Subjects -> METALLURGY (Total: 59 journals)
 Showing 1 - 10 of 10 Journals sorted alphabetically Acta Metallurgica Slovaca       (Followers: 2) Advanced Device Materials       (Followers: 6) American Journal of Fluid Dynamics       (Followers: 44) Archives of Metallurgy and Materials       (Followers: 9) Asian Journal of Materials Science       (Followers: 4) Canadian Metallurgical Quarterly       (Followers: 21) Complex Metals       (Followers: 2) Energy Materials : Materials Science and Engineering for Energy Systems       (Followers: 24) Graphene and 2D Materials       (Followers: 6) Handbook of Ferromagnetic Materials       (Followers: 1) Handbook of Magnetic Materials       (Followers: 2) High Temperature Materials and Processes       (Followers: 6) Indian Journal of Engineering and Materials Sciences (IJEMS)       (Followers: 11) International Journal of Metallurgy and Alloys       (Followers: 2) International Journal of Metals       (Followers: 7) International Journal of Minerals, Metallurgy, and Materials       (Followers: 12) International Journal of Mining and Geo-Engineering       (Followers: 4) Ironmaking & Steelmaking       (Followers: 5) ISIJ International - Iron and Steel Institute of Japan       (Followers: 26) Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Proceedings of Higher Schools. Powder Metallurgy аnd Functional Coatings)       (Followers: 2) JOM Journal of the Minerals, Metals and Materials Society       (Followers: 35) Journal of Advanced Joining Processes Journal of Central South University       (Followers: 1) Journal of Cluster Science Journal of Heavy Metal Toxicity and Diseases Journal of Iron and Steel Research International       (Followers: 11) Journal of Materials & Metallurgical Engineering       (Followers: 2) Journal of Materials Processing Technology       (Followers: 21) Journal of Metallurgical Engineering       (Followers: 4) Journal of Sustainable Metallurgy       (Followers: 3) Materials Science and Metallurgy Engineering       (Followers: 7) Metal Finishing       (Followers: 20) Metallurgical and Materials Engineering       (Followers: 7) Metallurgical and Materials Transactions A       (Followers: 42) Metallurgical and Materials Transactions B       (Followers: 32) Metallurgical and Materials Transactions E       (Followers: 2) Metallurgical Research & Technology Metallurgical Research and Technology       (Followers: 8) Metallurgy and Foundry Engineering       (Followers: 3) Mining, Metallurgy & Exploration Powder Diffraction       (Followers: 1) Powder Metallurgy       (Followers: 35) Powder Metallurgy and Metal Ceramics       (Followers: 7) Powder Metallurgy Progress       (Followers: 5) Practical Metallography       (Followers: 6) Rare Metals       (Followers: 3) Revista de Metalurgia Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica Revista Remetallica       (Followers: 1) Russian Metallurgy (Metally)       (Followers: 4) Science and Technology of Welding and Joining       (Followers: 8) Soldering & Surface Mount Technology       (Followers: 2) Steel Times lnternational       (Followers: 19) Transactions of the IMF       (Followers: 14) Transactions of the Indian Institute of Metals       (Followers: 5) Tungsten Universal Journal of Materials Science       (Followers: 3) Welding in the World       (Followers: 8) Welding International       (Followers: 11) Вісник Приазовського Державного Технічного Університету. Серія: Технічні науки
Similar Journals
 Transactions of the Indian Institute of MetalsJournal Prestige (SJR): 0.361 Citation Impact (citeScore): 1Number of Followers: 5      Hybrid journal (It can contain Open Access articles) ISSN (Print) 0972-2815 - ISSN (Online) 0975-1645 Published by Springer-Verlag  [2656 journals]
• Inter-Columnar Macro-Segregation in Continuously Cast Steel;
Characterization, Possible Reasons, and Consequences
• Abstract: The current work emphasizes the characterization of inter-columnar macro-segregation in as-cast samples from continuously cast steel slabs and their segregation level in the rolled products. Based on the literature studies, and understanding from the characterization of steel samples, the formation mechanism and possible causes of inter-columnar segregation have been elucidated. It is observed that macro-segregation happens as a result of the breakage of columnar dendrites in the low ductility region of steel between zero ductile temperature (ZDT) and zero strength temperature (ZST). The external tensile strain has been observed in the form of strain rate due to the cumulative strain of bulging, straightening, and misalignment which exceeds the critical strain of steel causing crack formation at the low ductility region. The inherent critical strain is determined from the interval of ZDT and ZST region which is decided by the segregation of solute elements based on the steel composition. To some extent, the current work elucidates the effect of solute elements on the critical strain and most importantly on segregation of sulphur and phosphorus in liquid has been simulated using Scheil solidification model in Thermo-Calc software. However, the segregation of sulphur leads to the formation of manganese sulphide, whereas steels having a phosphorus level of more than 0.016% enhance the crack formation resulting in inter-columnar segregation, which is in good agreement with the plant data and experimental studies with other researchers.
PubDate: 2021-05-03

