s−1. When the A357 alloy was extruded with the optimal hot processing parameters, the results suggested that hot extrusion could make the microstructure uniform and fine, thereby improving mechanical properties, especially when the elongation was up to 19.5% higher than the as-cast A357 alloy. [ABSTRACT FROM AUTHOR]

In this study, a molybdenum alloy with dispersed high-entropy particles was fabricated using the powder metallurgy method. The high-entropy powder, composed of Nb, Ta, V, W, and Zr elements with a same atomic fraction, was prepared via high-energy ball milling. Using this powder, an ideal core-shell powder, composed of high-entropy powder as core and Mo powder as shell, was synthesized via the milling and reduction processes. These processes enabled the realization of an ideal microstructure with the high-entropy phase uniformly dispersed in the Mo matrix. The sintered body was successfully fabricated via uniaxial compaction followed by pressureless sintering. The sintered body was analyzed by X-ray diffraction and scanning electron microscope, and the high-entropy phase is uniformly dispersed in the Mo matrix. [ABSTRACT FROM AUTHOR]

The wetting behavior of glass coatings on samarium-cobalt alloys with different roughness at elevated temperatures in air was investigated by a sessile drop method. The wetting properties were analyzed through several parameters, including apparent contact angle, height and diameter of a glass cylinder on the samarium-cobalt alloy, determined by using a high temperature microscope. The morphology evolution of the glass coating was observed by using a scanning electron microscope. The results show that the glass cylinder contracts initially, and then swells followed by wetting and spreading on the samarium-cobalt alloy substrate. This process is explained by the role of air and the increase of capillary number. The dependence of apparent contact angle on surface roughness is related to interface reaction. It is concluded that the surface roughness firstly increases the contact angle, but then promotes wetting due to the wetting transition changing from the Cassie−Baxter state to the Wenzel state in the non-reactive wetting range. The surface roughness hinders the spreading of the glass melt due to the interface reaction between glass and samarium-cobalt alloys in the reactive wetting range. [ABSTRACT FROM AUTHOR]

Aluminum (Al) electrodes doped with metals, such as Sn, Ga, and Mg, were prepared by smelting to study the effects of Mg content on the properties of Al electrodes. After testing the corrosion resistance and electrochemical properties (in 4 M NaOH solution) of the Al–0.08Sn–0.08Ga–xMg alloy, the results were compared to virgin Al and an Al–Sn–Ga alloy. The battery performance was studied by constant current discharge. Scanning electron microscope and energy-dispersive X-ray analysis were used to investigate the corrosion form and discharge surface of the alloys. Results showed that the Mg–Sn and Mg–Ga phases act as corrosion centers enabling negative corrosion potential. Electrochemical test results revealed that compared with the pure Al and Al–Sn–Ga alloy, the Al–0.08Sn–0.08Ga–0.5Mg alloy not only showed a more negative potential but also showed enhanced activity. Moreover, it showed high energy density (3169.7 Wh kg−1) and improved anode efficiency (86.9 ± 0.2%) when used as an anode for an aluminum–air battery in NaOH solution. [ABSTRACT FROM AUTHOR]

In this study, friction stir processing (FSP) is utilized to fabricate FeCoNiCrAl high-entropy alloy reinforced Al5083 composites. The role of the reinforcement and processing pass on microstructure, microhardness, and wear properties of the composites are studied. The surface of the composites was analyzed via scanning electron microscope. The number of the processing passes acts an important role in the production of the composites via FSP technology. XRD result shows that FSP technology can be used for producing FeCoNiCrAl high-entropy alloy reinforced 5083 aluminum matrix composites which does not contain any harmful intermetallic. The properties of the composites are evaluated by microhardness and wear test. The results show that the composites possess higher microhardness and wear resistance than the Al5083 base alloy and FSPed samples without the FeCoNiCrAl high-entropy alloy particles. In all the composites, the sample produced by 5 passes reveals the highest microhardness, the best wear resistance, and the lowest friction coefficient. [ABSTRACT FROM AUTHOR]

