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Wood can be processed into structural materials by partial removal of lignin and subsequent hot compression. The fundamental challenge of this process is achieving a cost-effective, green, and scal...

Coatings have been used for a significant number of years in the Direct Reduction industry, and the ISO Cluster Index plays an important role in this context since it allows a better predictability of pellet performance in the industrial process. The present work developed a series of tests and characterization in order to better understand which materials, methods, and characteristics would be most relevant to decrease the clustering index. It was noticed that coating on green pellets is worse as compared to the conventional application method which coats the pellets after the hardening process in the pelletizing furnace. In an evaluation of predictive parameters, it was observed that the adhesion index and the sum of SiO2, Al2O3, CaO, and MgO content influence the clustering index response variable. Consequently, it was observed that the adhesion index is proportional to the microporosity and mesoporosity of the coating materials. Bauxite was the material that showed the best performance. Its differentials were the high content of Al2O3 combined with its high microporosity/mesoporosity, i.e., pores with diameter up to 50 nm.

In the present study, the effect of the double quenching–tempering heat treatment on the mechanical properties of the HSLA-100 steel has been investigated. In this regard, the steel studied was first subjected to two consecutive austenitization treatments at 940°C and 870°C for 45 and 30 minutes, respectively, and quenching, followed by tempering in the temperature range of 510°C to 700°C for 60 min, and finally all the samples were cooled in air. Also, to compare the results with the conventional heat treatment cycle of this steel, some samples were subjected to single quenching–tempering. Furthermore, the variations of mechanical properties of HSLA-100 steel and the resultant microstructures were investigated in terms of different tempering conditions. Accordingly, it was found that the double quenching–tempering treatment could create a substantial difference in the total elongation percentage (+24%) of the samples by making minor changes in the strength parameters.

Aircraft structural materials corrosion will not only affect flight safety and need great maintenance work, but also cost much money and shorten the service period. A durable aircraft structural corrosion inhibiting compounds (CIC) coating was prepared by introducing dodecyl modified graphene oxide (GO-DDA). The lightweight GO-DDA lamellar can be uniformly dispersed in the CIC-35 matrix, which has consequently led to satisfying corrosion resistance (E: 0.072V, I: 1.18×10-7 A/cm2, and Rp: 6.87×106 Ω·cm2). At a filler content of 2.0 wt.%, the composite coating could maintain a high PE value even after a 30-day of accelerated UV-condensation aging. Given the facility in preparation as well as the superior corrosion resistance, this work will shed light on the further fabrication of composites coatings toward lightweight, high anti-corrosion performance and long-term effectiveness to meet the high requirement in practical applications such as aviation and shipping fields.

New results about the influence of a small iron borided layer (~ 36 µm) obtained by the powder-pack boriding process (PPBP) and diffusion annealing post-process (DAP) were evaluated. Dry sliding wear tests on PPBP, PPBP + DAP and untreated AISI 1018 steel were performed under the pin-on-disc configuration, and balls of Al2O3 and WC were used as a counterpart at different sliding distances. Also, the contact pressures of the layer/substrate system were evaluated using the finite element model with the aid of the ABAQUS software. The results showed that the Al2O3 ball presented the major coupling (ball-disc), and the PPBP + DAP reduces the specific wear rate around ~ 304 times related to the untreated AISI 1018 steel to 500 m under severe sliding conditions.

