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Metals, Volume 7, Issue 8 (August 2017)

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Open AccessArticle Crystallization and Beneficiation of Magnetite for Iron Recycling from Nickel Slags by Oxidation-Magnetic Separation
Metals 2017, 7(8), 321; https://doi.org/10.3390/met7080321
Received: 22 June 2017 / Revised: 11 August 2017 / Accepted: 18 August 2017 / Published: 22 August 2017
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Abstract
The iron resources in nickel slag were recycled by oxidation and magnetic separation. The effects of holding time, temperature, air flow rate and basicity on the crystallization of magnetite were investigated systematically. Moreover, the influence of particle size and magnetic flux density on
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The iron resources in nickel slag were recycled by oxidation and magnetic separation. The effects of holding time, temperature, air flow rate and basicity on the crystallization of magnetite were investigated systematically. Moreover, the influence of particle size and magnetic flux density on the recovery and grade of iron during the magnetic separation was also explored. Results showed that the magnetite particles were significantly influenced by holding time, and the average diameter size reached about 20 μm after holding for 20 min at 1623 K. The holding temperature obviously affected the microstructure of magnetite phases: with the increase in holding temperature, the shapes of the magnetite particles changed from polyhedral form to skeletal particles. As the air flow rate was increased to 170 mL/min, the magnetite developed into tiny spherical particles due to the strong stirring. It was also found that the crystallization of magnetite was slightly effected by basicity. The iron recovery reduced with the decrease of particle size, while the iron grade first increased to a maximal value of 38 μm, and then decreased. As the magnetic flux density increased, the iron recovery initially increased rapidly, reaching a maximal value at 120 mT, while the iron grade remained almost constant. The final iron recovery and grade were 75.99% and 54.08%, respectively, via multi-step magnetic separation instead of single magnetic separation. Iron in concentrate mainly exists in the form of magnetite and magnesium ferrite, and contents of siderophile elements (Ni, Co) in final concentrate were also higher than that of raw slags. Full article
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Open AccessArticle Effects of Alloying Elements (Mo, Ni, and Cu) on the Austemperability of GGG-60 Ductile Cast Iron
Metals 2017, 7(8), 320; https://doi.org/10.3390/met7080320
Received: 22 June 2017 / Revised: 11 August 2017 / Accepted: 15 August 2017 / Published: 22 August 2017
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Abstract
The interest in austempered ductile irons (ADI) is continuously increasing due to their various advantageous properties over conventional ductile irons and some steels. This study aimed to determine the roles of alloying elements Ni, Cu, and Mo, on the austemperability of GGG-60 ductile
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The interest in austempered ductile irons (ADI) is continuously increasing due to their various advantageous properties over conventional ductile irons and some steels. This study aimed to determine the roles of alloying elements Ni, Cu, and Mo, on the austemperability of GGG-60 ductile cast iron. Two different sets of GGG-60 (EN-GJS-600-3) samples, one set alloyed with Ni and Cu and the other set alloyed with Mo, Ni, and Cu, were subjected to austempering treatments at 290 °C, 320 °C, and 350 °C. A custom design heat treatment setup, consisting of two units with the top unit (furnace) serving for austenitizing and the 200 L capacity bottom unit (stirred NaNO2-KNO3 salt bath) serving for isothermal treatment, was used for the experiments. It was found that austempering treatment at 290 °C increased the hardness of the Ni-Cu alloyed GGG-60 sample by about 44% without causing a loss in its ductility. In the case of the Mo-Ni-Cu alloyed sample, the increase in hardness due to austempering reached to almost 80% at the same temperature while some ductility was lost. Here, the microstructural investigation and mechanical testing results of the austempered samples are presented and the role of alloying elements (Mo, Ni, and Cu) on the austemperability of GGG-60 is discussed. Full article
(This article belongs to the Special Issue Selected Papers from the 3rd International Iron and Steel Symposium)
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Open AccessArticle Study on Hot Deformation Behavior and Microstructure Evolution of Ti55 High-Temperature Titanium Alloy
Metals 2017, 7(8), 319; https://doi.org/10.3390/met7080319
Received: 29 June 2017 / Revised: 2 August 2017 / Accepted: 11 August 2017 / Published: 20 August 2017
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Abstract