The Cu-Cr-Nb alloys were prepared by vacuum induction melting with different cooling methods. The effects of niobium contents and different cooling methods on the microstructures and properties of these alloys were investigated. The microstructures were characterized by optical microscope, scanning electron microscope and transmission electron microscope. The electrical conductivity, hardness and the tensile strength of Cu-Cr-Nb alloys were tested as well. The results showed that the as-cast microstructures of Cu-Cr-Nb alloys consist of primary α phase dendritic and eutectic phase. With the addition of element Nb, the microstructures were refined and the secondary dendritic arm spacing obviously decreased. Compared with the furnace cooling, the homogeneous and refined microstructures were obtained by the graphite mold, and the hardness of the alloys is enhanced greatly. After the heat treatment, two reinforcing phases of Cr and Cr2Nb are precipitated from the copper matrix. The comprehensive properties were obtained when the Nb content is 0.4%. The Cu-1.2Cr-0.4Nb alloy performed by direct aging treatment without solution treatment exhibits the higher performance, the hardness and electrical conductivity are 143HB and 84%IACS, respectively. In addition, the tensile strength and the elastic limit of the Cu-1.2Cr-0.4Nb alloy can reach up to 413.0 and 238 MPa. [ABSTRACT FROM AUTHOR]

In the present paper, the microstructure evolution of semi-solid metal slurry was investigated. The material was tested by rheocasting route. In order to better estimate the materials behavior, the investigation was performed on three series of samples. The rheocasting was conducted different stirring speed of 500, 1000 and 1500rpm and 0.3 solid fraction, before casting. The microstructure was analysed using an optical and scanning electron microscope. The results show that the relationship between the equivalent diameter of Si and α - Al particles with stirring speed can be well fitted to quadratic or linear equation. The results from this study can also be used to optimize the process and study mechanism of the rheocasting process. [ABSTRACT FROM AUTHOR]

This study discussed the influence of chemical composition on the conductivity and on some mechanical properties of Mg-doped Cu-Si alloy. The structural changes accompanying variations of the alloy chemical composition was investigated using Carl ZEISS Scanning Electron Microscope (SEM) (EVO/NA10) and Energy Dispersive Spectroscopy (EDS). The study also discussed the implication of structural changes on the electromechanical behavior. The results obtained were analyzed statistically using one-factor response surface method (RSM-Design Expert software) to evaluate the level of significance of magnesium addition on Cu-3Si-Mg ternary alloy properties. The SEM results revealed fine grains in the Mg-doped Cu-3Si alloy. The study recorded improvement of properties: average ductility of 25.1%, UTS of 285 MPa; hardness of 318 BHN and average electrical conductivity of 53.9% IACS. The statistical analysis indicated that magnesium significantly improved all the tested properties haven recorded P -values < 0.05. The result of optimization revealed Cu-3Si-0.837 Mg as the optimal composition. [ABSTRACT FROM AUTHOR]

Wire electrical discharge machining (Wire EDM) is a spark erosion process that modifies the surface characteristics by creating overlapped craters and oxides on the machined surface. This oxide and metamorphic layer can be advantageous for Mg alloy in terms of improved corrosion resistance and osteoblast activities. In the current work, face-centered central composite design has been used to carry out the experiments on Wire EDM to study the influence of process parameters and to generate the correlation between input parameters and performance characteristics of ZM21 Mg alloy. Performance characteristics chosen for Mg alloy machining are cutting speed, surface roughness and corrosion rate. To identify the important input parameters and a numerical model that fits the response characteristics, analysis of variance has been used. Using a scanning electron microscope (SEM), it has been found that Wire EDM resulted in overlapped craters and formation of µ-cracks on the machined surface, influenced by discharge energy developed across the electrodes. SEM and XRF (x-ray fluorescence) analysis confirm the formation of a metamorphic layer on the machined surface which leads to corrosion resistance improvement as compared to polished ZM21 Mg alloy. Under response surface methodology, desirability function was utilized to obtain the optimal solutions for multi-response characteristics which were validated experimentally and the sample machined at optimal setting shows improved surface morphology with an oxide layer having uniform nanoscale structure. Electrochemical impedance spectroscopy analysis (for 7 days) shows an increasing trend of corrosion resistance for machined samples, which supports the application of Wire EDM for Mg alloy implants. [ABSTRACT FROM AUTHOR]