• Coupled Mathematical Model of Thermal Stress for Initial Shell of Groove
Continuous Casting Mold
• Abstract: In this paper, the coupled mathematical model of thermal stress is established for initial shell of the groove mold and slab mold. The shape, temperature and stress field of initial shell are calculated. The results show that the wave crest and trough corresponding to the air gap of the groove are formed in the initial shell of the groove mold, and the difference between wave crest and trough decreases with the increase in the thickness of the initial shell, and the nonuniformity of the shell is lower than that of the flat mold, and the stress value of the initial shell is about 1/10 of the flat mold, and the distribution is uniform. The temperature of the shell surface of groove mold is higher than that of flat mold. Compared with flat mold, groove mold can reduce the surface stress of initial billet shell and improve the surface quality of billet.
PubDate: 2021-04-29

• Microstructure and Phase Analysis of Multilayer Ni–Cr–Mo Clad
for Corrosion Protection
• Abstract: Ni–Cr–Mo clads are commonly used on carbon steels in the oil and gas industry due to the high resistant corrosion. In this study, a three-layer Ni–Cr–Mo clad was deposited using the GMAW process. The welding current of 200 A, the welding speed of 35 cm/min, and the electrode extension of 20 mm, as well as the torch angle of 25°, are utilized to obtain a low dilution. The results showed that Fe content in the second and third layers of the clad was below 2 wt%. The segregation of Nb and Mo to interdendritic regions contributed to the formation of secondary phases, such as Laves and MC carbide precipitates. The results of chemical analysis across some dendrites and interdendritic regions confirmed that the contents and distribution of secondary phases were insignificant. Also, the transition region where the chemical composition significantly changes to reach the composition of the first layer of the clad is apparent. The microstructure of this region changes from the planar to cellular. The corrosion behavior of the clad was investigated, and it was found that corrosion resistance is not affected when the Fe content is restricted to below 2%. A passive layer consisting of Mo, Nb, Ni and Cr with O is formed on the corroded surface.
PubDate: 2021-04-29

• Studies on Super Duplex Stainless Steel Manufactured by Wire Arc Additive
Manufacturing
• Abstract: The oil and gas industries have been extensively utilizing 25Cr super duplex stainless steels because of their excellent mechanical properties and corrosion resistance. Wire arc additive manufacturing technology was employed to fabricate thin wall using ER2594 filler wire. The microstructural examination exposed the presence of ferrite, intragranular austenite, Widmanstätten austenite, grain-boundary austenite and secondary austenite. It was found that the austenite-ferrite fraction varied across the wall due to the complex cyclic thermal history during deposition. Detrimental phases such as sigma-σ or lambda-λ were not observed due to lower heat input and suitable inter-pass temperature. Micro-hardness measurements showed the gradual variation of hardness along the built direction (281–310HV0.2). Tensile specimens exposed anisotropy, and the tensile properties were better than the wrought counterparts and meet the minimum requirements as mentioned in ASTM A240/A240M-20a and ANSI/NACE MR0175/ISO 15156-1:2015.
PubDate: 2021-04-29

