Subjects -> METALLURGY (Total: 59 journals)
Showing 1 - 10 of 10 Journals sorted alphabetically
Acta Metallurgica Slovaca     Open Access   (Followers: 2)
Advanced Device Materials     Open Access   (Followers: 6)
American Journal of Fluid Dynamics     Open Access   (Followers: 44)
Archives of Metallurgy and Materials     Open Access   (Followers: 9)
Asian Journal of Materials Science     Open Access   (Followers: 4)
Canadian Metallurgical Quarterly     Hybrid Journal   (Followers: 21)
Complex Metals     Open Access   (Followers: 2)
Energy Materials : Materials Science and Engineering for Energy Systems     Hybrid Journal   (Followers: 24)
Graphene and 2D Materials     Open Access   (Followers: 6)
Handbook of Ferromagnetic Materials     Full-text available via subscription   (Followers: 1)
Handbook of Magnetic Materials     Full-text available via subscription   (Followers: 2)
High Temperature Materials and Processes     Open Access   (Followers: 6)
Indian Journal of Engineering and Materials Sciences (IJEMS)     Open Access   (Followers: 11)
International Journal of Metallurgy and Alloys     Full-text available via subscription   (Followers: 2)
International Journal of Metals     Open Access   (Followers: 7)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 12)
International Journal of Mining and Geo-Engineering     Open Access   (Followers: 4)
Ironmaking & Steelmaking     Hybrid Journal   (Followers: 5)
ISIJ International - Iron and Steel Institute of Japan     Full-text available via subscription   (Followers: 26)
Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Proceedings of Higher Schools. Powder Metallurgy аnd Functional Coatings)     Full-text available via subscription   (Followers: 2)
JOM Journal of the Minerals, Metals and Materials Society     Hybrid Journal   (Followers: 35)
Journal of Advanced Joining Processes     Open Access  
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of Cluster Science     Hybrid Journal  
Journal of Heavy Metal Toxicity and Diseases     Open Access  
Journal of Iron and Steel Research International     Hybrid Journal   (Followers: 11)
Journal of Materials & Metallurgical Engineering     Full-text available via subscription   (Followers: 2)
Journal of Materials Processing Technology     Hybrid Journal   (Followers: 21)
Journal of Metallurgical Engineering     Open Access   (Followers: 4)
Journal of Sustainable Metallurgy     Hybrid Journal   (Followers: 3)
Materials Science and Metallurgy Engineering     Open Access   (Followers: 7)
Metal Finishing     Full-text available via subscription   (Followers: 20)
Metallurgical and Materials Engineering     Open Access   (Followers: 7)
Metallurgical and Materials Transactions A     Hybrid Journal   (Followers: 42)
Metallurgical and Materials Transactions B     Hybrid Journal   (Followers: 32)
Metallurgical and Materials Transactions E     Full-text available via subscription   (Followers: 2)
Metallurgical Research & Technology     Full-text available via subscription  
Metallurgical Research and Technology     Full-text available via subscription   (Followers: 8)
Metallurgy and Foundry Engineering     Open Access   (Followers: 3)
Mining, Metallurgy & Exploration     Hybrid Journal  
Powder Diffraction     Full-text available via subscription   (Followers: 1)
Powder Metallurgy     Hybrid Journal   (Followers: 35)
Powder Metallurgy and Metal Ceramics     Hybrid Journal   (Followers: 7)
Powder Metallurgy Progress     Open Access   (Followers: 5)
Practical Metallography     Full-text available via subscription   (Followers: 6)