This research examines the effect of wear testing parameters on the wear behavior of AZ91 alloy prepared through rotary-die equal channel angular pressing (RD-ECAP). An AZ91 alloy was processed by RD-ECAP method at 573 K for up to 16 passes to reduce the grain size to ~ 5 µm. The properties of the alloys produced by RD-ECAP were compared with the as-received alloy. In order to measure the wear behavior of RD-ECAP manufactured alloy with the as-received alloy, wear tests were performed using ball-on-disk apparatus with specific loading conditions and varying sliding speeds. Surface analysis was used to show the presence of delamination, wear debris and plowing using scanning electron microscopes (SEM). The findings showed that, due to the grain refinement and homogeneity of the second phase distribution, RD-ECAP processed magnesium alloys possess increased wear resistance compared to the initial condition (unprocessed alloy), which makes them suitable for applications in aerospace, automotive and structural industries. Besides, the weight loss reduced with the increase of RD-ECAP pass numbers. Furthermore, increasing in applied load had a more dramatic effect on wear resistance compared to increasing sliding speed and sliding time. [ABSTRACT FROM AUTHOR]

There has been great attention on high-entropy alloys (HEAs) over the past decade. Unlike conventional alloy systems, HEAs commonly include at least five principal elements with equiatomic or near-equiatomic ratio. HEAs with their superior mechanical, magnetic, and thermal properties are promising materials for critical engineering applications. Medium-entropy alloys (MEAs), which consist of less than five principal elements, have very similar structural features with HEAs such as robust thermodynamic stability and exceptional mechanical performance. The insights of MEAs have not been fully revealed yet. In the present study, novel MEAs (Cu20Ni20Al30Ti30, Cu25Ni25Al25Ti25, Cu34Ni22Al22Ti22, and Cu35Ni25Al20Ti20) have been designed using thermo-physical calculations and Thermo-Calc software. These MEAs were then produced using copper heart arc melting and suction cast into cylindrical rods with 3 mm diameters. X-ray diffraction (XRD), optical microscope (OM), transmission electron microscope (TEM), scanning electron microscope (SEM), and energy-dispersive spectroscopy (EDS) were used for structural characterization. The corresponding results reveal that the Cu20Ni20Al30Ti30, MEA, consists of a body-centered cubic (BCC-B2) phase with intermetallic compounds (ICs), whereas Cu25Ni25Al25Ti25 has single BCC-B2 phase. When the amounts Cu and Ni are increased, system drives itself toward a face-centered cubic (FCC) structure. A dual BCC and FCC composite Cu35Ni25Al20Ti20 has been detected as the most promising MEA among the others with 820 and 1338 MPa measured yield and compressive strength, respectively. [ABSTRACT FROM AUTHOR]

The functional grade composite Cu-11Ni-4Si/10wt.%TiC along with Cu- 11Ni-4Si alloy was stir cast, followed by horizontal-centrifuge cast technique. Cast sample was prepared at a dimension Fout100 x Fin85 x 100 mm. A comparative analysis for non-lubricated slide tribology at inner wall zone (1-5 mm), middle wall zone (5-10 mm) and outer wall zone (10- 14 mm) of composites and alloy, was performed utilizing pin-on-disc tribometer. Observed a proportional raise in wear and friction with rise in applied loads and slid distances. For alloy and composite, a slight decline in wear was seen at medium velocity; showing a gradual deduction in friction with rise in slid velocity, while alloy wear showed a linear growth. Rate of increase in wear response with respect to change in distance was less prominent, compared to its response with load. Worn surfaces analysis of composite using Scanning Electron Microscope showed the presence of Mechanically Mixed Layers, which reduced friction at higher slid velocities resulting in lower wear. The phase formations and presence of oxides were confirmed by X-ray diffraction (XRD) and Energy dispersive spectrometers (EDS) results respectively. [ABSTRACT FROM AUTHOR]