• Dephosphorization of Hot Metal Containing High Phosphorus Using F-free
CaO–SiO 2 –Al 2 O 3 –Fe 2 O 3 Slag
• Abstract: With the extensive usage of domestic low-grade iron ore with high phosphorus, abundant high (> 0.35%) phosphorus hot metal generates in China. To solve the dephosphorization issue of high-P hot metal under the premise of avoiding the environmental problem caused by CaF2 flux agent, a type of F-free CaO–SiO2–Al2O3–Fe2O3 slag was designed for the dephosphorization of high-P hot metal and systematically tested and analyzed combined with FactSage software under 1400 °C in this paper. The results show that it is an effective approach to remove phosphorus from hot metal-containing high phosphorus using F-free CaO–SiO2–Al2O3–Fe2O3 slag. The major driving force for this dephosphorization comes from the precipitation of $${\text{Ca}}_{{2}} {\text{SiO}}_{{4}} \cdot n{\text{Ca}}_{{3}} {\text{(PO}}_{{4}}^{{}} {)}_{{2}}$$ (C2S-C3P) phase which lowers the activity of phosphorus in liquid slag by providing a site to stabilize phosphorus in slag. The increase of basicity enhances the dephosphorization process by promoting the precipitation of the P-rich C2S-C3P phase. The Fe2O3 in slag favors the removal of phosphorus from hot metal-containing high phosphorus using CaO–SiO2–Al2O3–Fe2O3 slag by improving the oxidability of slag. The Al2O3 in slag will compete with P2O5 to combine with CaO and SiO2, which inhibits the formation of C2S-C3P and thus weakens the dephosphorization ability of slag.
PubDate: 2021-04-28

• Sustainable Hard Turning of High Chromium AISI D2 Tool Steel Using CBN and
Ceramic Inserts
• Abstract: In this experimental study, the effects of cutting parameters and insert types on the surface roughness and cutting force components were investigated during hard turning of high chromium AISI D2 tool steel under dry cutting conditions. Three different cutting speeds, feed rates, and cutting depths were chosen as machining parameters, while cubic boron nitride and ceramic inserts with two different nose radii were selected as tool material. The design of the experiment was carried out based on the Taguchi L36 mixed orthogonal array. The response surface method was used to establish the relation between input and output parameters. Analysis of variance was performed to show the most significant parameters on the response. In addition, an artificial neural network was implemented for output modeling. The results revealed that surface roughness was mainly affected by the feed rate with almost 90.53%. Following feed rate, the nose radius was also significant on the surface roughness. Based on the results, the cubic boron nitride insert exhibited better performance than the ceramic insert in terms of minimum surface roughness. The cutting force components were mostly affected by the insert type. Cubic boron nitride insert caused greater forces during machining compared to the ceramic insert. The results revealed that the artificial neural network and response surface methodology exhibited very good accuracy with experimental data. However, the artificial neural network shows better accuracy and can predict the responses with 99.51% accuracy.
PubDate: 2021-04-28