The isothermal compression experiment of as-rolled Ti55 alloy was carried out on a Gleeble-3800 thermal simulation test machine at the deformation temperature range of 700–1050 °C and strain rate range of 0.001–1 s−1. The hot deformation behavior and the microstructure evolution
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The isothermal compression experiment of as-rolled Ti55 alloy was carried out on a Gleeble-3800 thermal simulation test machine at the deformation temperature range of 700–1050 °C and strain rate range of 0.001–1 s−1. The hot deformation behavior and the microstructure evolution were analyzed during thermal compression. The results show that the apparent activation energy Q in α+β dual-phase region and β single-phase region were calculated to be 453.00 KJ/mol and 279.88 KJ/mol, respectively. The deformation softening mechanism was mainly controlled by dynamic recrystallization of α phase and dynamic recovery of β phase. Discontinuous yielding behavior mainly occurred in β phase region, which weakened gradually with the increase of deformation temperature (>990 °C) and strain rate (0.01–1 s−1) in β phase region. The processing map derived from Murty’s criterion was more accurate in predicting the hot workability than that derived from Prasad’s criterion. The optimized hot working window was 850–975°C/0.001–1 s−1, in which sufficient dynamic recrystallization occurred and α + β-transus microstructure was obtained. When deformed at higher temperature (≥1000 °C), coarsened lath-shape β-transus microstructure was formed, while deformed at lower temperature (≤825 °C) and higher strain rate (≥0.1 s−1), the dynamic recrystallization was not sufficient, thus flow instability appeared because of shear cracking. Full article
(This article belongs to the Special Issue Titanium Alloys 2017)
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Open AccessArticle Influence of Build Orientation, Heat Treatment, and Laser Power on the Hardness of Ti6Al4V Manufactured Using the DMLS Process
Metals 2017, 7(8), 318; https://doi.org/10.3390/met7080318
Received: 20 July 2017 / Revised: 10 August 2017 / Accepted: 11 August 2017 / Published: 18 August 2017
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Abstract
This contribution is focused on the influence of build orientation on hardness of materials sintered using direct metal laser sintering (DMLS) technology. It builds on the current research works that has monitored the influence of build orientation on a fatigue life, mechanical properties,
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This contribution is focused on the influence of build orientation on hardness of materials sintered using direct metal laser sintering (DMLS) technology. It builds on the current research works that has monitored the influence of build orientation on a fatigue life, mechanical properties, roughness after machining, etc. In the mentioned work, a slight influence of build orientation on the above properties was shown. The hardness was measured on a Ti6Al4V alloy which was made of powder by DMLS technology. The individual materials were sintered at different laser powers, then annealed to remove internal stresses. Part of the experiment examined the metallographic analysis of materials in the direction perpendicular to the sintered layers and parallel with the sintered layers. Microhardness was measured on metallographic cross-sections and the results were statistically processed. The influence of laser power on a respective material hardness was assessed by one-way analysis of variance (ANOVA), a comparison of the hardness between sintered and sintered-annealed samples, as well as the comparison of hardness in the two considered directions was performed by t-test and F-test. A statistically significant difference in the hardness of the materials prepared at different laser powers was found. The influence of heat treatment, as well as the direction of material building also showed a statistically significant difference. Full article
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Open AccessArticle First-Principles Investigation of Structural, Electronic and Elastic Properties of HfX (X = Os, Ir and Pt) Compounds
Metals 2017, 7(8), 317; https://doi.org/10.3390/met7080317
Received: 12 July 2017 / Revised: 9 August 2017 / Accepted: 10 August 2017 / Published: 18 August 2017
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Abstract
The structural, electronic and elastic properties of B2 structure Hafnium compounds were investigated by means of first-principles calculations based on the density functional theory within generalized gradient approximation (GGA) and local density approximation (LDA) methods. Both GGA and LDA methods can make acceptable