A key-factor for the industrial implementation of beam-based additive manufacturing technologies is the development of novel Al alloys characterized by enhanced hot-tearing resistance. Indeed, most of the standard Al alloys are susceptible to solidification cracking and can hardly be used to produce structural parts by laser-based additive manufacturing processes. In this study, we investigate the strategies to design high-strength Al alloys for Laser Powder Bed Fusion. The addition of Zr to the chemical composition of an Al–Mg–Si alloy (EN AW 6182) was carried out by following two different routes to promote the formation of equiaxed grains which are able to suppress hot cracking and enhance processability of the material. The first route is based on mechanical mixing of ZrH2 particles and gas-atomized Al alloy powder and on the in-situ reaction of the hydride to form Al3Zr nucleants. The second route relies on the use of pre-alloyed gas-atomized powders that feature Zr among the alloy elements. The specimens produced using pre-alloyed powder showed the best mechanical performance. After direct aging from the as-built condition, the alloy showed yield strength and ultimate tensile strength of 354 and 363 MPa, respectively, and elongation at fracture of 9.0 pct. The achieved properties are comparable to those of wrought 6182 alloy processed by conventional routes.

This paper demonstrates how an analytical and experimental method can be used to rapidly define the additive manufacturing settings for a new alloy where the process parameters were previously unknown. A nickel-based superalloy, Haynes 282, was chosen for the analysis. An experimental matrix of focused processing parameters was predicted with a dimensionless number and 100 samples were printed using the Laser Powder Bed Fusion technique. High-throughput measurements validated the predicted process conditions needed to achieve desired density and hardness. The whole process was completed in 16 hours. The new technique was confirmed with analytical processing maps adopted by the metal additive manufacturing community. With the predicted set of process parameters, a low-throughput analyses of conventional microstructural characterizations and tensile testing were used to test the predictions. The resultant as-fabricated microstructures have refined length scales of both microsegregation and secondary phase distributions. The mechanical properties were comparable within the predicted processing window and exhibited high strength and high ductility.

The present study was performed on 356 and 413 alloys solidified at 8 °C/s. The samples from 413 alloys were solutionized at 510 °C, whereas samples from 356 alloy were solution heat treated at 555 °C, for times up to 1200 h. All polished samples were deeply etched using Keller’s etchant to dissolve the aluminum matrix and expose the eutectic silicon particles. Etched samples were investigated using field emission scanning electron microscopy (FESEM). It was observed that Sr-modified 356 alloy can nearly reach complete spheroidization in that all eutectic Si particles will be individually distributed throughout the matrix after a solutionizing time of 1200 h. Non-modified 356 alloy, under the same condition, still revealed partial fragmentation similar to Sr-modified 413 alloy. There was no complete spheroidization in non-modified alloys which explains the reported large standard deviation when polished samples are examined using optical microscopy. In other words, observations made from deeply etched samples (3D) disagree with those obtained from polished samples (2D). In addition, it is impossible to achieve coarsening of the spheroidized Si particles under industrial conditions. The present study was supported by statistical analysis as well as tensile testing.

The present study is the first attempt to join ultrafine-grained materials by electron beam welding. The aim of the study was to check the feasibility and effectiveness of this type of welding for thermally unstable materials. The results obtained are of high interest, while the welding did cause a decline in mechanical properties, the results were comparable to those obtained using solid-state welding, but with a significant advantage of narrower fusion- and heat-affected zones.

This work studies the solidification processes and microstructures of Zr55Cu30Al10Ni5 (at. pct) and Cu64Zr36 (at. pct) amorphous alloy sheets fabricated by twin-roll strip casting. A largely excessive volume was frozen in the alloy during the twin-roll strip-casting process, resulting in many soft regions and the inhomogeneity of the microstructure in the amorphous alloy sheet. The results provide insights into the solidification process of amorphous alloys and guidelines for adjusting their microstructure.

In this paper, a modulated permanent helical magnetic field is imposed to improve segregation during directional solidification in a binary Sn–3.5 wt pct Pb alloy. The magnetic force created by this magnetic field significantly interferes with heat, mass and momentum transfer of molten metal during solidification. Our experimental results show that this magnetic field, with an appropriate modulation frequency, can not only promote columnar-to-equiaxed transition (CET) but also significantly reduce solute segregation otherwise caused by conventional helical magnetic fields. Our analysis demonstrates the advantages of this approach over natural convection and conventional electromagnetically forced convection.