Rare Metals     Hybrid Journal   (Followers: 3)
Revista de Metalurgia     Open Access  
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Revista Remetallica     Open Access   (Followers: 1)
Russian Metallurgy (Metally)     Full-text available via subscription   (Followers: 4)
Science and Technology of Welding and Joining     Hybrid Journal   (Followers: 8)
Soldering & Surface Mount Technology     Hybrid Journal   (Followers: 2)
Steel Times lnternational     Partially Free   (Followers: 19)
Transactions of the IMF     Hybrid Journal   (Followers: 14)
Transactions of the Indian Institute of Metals     Hybrid Journal   (Followers: 5)
Tungsten     Hybrid Journal  
Universal Journal of Materials Science     Open Access   (Followers: 3)
Welding in the World     Hybrid Journal   (Followers: 8)
Welding International     Hybrid Journal   (Followers: 11)
Вісник Приазовського Державного Технічного Університету. Серія: Технічні науки     Open Access  
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International Journal of Minerals, Metallurgy, and Materials
Journal Prestige (SJR): 0.559
Citation Impact (citeScore): 1
Number of Followers: 12  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1674-4799 - ISSN (Online) 1869-103X
Published by Springer-Verlag Homepage  [2656 journals]
  • Synthesis, characterization and radioluminescence properties of
           erbium-doped yttria phosphors
    • Abstract: Radioluminescence (RL) behaviour of erbium-doped yttria nanoparticles (Y2O3:Er3+ NPs) which were produced by sol-gel method was reported for future scintillator applications. NPs with dopant rates of 1at%, 5at%, 10at% and 20at% Er were produced and calcined at 800°C, and effect of increased calcination temperature (1100°C) on the RL behaviour was also reported. X-ray diffraction (XRD) results showed that all phosphors had the cubic Y2O3 bixbyite-type structure. The lattice parameters, crystallite sizes (CS), and lattice strain values were calculated by Cohen-Wagner (C-W) and Williamson-Hall (W-H) methods, respectively. Additionally, the optimum solubility value of the Er3+ dopant ion in the Y2O3 host lattice was calculated to be approximately 4at% according to Vegard’s law, which was experimentally obtained from the 5at% Er3+ ion containing solution. Both peak shifts in XRD patterns and X-ray photoelectron spectroscopy (XPS) analyses confirmed that Er3+ dopant ions were successfully incorporated into the Y2O3 host structure. High-resolution transmission electron microscopy (HRTEM) results verified the average CS values and agglomerated NPs morphologies were revealed. Scanning electron microscopy (SEM) results showed the neck formation between the particles due to increased calcination temperature. As a result of the RL measurements under a Cu Kα X-ray radiation (wavelength, λ = 0.154 nm) source with 50 kV and 10 mA beam current, it was determined that the highest RL emission belonged to 5at% Er doped sample. In the RL emission spectrum, the emission peaks were observed in the wavelength ranges of 510–575 nm (2H11/2, 4S3/2-4I15/2; green emission) and 645–690 nm (4F9/2-4I15/2; red emission). The emission peaks at 581, 583, 587, 593, 601, 611 and 632 nm wavelengths were also detected. It was found that both dopant rate and calcination temperature affected the RL emission intensity. The color shifted from red to green with increasing calcination temperature which was attributed to the increased crystallinity and reduced crystal defects.
      PubDate: 2021-05-04
       