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The structural, electronic and elastic properties of B2 structure Hafnium compounds were investigated by means of first-principles calculations based on the density functional theory within generalized gradient approximation (GGA) and local density approximation (LDA) methods. Both GGA and LDA methods can make acceptable optimized lattice parameters in comparison with experimental parameters. Therefore, both GGA and LDA methods are used to predict the electronic and elastic properties of B2 HfX (X = Os, Ir and Pt) compounds. Initially, the calculated formation enthalpies have confirmed the order of thermodynamic stability as HfPt > HfIr > HfOs. Secondly, the electronic structures are analyzed to explain the bonding characters and stabilities in these compounds. Furthermore, the calculated elastic properties and elastic anisotropic behaviors are ordered and analyzed in these compounds. The calculated bulk moduli are in the reduced order of HfOs > HfIr > HfPt, which has exhibited the linear relationship with electron densities. Finally, the anisotropy of acoustic velocities, Debye temperatures and thermal conductivities are obtained and discussed. Full article
(This article belongs to the Special Issue First-Principles Approaches to Metals, Alloys, and Metallic Compounds)
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Open AccessArticle Study on Microstructure and Properties of Bimodal Structured Ultrafine-Grained Ferrite Steel
Metals 2017, 7(8), 316; https://doi.org/10.3390/met7080316
Received: 24 June 2017 / Revised: 3 August 2017 / Accepted: 16 August 2017 / Published: 18 August 2017
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Abstract
The objective of the study research was to obtain bimodal structured ultrafine-grained ferrite steel with outstanding mechanical properties and excellent corrosion resistance. The bimodal microstructure was fabricated by the cold rolling and annealing process of a dual-phase steel. The influences of the annealing
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The objective of the study research was to obtain bimodal structured ultrafine-grained ferrite steel with outstanding mechanical properties and excellent corrosion resistance. The bimodal microstructure was fabricated by the cold rolling and annealing process of a dual-phase steel. The influences of the annealing process on microstructure evolution and the mechanical properties of the cold-rolled dual-phase steel were investigated. The effect of bimodal microstructure on corrosion resistance was also studied. The results showed that the bimodal characteristic of ferrite steel was most apparent in cold-rolled samples annealed at 650 °C for 40 min. More importantly, due to the coordinated action of fine-grained strengthening, back-stress strengthening, and precipitation strengthening, the yield strength (517 MPa) of the bimodal microstructure improved significantly, while the total elongation remained at a high level of 26%. The results of corrosion experiments showed that the corrosion resistance of bimodal ferrite steel was better than that of dual-phase steel with the same composition. This was mainly because the Volta potential difference of bimodal ferrite steel was smaller than that of dual-phase steel, which was conducive to forming a protective rust layer. Full article
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Open AccessErratum Erratum: Structure, Texture and Phases in 3D Printed IN718 Alloy Subjected to Homogenization and HIP Treatments. Metals 2017, 7, 196
Metals 2017, 7(8), 315; https://doi.org/10.3390/met7080315
Received: 2 August 2017 / Revised: 3 August 2017 / Accepted: 7 August 2017 / Published: 16 August 2017
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Abstract
The authors wish to make the following corrections to the main text in the published paper [1]. In this paper, the weight of CuCl2 should be changed from 5 mg to 5 g to provide accurate recipe for the IN718 etchant.[...] Full article
(This article belongs to the Special Issue Selective Laser Melting)
Open AccessArticle Broadband Dual-Phase Plasmons through Metallization of Polymeric Heterojunctions
Metals 2017, 7(8), 314; https://doi.org/10.3390/met7080314
Received: 1 July 2017 / Revised: 1 August 2017 / Accepted: 12 August 2017 / Published: 16 August 2017
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Abstract
Large-area dual-phase plasmonic gold nanostructures were produced using the phase-separation pattern of a polymer blend film, where two typical light-emitting polymeric semiconductors of poly (9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) and poly (9,9-dioctylfluorene-co-bis-N,N′-(4-butylphenyl)-bis-N,N′-phenyl-1,4 phenylenediamine) (PFB)
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Large-area dual-phase plasmonic gold nanostructures were produced using the phase-separation pattern of a polymer blend film, where two typical light-emitting polymeric semiconductors of poly (9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) and poly (9,9-dioctylfluorene-co-bis-N,N′-(4-butylphenyl)-bis-N,N′-phenyl-1,4 phenylenediamine) (PFB) have been employed to construct the heterojunction patterns. The laser-induced selective cross-linking of F8BT molecules and the subsequent rinsing process using the good solvent of chloroform for PFB supplies a stable template for a further metallization process. When colloidal gold nanoparticles were spin-coated onto the surface of the template, a majority of the gold nanoparticles were confined into the “holes” of originally PFB-rich phase, while a minor portion stays on the “ridges” of F8BT-rich phase. After the annealing process, larger gold nanoparticles were produced inside the holes and smaller ones on the ridges, which induced localized surface plasmon resonance in the near infrared and in the visible, respectively. The structural parameters of the gold plasmonic pattern can be tuned by different surface modification and annealing processes, which can tune the spectroscopic response in the spectral position and in the spectral intensity. The produced nanostructures with broadband plasmon resonance can be used as a template for random lasers with strong optical scattering at both the pump and emission wavelengths and for photovoltaic devices with strong absorption in the visible and near infrared. Full article