Environment-assisted fracture (EAF) behavior of Inconel718 (IN718) specimens made from virgin and recycled powder by laser powder bed fusion (L-PBF) process was investigated. To this, in situ slow strain rate tests (SSRTs) and fatigue crack propagation (FCP) tests were conducted in air and 3.5 pct NaCl/60 °C/Ecorr + 0.1 VSCE. Powder recycling up to 6 times did not affect the EAF sensitivity of L-PBF IN718 specimens in chloride-bearing environment, despite the marginal decrease in electrochemical resistance. Detailed fractographic and micrographic analyses were performed to identify the effect of powder recycling on static and dynamic EAF behaviors of L-PBF IN718 specimens.

Bulk metallic glass has been a fascinating class of metallic systems with remarkable corrosion resistance, elastic modulus, and wear resistance, while evaluating the glass forming ability has been a very interesting aspect for decades. Machine learning techniques, viz., artificial neural networks and KNearest Regressor-based models have been developed in this work to predict the glass forming ability, given the composition of the bulk metallic glassy alloy. A new criterion of classification of atoms present in a bulk metallic glass is proposed. Feature importance analysis confirmed that the accuracy of the prediction depends mainly on change in enthalpy of mixing and change in entropy of mixing. However, among the artificial neural network models and KNearest Regressor models developed, the former showed a promising performance in prediction of the glass formation ability (critical thickness). It has been successfully demonstrated and validated with experimental critical thickness that the glass forming ability can be predicted using an artificial neural network given the elemental composition alone. A computational algorithm was also developed to classify the atoms as big/small in each given alloy. The outcome of this algorithm is used as input parameters to the ANN and other machine learning models used in this work.

Understanding diffusion-induced isothermal solidification time during transient liquid phase bonding is vital in producing intermetallic-free robust joints. The isothermal solidification completion time is overestimated by the existing analytical models, even by the closest one to the real bonding conditions, known as the moving interface model. It was found that the boride formation in the diffusion affected zone of Ni-based superalloy upon using B-containing filler metals is one of the reasons behind the inability of the moving interface model to predict the isothermal solidification completion time accurately, which has received scant attention in the literature. Moreover, simplified assumptions in deriving the moving interface model such as constant interfacial solute concentration, which is only valid for binary systems, along with the independency of diffusion coefficient to concentration introduce errors when estimating the isothermal solidification time using the moving interface model. The significant discrepancy between the predicted and experimentally obtained isothermal solidification times reinforces the idea that the existing moving interface analytical model needs to be modified.

Environmental barrier coating (EBC) materials that are resistant against molten calcia-magnesia-aluminosilicate (CMAS) corrosion are urgently required. Herein, multicomponent rare-earth (RE) disilicate ((Yb0.2Y0.2Lu0.2Sc0.2Gd0.2)2Si2O7, (5RE)2Si2O7) was investigated with regard to its CMAS interaction behavior at 1400 °C. Compared with the individual RE disilicates, the (5RE)2Si2O7 material exhibited improved resistance against CMAS attack. The dominant process involved in the interaction of (5RE)2Si2O7 with CMAS was reaction-recrystallization. A dense and continuous reaction layer protected the substrate from rapid corrosion at high temperatures. The results demonstrated that multicomponent strategy of RE species in disilicate can provide a new perspective in the development of promising EBC materials with improved corrosion resistance.

Many studies have focused on the effect of fusion plasma particles onto the structural materials of future nuclear fusion reactors. In this paper, the effect of the products of the first-generation fuel reaction on structural fusion materials, such as copper and 316-stainless steel target materials, was studied. Firstly, the effect of 14.1 MeV neutrons produced from D–T neutron generator for different irradiation times, 10, 20, 30, 50, and 60 min, was investigated. Hence, this effect was analyzed and characterized by X-ray diffraction analysis, surface roughness test, scanning electron microscope, and Vickers hardness. Secondly, the effect of 3.5 MeV α-particles on these target materials by different incident angles, 0°, 30°, 45°, 60° and 85°, using SRIM code was studied. Also, SRIM code was used to calculate α-particles’ trajectories, projected and straggle ranges, skewness, kurtosis, target ionization/phonons, and total displacements for copper and 316-stainless steel target materials.