The effect of In on melting property, microstructure and mechanical properties of Sn–40Bi–xIn (x = 0, 1, 2, 4, 6, 8 wt%, respectively) alloys was investigated by means of differential scanning calorimetry, scanning electron microscope, X-ray diffraction and tensile test. The results show that the solidus temperature and the liquidus temperature decrease with the increase in In content. The 1In, 2In and 4In alloys are composed of Sn–Bi eutectic and β–Sn dendrites with In atoms dissolved, whereas 6In and 8In alloys composed of Sn–Bi eutectics, BiIn–Sn metastable phases, Bi particles and primary β–Sn phases. At room temperature, 6In exhibits the maximum ultimate tensile strength of 77 MPa, while 4In displays a more outstanding elongation rate of 42%. Moreover, 2In alloy exhibits an even outstanding elongation behavior (above 300%) at temperatures of 100 and 120 °C. [ABSTRACT FROM AUTHOR]

To study the application of scanning electron microscope in metal materials. The properties of metals and their alloys are determined by chemical composition, crystal structure and microstructure. Scanning electron microscope (SEM) in the research category, from metal fracture study, alloy and related components, powder contact gold, element diffusion and inclusion analysis, contact materials research and so on several aspects, through the relevant data, to concrete analysis of metal materials in the application of scanning electron microscope. The scanning electron microscope (SEM) can correspond the observation of metal structure with the analysis of chemical composition, and is especially helpful for the analysis of metal fracture due to the large focal depth and the three-dimensional sense of electronic image. Scanning electron microscope analysis element range: the spectrometer is B5~Ug2, the spectrometer is Na11~Ug2. The sensitivity of detected elements is about 0.2%~0.01%. Antioxidant coatings of metals and their alloys can be developed. It can determine the diffusion rate, diffusion layer thickness, coating composition and phase composition of the element under different process systems. The diffusion and mechanism of coating, heat diffusion welding, bimetal and explosion composite metal under different process systems can be studied. It is convenient to study the oxidation and corrosion mechanism of metals and alloys and to evaluate the brittleness of materials, determine the fracture of materials in what state, study the change of phase composition and grain boundary composition, determine the degree of segregation of alloy elements, etc. Scanning electron microscope can not only observe the surface morphology of metal material, but also conduct qualitative and quantitative analysis of metal material elements, so that the surface morphology and element analysis correspond to each other, which is conducive to the better use and development of metal materials, and with the development of science and technology, will play a greater role. [ABSTRACT FROM AUTHOR]

Evaluation of inorganic and organic compounds as corrosion inhibitors of Cu-Zn alloys in H2SO4 and HNO3 solutions was studied using potentiodynamic and impedance spectroscopy along with scanning electron microscope (SEM) and energy dispersive X-Ray analyzer (EDX) investigations. The corrosion inhibition of Cu-Zn alloys was investigated in oxy acid solutions using inorganic potassium permanganate and di-hydrogen phosphate, amino acids as environmentally safe materials, commercial cooling water, and green tea extracts. Both potassium permanganate and di-hydrogen phosphate improve the corrosion resistance of Cu-Zn alloys. Phosphate appears more effective as corrosion inhibitor for Cu-Zn alloys than permanganate. The inhibition efficiency (IE%) of the different amino acids such as valine, leucine and lysine was also calculated. The experimental results have shown that amino acid-like lysine can be used as an efficient corrosion inhibitor for the Cu-Zn alloys in oxy acid solutions. This may be due to the presence of two amino groups adsorbed together. For lysine, inhibition efficiency, IE%, of ~87 and ~59 is for H2SO4 and ~96.3 and 54.9 for HNO3 for alloy I and II respectively are observed. Due to the composition of green water have a great effect on the inhibition action on Cu-Zn alloys which reaching 91.8 and 96.5% for Alloy I and 95.4 and 87.1% for Alloy II in 0.5 M H2SO4 and HNO3 respectively. Although benzotriazole, in cooling water, is an excellent inhibitor suitable for use in a wide variety of environments, it has toxic properties. So, much of the recent researches have focused on formulating new and more environmentally acceptable preservation solutions. The green tea, as plant extract, will be very environmentally friendly. The EDX confirm the formation of a protective layer on the Cu-Zn alloys containing aluminum in Alloy II. This sequence reflects the beneficial effects of Al in Alloy II. The presence of 2.43% Al in Alloy II improves the corrosion resistance due to the formation of thin, transparent, stable and self - healing Al2O3 layer. This confirmed the results obtained from the potentiodynamic polarization measurements and EIS methods. [ABSTRACT FROM AUTHOR]