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Open AccessArticle Preparing Ferro-Nickel Alloy from Low-Grade Laterite Nickel Ore Based on Metallized Reduction–Magnetic Separation
Metals 2017, 7(8), 313; https://doi.org/10.3390/met7080313
Received: 9 July 2017 / Revised: 9 August 2017 / Accepted: 12 August 2017 / Published: 16 August 2017
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Abstract
Nickel, a valued metal, mainly exists as nickel oxide in laterite nickel ore. Furthermore, a large part of the laterite nickel ore is low-grade saprolitic ore. In this paper, a research on preparing ferro-nickel alloy from low-grade saprolitic laterite nickel ore using metallized
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Nickel, a valued metal, mainly exists as nickel oxide in laterite nickel ore. Furthermore, a large part of the laterite nickel ore is low-grade saprolitic ore. In this paper, a research on preparing ferro-nickel alloy from low-grade saprolitic laterite nickel ore using metallized reduction-magnetic separation was studied. In the research, the carbothermic reductions of iron oxide and nickel oxide were analyzed in terms of thermodynamics. The influences of reduction temperature, reduction time, carbon ratio, and CaO addition on the recoveries and grades of iron and nickel were experimentally investigated. To analyze and clarify the related mechanism, the microstructure of ferro-nickel alloy was observed by optical microscope (OM) and scanning electron microscope/energy dispersive spectrometer (SEM/EDS). Accordingly, the results showed that, increasing reduction temperature can improve the grades and recoveries of nickel and iron; appropriate reduction time, carbon ratio and CaO addition can favor aggregation and growing up of the ferro-nickel particles, improving the grades and recoveries of nickel and iron. The optimal process parameters obtained were a reduction temperature of 1350 °C, reduction time of 2 h, carbon ratio of 1.2, and CaO addition of 10%. In this case, the ferro-nickel alloy with nickel grade 7.90% and iron grade 77.32% was prepared successfully from the low-grade saprolitic ore with nickel content 1.82%. The nickel and iron recoveries were 89.36% and 95.87% respectively, which achieved the highly efficient recovery and utilization of iron and nickel of low-grade laterite nickel ore. Full article
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Open AccessArticle Statistical Analysis and Fatigue Life Estimations for Quenched and Tempered Steel at Different Tempering Temperatures
Metals 2017, 7(8), 312; https://doi.org/10.3390/met7080312
Received: 6 July 2017 / Revised: 8 August 2017 / Accepted: 9 August 2017 / Published: 16 August 2017
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Abstract
In this paper, the statistical properties and fatigue life estimations of 0.44% carbon steel at different tempering temperatures are presented. The specimens were austenized at 900 °C for 10 min, quenched in water, tempered at different temperatures, and then machined to the design
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In this paper, the statistical properties and fatigue life estimations of 0.44% carbon steel at different tempering temperatures are presented. The specimens were austenized at 900 °C for 10 min, quenched in water, tempered at different temperatures, and then machined to the design geometry and average surface roughness of Ra = 0.4 μm. The effect of tempering temperature on the fatigue life of 0.44% carbon steel was investigated using 75 fatigue tests, divided into three groups at temperatures 500 °C, 600 °C, and 700 °C. S–N and P–S–N curves were established. Two methods of estimating the mean fatigue life are presented. One is based on dislocation dipole accumulation and Paris’ law; another is based on the kriging model. Six more fatigue tests were carried out to validate the presented methods. Test results showed that the first method is superior to the second in terms of estimating accuracy from the validation datum. However, the second method could estimate the mean fatigue life of quenched and tempered 0.44% carbon steel with an average surface roughness of Ra = 0.4 μm when the tempering temperature was set to a value other than 500 °C, 600 °C, or 700 °C, with no additional fatigue test needed. Full article