  • Editorial for special issue on USTB-RWTH Aachen’s 40 years of
           collaboration
    • PubDate: 2021-05-01
       
  • Determining role of heterogeneous microstructure in lowering yield ratio
           and enhancing impact toughness in high-strength low-alloy steel
    • Abstract: Here we present a novel approach of intercritical heat treatment for microstructure tailoring, in which intercritical annealing is introduced between conventional quenching and tempering. This induced a heterogeneous microstructure consisting of soft intercritical ferrite and hard tempered martensite, resulting in a low yield ratio (YR) and high impact toughness in a high-strength low-alloy steel. The initial yielding and subsequent work hardening behavior of the steel during tensile deformation were modified by the presence of soft intercritical ferrite after intercritical annealing, in comparison to the steel with full martensitic microstructure. The increase in YR was related to the reduction in hardness difference between the soft and hard phases due to the precipitation of nano-carbides and the recovery of dislocations during tempering. The excellent low-temperature toughness was ascribed not only to the decrease in probability of microcrack initiation for the reduction of hardness difference between two phases, but also to the increase in resistance of microcrack propagation caused by the high density of high angle grain boundaries.
      PubDate: 2021-05-01
       
  • In-depth analysis of the fatigue mechanism induced by inclusions for
           high-strength bearing steels
    • Abstract: A numerical study of stress distribution and fatigue behavior in terms of the effect of voids adjacent to inclusions was conducted with finite element modeling simulations under different assumptions. Fatigue mechanisms were also analyzed accordingly. The results showed that the effects of inclusions on fatigue life will distinctly decrease if the mechanical properties are close to those of the steel matrix. For the inclusions, which are tightly bonded with the steel matrix, when the Young’s modulus is larger than that of the steel matrix, the stress will concentrate inside the inclusion; otherwise, the stress will concentrate in the steel matrix. If voids exist on the interface between inclusions and the steel matrix, their effects on the fatigue process differ with their positions relative to the inclusions. The void on one side of an inclusion perpendicular to the fatigue loading direction will aggravate the effect of inclusions on fatigue behavior and lead to a sharp stress concentration. The void on the top of inclusion along the fatigue loading direction will accelerate the debonding between the inclusion and steel matrix.
      PubDate: 2021-05-01
       
  • Effect of microstructure on corrosion behavior of high strength martensite
           steel—A literature review
    • Abstract: The high strength martensite steels are widely used in aerospace, ocean engineering, etc., due to their high strength, good ductility and acceptable corrosion resistance. This paper provides a review for the influence of microstructure on corrosion behavior of high strength martensite steels. Pitting is the most common corrosion type of high strength stainless steels, which always occurs at weak area of passive film such as inclusions, carbide/intermetallic interfaces. Meanwhile, the chromium carbide precipitations in the martensitic lath/prior austenite boundaries always result in intergranular corrosion. The precipitation, dislocation and grain/lath boundary are also used as crack nucleation and hydrogen traps, leading to hydrogen embrittlement and stress corrosion cracking for high strength martensite steels. Yet, the retained/reversed austenite has beneficial effects on the corrosion resistance and could reduce the sensitivity of stress corrosion cracking for high strength martensite steels. Finally, the corrosion mechanisms of additive manufacturing high strength steels and the ideas for designing new high strength martensite steel are explored.
      PubDate: 2021-05-01
       
  • Hydrogen effect on the mechanical behaviour and microstructural features
           of a Fe-Mn-C twinning induced plasticity steel
    • Abstract: The influences of hydrogen on the mechanical properties and the fracture behaviour of Fe-22Mn-0.6C twinning induced plasticity steel have been investigated by slow strain rate tests and fractographic analysis. The steel showed high susceptibility to hydrogen embrittlement, which led to 62.9% and 74.2% reduction in engineering strain with 3.1 and 14.4 ppm diffusive hydrogen, respectively. The fracture surfaces revealed a transition from ductile to brittle dominated fracture modes with the rising hydrogen contents. The underlying deformation and fracture mechanisms were further exploited by examining the hydrogen effects on the dislocation substructure, stacking fault probability, and twinning behaviour in pre-strained slow strain rate test specimens and notched tensile specimens using coupled electron channelling contrast imaging and electron backscatter diffraction techniques. The results reveal that the addition of hydrogen promotes planar dislocation structures, earlier nucleation of stacking faults, and deformation twinning within those grains which have tensile axis orientations close to <111>//rolling direction and <112gt;//rolling direction. The developed twin lamellae result in strain localization and micro-voids at grain boundaries and eventually lead to grain boundary decohesion.
      PubDate: 2021-05-01
       