• Mechanical and Microstructural Characteristics of Gas Tungsten Arc Welded
Similar and Dissimilar Joints of SS-316 L and Hastelloy C276
• Abstract: Hastelloy C-276 nickel alloy is widely preferred for nuclear power plant applications where steam generators operate at 600 °C. However, stainless steels are still used for tubes in steam gas reformers which necessitates welds between dissimilar materials. In this study, hastelloy C-276 and SS 316 L alloys were joined using GTAW process. The welding parameters of GTAW were optimized to minimize the defects in samples of similar (SS 316 L-SS 316 L, HAS C-276-HAS C-276), and dissimilar (HAS C-276-SS 316 L) joints. SEM/EDS results confirm the presence of columnar dendritic and cellular structure in fusion zone for dissimilar weldments (HAS C-276-SS 316 L). EDS results also revealed the presence of larger amount of Mo, W and lower amount of Ni in the subgrain boundary as compared to the subgrain body. Compared to the similar (HAS C-276- Has C-276) and dissimilar (HAS C-276-SS 316 L) welded joints FZs, the enrichment of Mo is lesser in SS 316 L-SS 316 L similar welded joints. Higher UTS was obtained for dissimilar (HAS C-276-SS 316 L) GTAW joints 780 MPa compared to the similar welded joints of SS316 (552 MPa) and HAS C-276 (740 MPa). The average microhardness for the dissimilar SS 316 L and HAS C-276 is 220 Hv, which is higher compared to the similar welded joints, SS 316 L and HAS C-276, i.e., 190 Hv and 210 Hv, respectively. This study shows that GTAW process is suitable to fabricate sound weld joints of similar (SS 316 L- SS 316 L, HAS C-276-HAS C-276), and dissimilar (HAS C-276-SS 316 L) alloys which are useful for the nuclear power plant boilers.
PubDate: 2021-04-27

• Effect of Mixing Pre-heated Water on Granulation and Iron Ore Sinter
Properties
• Abstract: Granulation of sinter feed mix is one of the most important factors in determining the permeability of sinter bed and sinter properties like sinter yield, tumbler index, etc. To improve the granulation of sinter feed mix, various technologies like two-stage granulation process, coating granulation process, wet vertical ball mill and use of magnetic water have been reported. In this paper, effect of pre-heated water (30, 60 and 90 °C) on granulation fitness of sinter feed mix was studied using a laboratory mixing drum. Sinter properties were investigated using pot sinter experiments. It was observed that with addition of pre-heated water, granulation fitness i.e., Balling index (BI) and Granulation index (GI) has increased, indicating that wetting of sinter feed mix has improved significantly. Treatment of sinter feed mix with pre-heated water reduces the surface tension of water and improves slaking of lime. This enables improved binding of the small size faction (− 0.25 mm), leading to stronger green ball which results in reduced fine generation during charging to the sinter bed. This further leads to the improvement in bed permeability and sinter properties. Enhanced hydration of lime and improved dispersion of water thus achieved have benefitted granulation fitness (GI increases by 5.3% and BI increases by 9.7%). Sinter yield increases by 2.1% and tumbler index by 1.6%. The results suggest that the proposed methodology is effective in improving the granulation fitness of sinter feed mix and sinter properties.
PubDate: 2021-04-27

• Simulation and Application of NO X Emission Characteristics in the
Vertical Flue of 6 m Coke Oven
• Abstract: In view of the formation process of nitrogen oxide in the vertical flue of coke oven, a three-dimensional steady-state mathematical model of heat transfer, mass transfer and combustion process was established, and the numerical method was used to solve the problem. The effects of exhaust gas circulation ratio, preheating temperature of blast furnace gas and air and the blending ratio of coke oven gas on the NOX generation characteristics were studied. The above parameters were further optimized to the model that was applied to 6-m coke oven of Ansteel. The results show that the numerical simulation results are in good agreement with theoretical combustion temperature and the NOX emission data of 6-m coke oven in Ansteel. Through the optimization scheme, the preheating temperature of gas and air is the most significant one, followed by ratio of exhaust gas circulation and coke oven gas blending. The optimized model is applied to 6 m coke oven of Ansteel, and the average content of NOX in the exhaust gas is reduced from 364 to 228 mg/m3, with good effect.
PubDate: 2021-04-21