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Open AccessArticle An Algorithm for Surface Defect Identification of Steel Plates Based on Genetic Algorithm and Extreme Learning Machine
Metals 2017, 7(8), 311; https://doi.org/10.3390/met7080311
Received: 30 June 2017 / Revised: 5 August 2017 / Accepted: 8 August 2017 / Published: 15 August 2017
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Abstract
Defects on the surface of steel plates are one of the most important factors affecting the quality of steel plates. It is of great importance to detect such defects through online surface inspection systems, whose ability of defect identification comes from self-learning through
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Defects on the surface of steel plates are one of the most important factors affecting the quality of steel plates. It is of great importance to detect such defects through online surface inspection systems, whose ability of defect identification comes from self-learning through training samples. Extreme Learning Machine (ELM) is a fast machine learning algorithm with a high accuracy of identification. ELM is implemented by a hidden matrix generated with random initialization parameters, while different parameters usually result in different performances. To solve this problem, an improved ELM algorithm combined with a Genetic Algorithm was proposed and applied for the surface defect identification of hot rolled steel plates. The output matrix of the ELM’s hidden layers was treated as a chromosome, and some novel iteration rules were added. The algorithm was tested with 1675 samples of hot rolled steel plates, including pockmarks, chaps, scars, longitudinal cracks, longitudinal scratches, scales, transverse cracks, transverse scratches, and roll marks. The results showed that the highest identification accuracies for the training and the testing set obtained by the G-ELM (Genetic Extreme Learning Machine) algorithm were 98.46% and 94.30%, respectively, which were about 5% higher than those obtained by the ELM algorithm. Full article
(This article belongs to the Special Issue Researches and Simulations in Steel Rolling)
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Open AccessArticle Microstructure and Strengthening-Toughening Mechanism of Nitrogen-Alloyed 4Cr5Mo2V Hot-Working Die Steel
Metals 2017, 7(8), 310; https://doi.org/10.3390/met7080310
Received: 27 June 2017 / Revised: 8 August 2017 / Accepted: 10 August 2017 / Published: 14 August 2017
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Abstract
The microstructure and strengthening-toughening mechanism of a modified 4Cr5Mo2V hot-working die steel with nitrogen (0.08% N) were investigated using hardness and toughness measurements, optical microscopy, scanning electron microscopy, X-ray diffraction experiments, transmission electron microscopy, and dilatometry. The results showed that the nitrogen addition
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The microstructure and strengthening-toughening mechanism of a modified 4Cr5Mo2V hot-working die steel with nitrogen (0.08% N) were investigated using hardness and toughness measurements, optical microscopy, scanning electron microscopy, X-ray diffraction experiments, transmission electron microscopy, and dilatometry. The results showed that the nitrogen addition could increase the hardness and temperability of 4Cr5Mo2V steel without toughness loss with a suitable heat treatment procedure. The fair match of high strength and toughness of the nitrogen-alloyed 4Cr5Mo2V steel is associated with the refinement of the prior austenite grain, the solution hardening of nitrogen atoms, and the increase of retained austenite. Before quenching, nitrogen tends to precipitate in the form of a large amount of undissolved finer V(C, N), imposing a stronger effect on restricting the growth of prior austenitic grains and increasing the grain refining efficiency of VC by 6.8 times according to an estimate. During the quenching process, the nitrogen decreases the MS of the martensitic transformation, increasing retained austenite, which is a benefit for toughness. During the tempering process, some of the N atoms in M(C, N) were dissolved in the matrix, causing crystal lattice distortions, thus boosting the solution reinforcing effect. Meanwhile, the solid-dissolved nitrogen inhibits the diffusion of carbon, decreasing the growth rate of the carbides and increasing tempering resistance. Full article
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Open AccessArticle Microstructure, Mechanical Property, and Phase Transformation of Quaternary NiTiFeNb and NiTiFeTa Shape Memory Alloys
Metals 2017, 7(8), 309; https://doi.org/10.3390/met7080309
Received: 3 July 2017 / Revised: 31 July 2017 / Accepted: 9 August 2017 / Published: 12 August 2017
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Abstract
Based on ternary Ni45Ti51.8Fe3.2 (at %) shape memory alloy (SMA), Nb and Ta elements are added to an NiTiFe SMA by replacing Ni element, and consequently quaternary Ni44Ti51.8Fe3.2Nb1 and Ni44