  • Superior corrosion resistance-dependent laser energy density in (CoCrFeNi)
           95 Nb 5 high entropy alloy coating fabricated by laser cladding
    • Abstract: (CoCrFeNi)95Nb5 high entropy alloy (HEA) coatings were successfully fabricated on a substrate of Q235 steel by laser cladding technology. These (CoCrFeNi)95Nb5 HEA coatings possess excellent properties, particularly corrosion resistance, which is clearly superior to that of some typical bulk HEA and common engineering alloys. In order to obtain appropriate laser cladding preparation process parameters, the effects of laser energy density on the microstructure, microhardness, and corrosion resistance of (CoCrFeNi)95Nb5 HEA coating were closely studied. Results showed that as the laser energy density increases, precipitation of the Laves phase in (CoCrFeNi)95Nb5 HEA coating gradually decreases, and diffusion of the Fe element in the substrate intensifies, affecting the integrity of the (CoCrFeNi)95Nb5 HEA. This decreases the microhardness of (CoCrFeNi)95Nb5 HEA coatings. Moreover, the relative content of Cr2O3, Cr(OH)3, and Nb2O5 in the surface passive film of the coating decreases with increasing energy density, causing corrosion resistance to decrease. This study demonstrates the controllability of a high-performance HEA coating using laser cladding technology, which has significance for the laser cladding preparation of other CoCrFeNi-system HEA coatings.
      PubDate: 2021-05-01
       
  • Effect of Al 2 O 3 on the viscosity of CaO-SiO 2 -Al 2 O 3 -MgO-Cr 2 O 3
           slags
    • Abstract: We investigated the effect of Al2O3 content on the viscosity of CaO-SiO2-Al2O3-8wt%MgO-1wt%Cr2O3 (mass ratio of CaO/SiO2 is 1.0, and Al2O3 content is 17wt%–29wt%) slags. The results show that the viscosity of the slag increases gradually with increases in the Al2O3 content in the range of 17wt% to 29wt% due to the role of Al2O3 as a network former in the polymerization of the aluminosilicate structure of the slag. With increases in the Al2O3 content from 17wt% to 29wt%, the apparent activation energy of the slags also increases from 180.85 to 210.23 kJ/mol, which is consistent with the variation in the critical temperature. The Fourier-transform infrared spectra indicate that the degree of polymerization of this slag is increased by the addition of Al2O3. The application of Iida’s model for predicting the slag viscosity in the presence of Cr2O3 indicates that the calculated viscosity values fit well with the measured values when both the temperature and Al2O3 content are at relatively low levels, i.e., the temperature range of 1673 to 1803 K and the Al2O3 content range of 17wt%–29wt% in CaO-SiO2-Al2O3-8wt%MgO-1wt%Cr2O3 slag.
      PubDate: 2021-05-01
       
  • Effect of weld microstructure on brittle fracture initiation in the
           thermally-aged boiling water reactor pressure vessel head weld metal
    • Abstract: Effects of the weld microstructure and inclusions on brittle fracture initiation are investigated in a thermally aged ferritic high-nickel weld of a reactor pressure vessel head from a decommissioned nuclear power plant. As-welded and reheated regions mainly consist of acicular and polygonal ferrite, respectively. Fractographic examination of Charpy V-notch impact toughness specimens reveals large inclusions (0.5–2.5 µm) at the brittle fracture primary initiation sites. High impact energies were measured for the specimens in which brittle fracture was initiated from a small inclusion or an inclusion away from the V-notch. The density, geometry, and chemical composition of the primary initiation inclusions were investigated. A brittle fracture crack initiates as a microcrack either within the multiphase oxide inclusions or from the de-bonded interfaces between the uncracked inclusions and weld metal matrix. Primary fracture sites can be determined in all the specimens tested in the lower part of the transition curve at and below the 41-J reference impact toughness energy but not above the mentioned value because of the changes in the fracture mechanism and resulting changes in the fracture appearance.
      PubDate: 2021-05-01
       