• Effect of Finish Rolling Temperature on Microstructure and Mechanical

• Abstract: The quenching and nonisothermal partitioning process has been found to achieve excellent combinations of strength and ductility through the retention of austenite in the microstructure. Therefore, in the present study, the effect of grain size on phase transformations and ensuing mechanical properties has been investigated. A low-Si and Al-free steel was finish rolled at different temperatures which was subsequently quenched to a constant temperature below Ms for the formation of martensite with remaining untransformed austenite. This was followed by slow cooling to room temperature to simulate the condition of nonisothermal partitioning of carbon from martensite to the austenite. The results show that there is not much change in the average grain size with variation in the finish rolling temperature, as well as, no measurable differences are observed in the microstructural features and retained austenite content. The microstructure shows the presence of martensite, carbides, and a small amount of retained austenite. However, in terms of mechanical properties, the finish rolling at a lower temperature of 900 °C lead to higher hardness and strength with comparable ductility in comparison to the sample which has been finish rolled at a relatively higher temperature (940 °C). The above results will thus be helpful in designing the industrial processing schedule for low-Si steel to achieve enhanced performance.
PubDate: 2021-04-21

• Energetic Behavior Study in Phase Transformations of High Temperature
Cu–Al–X (X: Mn, Te, Sn, Hf) Shape Memory Alloys
• Abstract: Shape memory alloys (SMAs) are increasingly used in a wide range of thermomechanical and thermoelectric applications that are of a macro-, micro- and nano-scale. Though the use of commercial Ni–Ti (NiTiNOL) SMAs is preferred in most of these applications, there is an ever-increasing demand for cost-effective and easy-to-produce alternatives to NiTiNOL. In terms of functional properties, copper-based SMAs are comparable to Ni–Ti SMAs. Moreover, Cu-based SMAs are cheaper and easier to produce and process. In order to improve the functional properties of binary Cu-based SMAs (Cu–Al, Cu–Zn and Cu–Sn), ternary elements are added in small quantities. This is also one of the most common methods that is used to improve the functional properties of NiTi- and Fe-based SMAs. In this work, Cu–Al-based alloys containing ternary elements, Mn, Sn, Te and Hf, were produced by arc melting technique. Thermal (DSC, DTA) and microstructural (XRD, metallography) analyses were then carried out on the alloys prepared so as to characterize them for their thermal and microstructural characteristics. The results demonstrate improved shape memory properties for these alloys. The transformation temperatures of the binary Cu–Al alloys determined showed higher values (Af > 100 °C). Among the ternary alloys, the highest transformation temperatures were found for alloys with Hf addition, followed by those with Te addition. But on the other hand, the most intense peaks corresponding to the martensitic transformation were observed for Sn addition. The microstructural investigations revealed the presence of martensite in the alloys which was consistent with the results of thermal analysis.
PubDate: 2021-04-21

• Using High Speed High Pressure Torsion for Cu–13Al–4Ni Shape Memory
Alloy Processing
• Abstract: Recently, severe plastic deformation (SPD) is recognized as a very efficient processing technique for the fabrication of bulk nanostructured (ns)/ultrafine-grained materials. High-speed high-pressure torsion (HSHPT) process, an SPD method, is used as a novel approach to produce ultrafine grains in memory materials. The influence of HSHPT process variables on some Cu-based shape memory alloys (SMAs) is explored and discussed. This paper also envisages providing a comparative study of significant microstructural evolutions and features that are introduced by HSHPT processing. The plastic deformation mechanisms of the copper-based SMAs are investigated from macrostructural and microstructural points of view using optical and scanning electron microscopic techniques. In addition, significant grain size reduction brought about by the process is attested by X-ray diffraction and transmission electron microscopy. The transition temperatures have been determined by differential scanning calorimetry.
PubDate: 2021-04-21