The as-extruded NQZ310K (Mg-3.0Nd-1.0Ag-0.2Zn-0.4Zr, mass fraction) alloy was annealed at 300, 350, 400, 450, and 500 °C, respectively. Microstructures of the alloy were observed by an optical microscope and a scanning electron microscope equipped with an energy-dispersive X-ray spectroscope. Ambient mechanical properties were evaluated by tensile tests and nanoindentation tests, and corrosion behavior in simulated body fluid was measured by immersion test. The results show that both matrix grains and precipitates grow up with increasing annealing temperature, and the amount of the precipitates is reduced. The yield strength of the alloy under the as-extruded condition and annealed at 300 and 350 °C is 297, 313, and 298 MPa, and the ultimate tensile strength of it is 327 , 328 , and 315 MPa, respectively, indicating high yield ratio. After annealing at 400, 450, and 500 °C, the yield strength reduces faster than the ultimate tensile strength, resulting in the yield ratio decrease from 0.95 to 0.61, and the elongation improves significantly from 12.3 to 25.5%. The alloy annealed at 350 °C presents the lowest corrosion rate, and then the corrosion resistance of the alloy decreases with increasing annealing temperature. The effects of annealing on microstructure, mechanical and corrosion properties of the as-extruded NQZ310K alloy were also compared with the properties of solution treated alloy. [ABSTRACT FROM AUTHOR]

In the current research, the effect of Ag on the mechanical properties of Ti5Al2.5Fe alloy was investigated. The Ti5Al2.5Fe alloy, with different amounts of Ag ranged from 1 to 5 wt. % was prepared by mechanical mixing and then fabricated by hot pressing at 950 oC for 15 min under 50 MPa. Three holding steps were applied to the powder compacts to restrain the liquid phases inside graphite die before reaching the maximum sintering temperature. The sintered samples were subjected to hardness, bending and wear tests to study the effect Ag on the mechanical properties of Ti5Al2.5Fe alloy. The microstructural characterization was carried out by means of optical and scanning electron microscope. The results showed that Ag played a differential role on the mechanical properties supported by microstructural constituents. The bending strength and hardness of the produced samples increased with the addition of Ag, the hardness of the alloys then tended to decrease with increasing Ag content but still remained above the hardness of Ti5Al2.5Fe alloy. Wear test also showed similar trends with hardness test results. Finally, the optimum Ag content for the Ti5Al2.5Fe alloy was determined as 1 wt.%. XRD analysis showed that undissolved Ag content was the main reason for the decrease in the mechanical properties. [ABSTRACT FROM AUTHOR]

Cobalt-Nickel (Co-Ni) alloy coatings were prepared by jet electrodeposition on brass substrate under different Co2+/Ni2+ ratio contents (M = 2:1, 1:1, 1:2 and 1:3) and solution flow rates (from 2.0 to 4.5 L/min). The surface morphology, element content, and phase structure of the coating were observed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and X-ray diffractometer (XRD). The hardness and wear resistance of the coatings were also measured. The results showed that the Co content in coatings was greater than 70%, no matter at what flow rate and concentration. With an increase of the flow rate, the Co content in the coating increases, and the grain size on the surface of the coating decreases, which leads to increased hardness of the coating. However, the flow rate of the plating solution has little effect on the grain growth orientation, and the phase structure is dominated by the elemental content of the coating. The coatings are in a single phase of hexagonal close-packed (HCP) when the Co content is more than 80%, while the coatings are in dual phases of the HCP and face-centered cubic (FCC) when the Co content is less than 80%. With an increase in the Co content, the grain size decreases, and consequently, the hardness and wear resistance of the alloy increase. A Co-Ni alloy coating with stable composition can be obtained when the ratio of Co2+ to Ni2+ is 2:1. [ABSTRACT FROM AUTHOR]