  • Stress-state dependence of dynamic strain aging: Thermal hardening and
           blue brittleness
    • Abstract: This study aims to discover the stress-state dependence of the dynamic strain aging (DSA) effect on the deformation and fracture behavior of high-strength dual-phase (DP) steel at different deformation temperatures (25–400°C) and reveal the damage mechanisms under these various configurations. To achieve different stress states, predesigned specimens with different geometric features were used. Scanning electron microscopy was applied to analyze the fracture modes (e.g., dimple or shear mode) and underlying damage mechanism of the investigated material. DSA is present in this DP steel, showing the Portevin-Le Chatelier (PLC) effect with serrated flow behavior, thermal hardening, and blue brittleness phenomena. Results show that the stress state contributes distinctly to the DSA effect in terms of the magnitude of thermal hardening and the pattern of blue brittleness. Either low stress triaxiality or Lode angle parameter promotes DSA-induced blue brittleness. Accordingly, the damage mechanisms also show dependence on the stress states in conjunction with the DSA effect.
      PubDate: 2021-05-01
       
  • Multiphase-field simulation of austenite reversion in medium-Mn steels
    • Abstract: Medium-Mn steels have attracted immense attention for automotive applications owing to their outstanding combination of high strength and superior ductility. This steel class is generally characterized by an ultrafine-grained duplex microstructure consisting of ferrite and a large amount of austenite. Such a unique microstructure is processed by intercritical annealing, where austenite reversion occurs in a fine martensitic matrix. In the present study, austenite reversion in a medium-Mn alloy was simulated by the multiphase-field approach using the commercial software MICRESS® coupled with the thermodynamic database TCFE8 and the kinetic database MOBFE2. In particular, a faceted anisotropy model was incorporated to replicate the lamellar morphology of reversed austenite. The simulated microstructural morphology and phase transformation kinetics (indicated by the amount of phase) concurred well with experimental observations by scanning electron microscopy and in situ synchrotron high-energy X-ray diffraction, respectively.
      PubDate: 2021-05-01
       
  • Ultrahigh cycle fatigue fracture mechanism of high-quality bearing steel
           obtained through different deoxidation methods
    • Abstract: The mechanism of oxide inclusions in fatigue crack initiation in the very-high cycle fatigue (VHCF) regime was clarified by subjecting bearing steels deoxidized by Al (Al-deoxidized steel) and Si (Si-deoxidized steel) to ultrasonic tension-compression fatigue tests (stress ratio, R = −1) and analyzing the characteristics of the detected inclusions. Results show that the main types of inclusions in Si- and Al-deoxidized steels are silicate and calcium aluminate, respectively. The content of calcium aluminate inclusions larger than 15 µm in Si-deoxidized steel is lower than that in Al-deoxidized steel, and the difference observed may be attributed to different inclusion generation processes during melting. Despite differences in their cleanliness and total oxygen contents, the Si- and Al-deoxidized steels show similar VHCF lives. The factors causing fatigue failure in these steels reveal distinct differences. Calcium aluminate inclusions are responsible for the cracks in Al-deoxidized steel. By comparison, most fatigue cracks in Si-deoxidized steel are triggered by the inhomogeneity of a steel matrix, which indicates that the damage mechanisms of the steel matrix can be a critical issue for this type of steel. A minor portion of the cracks in Si-deoxidized steel could be attributed to different types of inclusions. The mechanisms of fatigue fracture caused by calcium aluminate and silicate inclusions were further analyzed. Calcium aluminate inclusions first separate from the steel matrix and then trigger crack generation. Silicate inclusions and the steel matrix are closely combined in a fatigue process; thus, these inclusions have mild effects on the fatigue life of bearing steels. Si/Mn deoxidation is an effective method to produce high-quality bearing steel with a long fatigue life and good liquid steel fluidity.
      PubDate: 2021-05-01
       