• Tuning Glass Formation and Mechanical Properties of ZrCoAl(Nb) Bulk
Metallic Glass with Nb Microalloying Process
• Abstract: In the present study, the effect of Nb addition on mechanical behavior and glass formation in (Zr56Co28Al16)100−xNb(x=0,2,4) bulk metallic glasses was studied. The differential scanning calorimetry (DSC) was used to investigate thermal properties of samples. Further, mechanical behavior of prepared samples was analyzed using quasi-static compressive tests. The results showed that 2 at.% minor addition of Nb enhances the glass forming ability (GFA), but larger amount of Nb (4%) deteriorates GFA. The X-ray diffraction patterns also confirmed that the structures of whole of studied compositions are amorphous. In addition, the compressive test results revealed that 2% addition of Nb significantly improves compressive ultimate strength (up to 2.5 GPa) and increases the plastic strain from 1.1% in the composition having no Nb content to ~ 6%. The observation of shear band branching and also the increase in the density of vein-like patterns in the fracture surface (studied by scanning electron microscopy) also confirm the improvement of plasticity in (Zr56Co28Al16)98Nb2 sample. Our finding highlights the effect of minor alloying on the formation and mechanical properties of bulk metallic glasses.
PubDate: 2021-04-21

• An Investigation on the Chemical Variation in TLP Joint Line and Its
Effect on High-temperature Corrosion Behavior of the Bonded IN738-Lc
• Abstract: Turbine blade face with crack generation during high-temperature application. Due to its high cost of manufacturing, repair of the damaged section is usually more desirable than its replacement. transient liquid phase (TLP) bonding is a common joining procedure used for maintenance of a gas turbine damaged vein and blade. This paper describes how the TLP joint area resist hot corrosion at high working temperatures. Microstructure and metal loss were studied from scanning electron microscope (SEM) images, and corrosion products were identified by XRD and EDS analyses. SEM observations revealed that the TLP area is composed of three distinguished regions: a thermally solidified zone with about 15 µm thickness, the isothermally solidified zone with about 32 µm thickness, and diffusion affected zone with about 54 µm thickness. Exposing test samples to Na2SO4/NaCl (3:1 wt%) salt mixture at 750 °C, creates a 40 µm of porous oxide scales containing the outer layer of chromium oxide and the inner layer of chromium–nickel oxides. Moreover, 160 µm of internal attacks were observed and were identified as sulfide attack. The corrosion attacks in the diffusion affected area were observed in the form of micro-cracks and internal sulfide island. The morphological together with cross-sectional studies on corroded samples showed that the thickness of corrosion product in TLP joint was more than that of area far from TLP centerline. Surfaces on the side of TLP line acted as the short-circuit path to deliver chromium and nickel to the corrosion exposure. Moreover, cracks which were formed during hot corrosion in TLP area, acted as short-circuit inward diffusion of sulfur, resulting in internal sulfidation. It is also suggested that the formation of boride and silicide intermetallics in the TLP area also weakens the corrosion resistance.
PubDate: 2021-04-19

• Hard Turning with a New HSN 2 -Coated Carbide Insert and Optimization of
Process Parameter
• Abstract: Turning of hard steel has several advantages like better surface finish, enhanced material properties, reduction in production cost, and increased production rate when compared to grinding. The present study deals with the hard turning of hard steel (AISI 4340) having a hardness value of 52 ± 1 HRC using a new HSN2 coating material on a carbide insert having a thickness of 12 µm. Further, it presents a study of various process parameters such as cutting speed, feed, and depth of cut on machining output like cutting forces, surface roughness, and tool wear. Also, a regression model by using central composite rotatable design of response surface method has been developed. The purpose of the regression model is to establish a correlation between the input and output parameters. To analyze the properties of the coating material such as oxidation and thermal stability at high temperature, both thermogravimetric analysis and differential scanning calorimetry characterizations are performed. Further, an optimization study of the cutting parameters has been carried out, and the results are validated with confirmation tests having an error within the acceptable range. The maximum measured flank wear is 159 µm which is lesser than 400 µm as per ISO Standard 3685.
PubDate: 2021-04-18