The present study has investigated the influence of sulfur content in synthetic FeMn and SiMn from 0 to 1.00 wt pct on interfacial properties between these ferroalloys and slags. The effect of experimental parameters such as temperature and holding time was evaluated. Interfacial interaction between ferroalloys and slags was characterized by interfacial tension and apparent contact angle between metal and slag, measured based on the Young–Laplace equation and an inverse modelling approach developed in OpenFOAM. The results show that sulfur has a significant influence on both interfacial tension and apparent contact angle, decreasing both values and promoting the formation of a metal-slag mixture. Despite the fact that sulfur was added only to the ferroalloys, most of sulfur is distributed into slag after reactions with the metal phase. Increasing the maximum experimental temperature in the sessile drop furnace also resulted in a decrease of both interfacial properties, resulting in higher mass transfer rates and intensive reactions between metal and slag. The effect of holding time demonstrated that after reaching equilibrium in FeMn-slag and SiMn-slag systems (both with and without sulfur), interfacial tension and apparent contact angle remain constant.

Architectured lightweight steel composites were designed and fabricated through the cold roll bonding (CRB) of stacked steel-aluminum sheet layers. The effects of geometrical parameters including thickness ratio (TR) and the number of constituent layers on bond strength and tensile properties of the composites were evaluated using peeling and tensile tests. It was found that by decreasing the TR of aluminum to steel from 0.5 to 0.2, the bond strength increased in the as-rolled specimen. However, it led to a decrease in the bond strength of the annealed sample by the facilitation of the formation of Fe–Al intermetallics along the interfaces. In order to obtain a more in-depth understanding of deformation behavior at the interface of steel/aluminum layers, strain gradient at these regions was evaluated through the measurement of dislocation density using the XRD analysis. Macrotexture measurement and anisotropy analysis were also carried out to evaluate the formability of the optimized sample. Moreover, it was found that by increasing the number of layers, the bond strength decreased due to the insufficient extrusion of the virgin metals to the interface of the layers. Higher steel/aluminum interfaces as effective microstructural heterogeneities improved the elongation in five-layered and seven-layered composites by arresting the propagating cracks. Employing the concept of laminated composite led to the production of a lightweight architectured steel with density of 5.6 g.cm−3, which can be a promising structural material for automotive applications.

High performance colloid flake of carbon is gaining interest due importance in meeting the challenges of the globe. To make novel superior materials, the pulverized fuel ash-green adhesive based construction materials modified with the flake of carbon and the colloid flake of carbon were evaluated in view of synthesis, physico-mechanical properties, and material processing and models. For better understanding, such experimental samples as green adhesive plaster and green adhesive grout were made of the pulverized fuel ash of class C, the common adhesive, the flake of carbon, the colloid flake of carbon, fine sand, and the distilled water to compare with the structural material properties each other. The results of the adsorption spectra of optical atomic spectroscopy of the colloid flake carbon, the thickening-period of plaster, the spread and the consolidating level, the apparent unit volume mass, the apparent porosity, the apparent compacity, and the compressive stress of green grouts were reported in the research. It was concluded that the flake of carbon and the colloid flake of carbon led to important progress in the novel superior materials, e.g., accelerating of the thickening-period of plasters and increasing of the compressive stress of grouts. (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Engineered cementitious composites (ECC) show the distinguished characteristics of high post-cracking resistance and ductility. High-strength stainless steel wire rope (HSSSWR) has been successfully used for restoring or strengthening of existing structures. By combining the advantages of these two materials, a new composite system formed by embedding HSSSWR into ECC was proposed and expected to be a promising engineering material for repair or strengthening of structures. To investigate the tensile failure mechanism and mechanical properties of HSSSWR-reinforced ECC, an experimental study on 27 HSSSWR-reinforced ECC plates was conducted considering the effects of the reinforcement ratio of longitudinal HSSSWRs, formula of ECC and width of the plate. Test results revealed that HSSSWR-reinforced ECC exhibit superior post-cracking resistance, deformation capacity and crack-width control capacity. Increasing the reinforcement ratio of longitudinal HSSSWRs can effectively enhance the tensile strength, crack-width control capacity, deformation capacity and tensile toughness of HSSSWR-reinforced ECC. Adding thickener in ECC can significantly improve the crack-width control capacity and deformation capacity of HSSSWR-reinforced ECC due to enhancing uniform distribution of polyvinyl alcohol fibers, but would slightly reduce the cracking stress and maximum tensile stress by bringing small bubbles in the matrix. The tensile properties of HSSSWR-reinforced ECC plates are almost not affected by varying the plate width. Besides, a tensile constitutive model was developed for charactering the stress–strain relationship of HSSSWR-reinforced ECC in tension. Based on mechanical theories and failure characteristics of HSSSWR-reinforced ECC, the model parameters were determined, and calculation equations of cracking stress and tensile strength were proposed. The accuracy of the developed model and calculation equations was verified by test results.