  • Influence of sample preparation on nanoindentation results of
           twinning-induced plasticity steel
    • Abstract: Nanoindentation is an attractive characterization technique, as it not only measures the local properties of a material but also facilitates understanding of deformation mechanisms at submicron scales. However, because of the complex stress-strain field and the small scale of the deformation under the nanoindenter, the results can be easily influenced by artifacts induced during sample preparation. In this work, a systematic study was conducted to better understand the influence of sample preparation methods on the nanoindentation results of ductile metals. All experiments were conducted on a steel (Fe-22Mn-0.65C, wt%) with twinning-induced plasticity (TWIP), which was selected for its large grain size and sensitivity to different surface preparation methods. By grouping the results obtained from each nanoindent, chemical polishing was found to be the best sample preparation method with respect to the resulting mechanical properties of the material. In contrast, the presence of a deformation layer left by mechanical polishing and surface damage induced by focused ion beam (FIB) scanning were confirmed by the dislocation-nucleation-induced pop-in events of nanoindentation.
      PubDate: 2021-05-01
       
  • New insights into the properties of high-manganese steel
    • Abstract: In the Collaborative Research Centre 761’s “Steel ab initio - quantum mechanics guided design of new Fe based materials,” scientists and engineers from RWTH Aachen University and the Max Planck Institute for Iron Research conducted research on mechanism-controlled material development with a particular focus on high-manganese alloyed steels. From 2007 to 2019, a total of 55 partial projects and four transfer projects with industrial participation (some running until 2021) have studied material and process design as well as material characterization. The basic idea of the Collaborative Research Centre was to develop a new methodological approach to the design of structural materials. This paper focuses on selected results with respect to the mechanical properties of high-manganese steels, their underlying physical phenomena, and the specific characterization and modeling tools used for this new class of materials. These steels have microstructures that require characterization by the use of modern methods at the nm-scale. Along the process routes, the generation of segregations must be taken into account. Finally, the mechanical properties show a characteristic temperature dependence and peculiarities in their fracture behavior. The mechanical properties and especially bake hardening are affected by short-range ordering phenomena. The strain hardening can be adjusted in a never-before-possible range, which makes these steels attractive for demanding sheet-steel applications.
      PubDate: 2021-05-01
       
  • Medium-Mn steels for hot forming application in the automotive industry
    • Abstract: Advanced high-strength steels have been widely used to improve the crashworthiness and lightweight of vehicles. Different from the popular cold stamping, hot forming of boron-alloyed manganese steels, such as 22MnB5, could produce ultra-high-strength steel parts without springback and with accurate control of dimensions. Moreover, hot-formed medium-Mn steels could have many advantages, including better mechanical properties and lower production cost, over hot-formed 22MnB5. This paper reviews the hot forming process in the automotive industry, hot-formed steel grades, and medium-Mn steel grades and their application in hot forming in depth. In particular, the adaptabilities of medium-Mn steels and the presently popular 22MnB5 into hot forming were compared thoroughly. Future research should focus on the technological issues encountered in hot forming of medium-Mn steels to promote their commercialization.
      PubDate: 2021-05-01
       
  • Micromorphology and safety properties of meager and meager-lean coal for
           blast furnace injection
    • Abstract: Four types of meager and meager-lean coal and one type of high-quality anthracite were selected based on the safety requirements for blast furnace coal injection and domestic coal quality to conduct microstructure and component analyses. The analyses of the organic and inorganic macerals and the chemical compositions of the selected coal samples indicate that the four types of meager and meager-lean coal have low volatilization, low ash content, and low sulfur content; these qualities are suitable for blast furnace injection. Grindability test was conducted on the four types of meager and meager-lean coal and the anthracite mixed coal samples. Results indicate that the mixture of meager and meager-lean coal and anthracite is beneficial to improve the grindability of pulverized coal. The explosive tests reveal that the selected coal samples are non-explosive or weakly explosive. When the proportion of meager and meager-lean coal is less than 40wt%, the mixed coal powder would not explode during the blowing process. The minimum ignition temperature test determines that the minimum ignition temperatures of the four types of meager and meager-lean coal and anthracite are 326, 313, 310, 315, and 393°C, respectively. This study provides a guiding research idea for the safety of meager and meager-lean coal used in blast furnace injection.
      PubDate: 2021-05-01
       