• Crystallization Characteristics of the CaO–SiO 2 –Al 2 O 3 –La 2 O 3
Rare Earth-Bearing Slag System
• Abstract: The crystallization behaviors of CaO–SiO2–Al2O3–La2O3 slags with different basicities and P2O5 and CaF2 additions were investigated. The results showed that the rare earth (RE)-rich crystallization phase was transformed from CaLa4(SiO4)3O to CaLa4[(Six,P1−x)O4]3OF3(1−x) with P2O5 and CaF2 additions due to the substitution of Si4+ and O2− ions by P5+ and F− ions, respectively. The basicity increase promoted the crystallization of the RE-rich phase and Ca2Al2SiO7 phase of the slags and dominated the formation of the Ca2Al2SiO7 phase. Although the addition of P2O5 increased the area fraction of the RE-rich crystallization phase in slags, it decreased the La content of the RE-rich phase. CaF2 addition also decreased the La content of the RE-rich crystallization phase, but the reduction effect was weaker than that of P2O5. Furthermore, CaF2 had little effect on the area fraction of the RE-rich crystallization phase in the current slags.
PubDate: 2021-04-18

• Tribological Analysis of Engineering Plastics/Steel Friction Pairs
• Abstract: This study involves the case of polymer–metal contact, where deformation and strain behavior play a significant role. In present work, a section of polymer gear is mated against steel gear, and the friction behaviors for different groups of polymer materials of PA 6G, PA 6G Mg, POM-C, PETP/PTFE, PA 66 GF 30 and Bakelite were experimentally studied. From the results obtained, all the materials coefficient of friction decreased significantly at the pitch point. This was attributed to the pure rolling at the pitch point and tangential traction, which was the dominant mechanism for resistance to motion. An unstable friction characteristic from flank tooth to the pitch point was evident in the low load conditions.
PubDate: 2021-04-17

• Effects of Cu on the Morphology and Growth Mode of Graphite in Compacted
Graphite Iron
• Abstract: In this article, Cu is found to have a great influence on the graphite morphology and growth mode in compacted graphite iron (CGI). Metallographic pictures show that the number of vermicular graphite of the surface of CGI casting is significantly higher than that of the core, and there is more spheroidal graphite in the core of casting. In addition, a special form of graphite, which is defined as distorted graphite appears in the matrix. From the EPMA results, it can be concluded that the segregation of Cu promotes the distortion of graphite, and part of distorted graphite is transformed into vermicular graphite under the action of vermicular elements (Mg, La, and Ce). The increase in the number of spheroidal graphite improves the strength of casting, but it reduces the thermal conductivity.
PubDate: 2021-04-15

• Improving the Tensile Shear Load of Al–Mg–Si Alloy FSLW Joint
by BPNN–GA
• Abstract: In order to obtain the joint with a high tensile shear load, the small penetration of tool pin into the lower sheet was applied during friction stir lap welding. The tensile shear loads of the Al–Mg–Si aluminum alloy joint under different process parameter combinations were optimized by combining back propagation neural network and genetic algorithm. The result showed that the hook bent down and the height of cold lap was small. Under the external tension load, the crack propagated along the lap interface or extended downward after reaching the highest point along the cold lap. With the increase of heat input, the tensile fracture mode of joint was more easily obtained. The highest tensile shear load of the joint reached 12.45kN, which was increased by 6.9% than the maximum value before optimization.
PubDate: 2021-04-13

• Microstructure and Mechanical Properties of the AA7075T7352 Aluminum Alloy
• Abstract: Microstructure evolution and their effects on mechanical behaviors of the AA7075T7352 aluminum alloy are reported. Phase analysis was done by X-ray diffraction and transmission electron microscope. The presence of the GP-Zones, ɳ', and ɳ, along with Al2Cu, Al2CuMg, and Al3Zr, was noticed. Mechanical characterizations were done with the help of a tensile test and Vickers microhardness. Flow behaviors were studied to evaluate the impact of second-phase particles in the properties. Strain hardening exponents along with UTS/YS ratio have been calculated. Flow curve fitting follows Ludwigson relationship with two distinct slopes. Dislocation loops and forest dislocation were noticed in the low strain range, while dense dislocation walls in the high strain range. Variation in flow parameters is due to the random spread of precipitate particles in the matrix. The material fails by mixed mode of ductile and brittle fractures.
PubDate: 2021-04-12

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