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Based on ternary Ni45Ti51.8Fe3.2 (at %) shape memory alloy (SMA), Nb and Ta elements are added to an NiTiFe SMA by replacing Ni element, and consequently quaternary Ni44Ti51.8Fe3.2Nb1 and Ni44Ti51.8Fe3.2Ta1 (at %) SMAs are fabricated. The microstructure, mechanical property, and phase transformation of NiTiFeNb and NiTiFeTa SMAs are further investigated. Ti2Ni and β-Nb phases can be observed in NiTiFeNb SMA, whereas Ti2Ni and Ni3Ti phases can be captured in NiTiFeTa SMA. As compared to NiTiFe SMA, quaternary NiTiFeNb and NiTiFeTa SMAs possess the higher strength, since solution strengthening plays a considerable role. NiTiFeNb and NiTiFeTa SMAs exhibit a one-step transformation from B2 austenite to B19’ martensite during cooling, but they experience a two-step transformation of B19’-R-B2 during heating. Full article
(This article belongs to the Special Issue Shape Memory Alloys 2017) Printed Edition available
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Open AccessArticle Surface Characterization and Corrosion Resistance of 36Cr-Ni-Mo4 Steel Coated by WC-Co Cermet Electrode Using Micro-Electro Welding
Metals 2017, 7(8), 308; https://doi.org/10.3390/met7080308
Received: 5 July 2017 / Revised: 24 July 2017 / Accepted: 25 July 2017 / Published: 12 August 2017
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Abstract
In this paper the influence of spark energy on corrosion resistance, hardness, surface roughness and morphology of WC-Co coated 36Cr-Ni-Mo4 steel by Micro-Electro Welding (MEW) was investigated. Frequencies of 5, 8 and 11 kHz, currents of 15, 25 and 35 A and duty
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In this paper the influence of spark energy on corrosion resistance, hardness, surface roughness and morphology of WC-Co coated 36Cr-Ni-Mo4 steel by Micro-Electro Welding (MEW) was investigated. Frequencies of 5, 8 and 11 kHz, currents of 15, 25 and 35 A and duty cycles of 10, 30 and 50 % were applied for coating of the samples using a WC-Co cermet electrode. The results indicate that increasing the current, Duty cycle and frequency of the process increases spark energy. As spark energy increases, efficiency of coating increases to 80% and then decreases. X-ray diffraction (XRD) analysis was used to identify the phases. The results indicated that other than the peaks obtained for the metallic Iron with BCC (Body Centered Cubic) structure, Tungsten Carbide, Cr7C3 and Titanium Carbide phases were also seen on the surface. Vickers micro hardness method was used for hardness measurement of the samples. Surface hardness increases to 817.33 HV0.05 with spark energy increasing up to 1.03 mJ, and then reducing. Optical Microscopy (OM) and scanning electron microscopy (SEM) to study Microstructural and atomic force microscopy (AFM) to study the topography, morphology and roughness were used. Polarization technique in 3.5 wt % NaCl solution was used to evaluate the corrosion properties. The results of the energy dispersive X-ray spectroscopy (EDS) analysis indicate that with increasing spark energy, the amount of Tungsten in surface increases to 41.95 wt % and then decreases. As spark energy increases up to 2.17 mJ, thickness of coating increases to 8.31 μm and then decreases. As spark energy increases, surface roughness is also increased. Corrosion test results indicated that the lowest corrosion rate (2.6 × 10−8 mpy) is related to the sample with the highest level of efficiency. Full article
(This article belongs to the Special Issue Cermets and Hardmetals)
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Open AccessArticle FEM Simulation of Dissimilar Aluminum Titanium Fiber Laser Welding Using 2D and 3D Gaussian Heat Sources
Metals 2017, 7(8), 307; https://doi.org/10.3390/met7080307
Received: 1 June 2017 / Revised: 2 August 2017 / Accepted: 8 August 2017 / Published: 10 August 2017
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Abstract
For a dissimilar laser weld, the model of the heat source is a paramount boundary condition for the prediction of the thermal phenomena, which occur during the welding cycle. In this paper, both two-dimensional (2D) and three-dimensional (3D) Gaussian heat sources were studied
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For a dissimilar laser weld, the model of the heat source is a paramount boundary condition for the prediction of the thermal phenomena, which occur during the welding cycle. In this paper, both two-dimensional (2D) and three-dimensional (3D) Gaussian heat sources were studied for the thermal analysis of the fiber laser welding of titanium and aluminum dissimilar butt joint. The models were calibrated comparing the fusion zone of the experiment with that of the numerical model. The actual temperature during the welding cycle was registered by a thermocouple and used for validation of the numerical model. When it came to calculate the fusion zone dimensions in the transversal section, the 2D heat source showed more accurate results. The 3D heat source provided better results for the simulated weld pool and cooling rate. Full article
(This article belongs to the Special Issue Laser Welding)
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