  • Gold-leaching performance and mechanism of sodium dicyanamide
    • Abstract: In this work, sodium dicyanamide (SD) was used as a leaching reagent for gold recovery, and the effects of the SD dosage and solution pH on the gold-leaching performance were investigated. A gold recovery of 34.8% was obtained when SD was used as the sole leaching reagent at a dosage of 15 kg/t. In the presence of a certain amount of potassium ferrocyanide (PF) in the SD solution, the gold recovery was found to increase from 34.8% to 57.08%. Using the quartz crystal microbalance with dissipation (QCM-D) technique, the leaching kinetics of SD with and without PF were studied. The QCM-D results indicate that the gold-leaching rate increased from 4.03 to 39.99 ng·cm−2·min−1 when the SD concentration was increased from 0 to 0.17 mol/L, and increased from 39.99 to 272.62 ng·cm−2·min−1 when 0.1 mol/L of PF was used in combination with SD. The pregnant solution in the leaching tests was characterized by X-ray photoelectron spectroscopy and electrospray mass spectrometry, which indicated that Au and (N(CN)2)− in the SD solution formed a series of metal complex ions, [AuNax(N(CN)2)x+2]− (x = 1, 2, 3, or 4).
      PubDate: 2021-04-07
       
  • Recovery of gold from refractory gold ores: Effect of pyrite on the
           stability of the thiourea leaching system
    • Abstract: The extraction of gold from refractory gold ores (RGOs) without side reactions is an extremely promising endeavor. However, most RGOs contain large amounts of sulfide, such as pyrite. Thus, investigation of the influence of sulfide on the gold leaching process is important to maximize the utilization of RGOs. In this work, the effects of pyrite on the stability of the thiourea system were systematically investigated under different conditions. Results showed that the decomposition rate of thiourea was accelerated sharply in the presence of pyrite. The effect of pyrite on gold recovery in thiourea leaching systems was then confirmed via a series of experiments. The decomposition efficiency of thiourea decreased by 40% and the recovery efficiency of gold increased by 56% after the removal of sulfide by roasting. Under optimal conditions, the efficiency of the gold recovery system increased to 83.69% and only 57.92% of thiourea decomposition was observed. The high consumption of thiourea by the leaching system may be attributed to not only adsorption by mineral particles but also catalytic decomposition by some impurities in the ores, such as pyrite and soluble ferric oxide.
      PubDate: 2021-04-05
       
  • Electrochemical derusting in molten Na 2 CO 3 -K 2 CO 3
    • Abstract: The formation of a rust layer on iron and steels surfaces accelerates their degradation and eventually causes material failure. In addition to fabricating a protective layer or using a sacrificial anode, repairing or removing the rust layer is another way to reduce the corrosion rate and extend the lifespans of iron and steels. Herein, an electrochemical healing approach was employed to repair the rust layer in molten Na2CO3-K2CO3. The rusty layers on iron rods and screws were electrochemically converted to iron in only several minutes and a metallic luster appeared. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses showed that the structures of the rust layer after healing were slightly porous and the oxygen content reached a very low level. Thus, high-temperature molten-salt electrolysis may be an effective way to metalize iron rust of various shapes and structures in a short time, and could be used in the repair of cultural relics and even preparing a three-dimensional porous structures for other applications.
      PubDate: 2021-04-01
       
  • Review on cyclic plasticity of magnesium alloys: Experiments and
           constitutive models
    • Abstract: Fatigue analysis has always been a concern in the design and assessment of Mg alloy structure components subjected to cyclic loading, and research on the cyclic plasticity is fundamental to investigate the corresponding fatigue failure. Thus, this work reviews the progress in the cyclic plasticity of Mg alloys. First, the existing macroscopic and microscopic experimental results of Mg alloys are summarized. Then, corresponding macroscopic phenomenological constitutive models and crystal plasticity-based models are reviewed. Finally, some conclusions and recommended topics on the cyclic plasticity of Mg alloys are provided to boost the further development and application of Mg alloys.
      PubDate: 2021-04-01
       
 
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