Low-carbon steel is a common structural material, but additively manufactured structural component of this material is rare due to its inhomogeneous properties. In this article, the wire arc additive manufacturing method was used to achieve near homogeneous properties of a low-carbon steel structural component. The process heat input was optimised for the desired layer geometry, and then the optimal energy was applied with a time delay to deposit individual layers. The time delay was used to achieve cyclic heating and cooling treatment of deposited layers. The best possible robotic tool path movement with multi point arcing was further adopted in the study to achieve proper thermal distribution across the structural component. The microstructure of layers was dominated by quasi-polygonal ferrite morphology and pearlite precipitation, with little variation in quantity across the component. The hardness profile was almost consistent with the average hardness of ∼176.92 HV. The proof stress slightly increases with decrease in grain size and increase in ferrite/pearlite ratio, however, the overall tensile behaviour is homogeneous with average σ0.2, σu and ε% values of 427.78 MPa, 527.89 MPa and 22.31%, respectively. The quasi-ductile fracture was generally occurred due to void coalescence around larger inclusions. The overall analysis showed that more than 90% of homogeneity was achieved in microstructural and mechanical behaviour of the deposited component.

The activation energy of creep rupture is determined based on a new tensile creep rupture model and then applied to rationalize the creep rupture data measured over a wide range of stresses and temperatures, which enabled the predictions of 100,000 hours and 200,000 hours creep rupture strengths to be made at different temperatures in the range of 650 °C to 875 °C for alloy Inconel 740/740H. The reliability of such long-term predictions is also analyzed.

Synergetic strengthening by designing of gradient nanostructures is a novel method to enhance strength in metals and alloys. Herein, we realize synergetic strengthening in strain-softening Zn alloy with gradient nanostructures. The results show that synergetic strengthening accounts for at least 25.5 pct of the yield strength of the strain-softening Zn alloy. The synergetic strengthening is induced by the microstructural gradient and the resultant strength gradient regardless of specific hardening or softening of the refined microstructures.

Layer-structured interphase, existing between reinforcing fiber and ceramics matrix, is an indispensable constituent for fiber-reinforced ceramic composites due to its determinant role in the mechanical behavior of the composites. However, the interphase may suffer high residual stress because of the mismatch of thermal expansion coefficients in the constituents, and this can exert significant influence on the mechanical behavior of the composites. Here, the residual stress in the boron nitride (BN) interphase of continuous SiC fiber-reinforced SiC composites was measured using a micro-Raman spectrometer. The effects of the residual stress on the mechanical behavior of the composites were investigated by correlating the residual stress with the mechanical properties of the composites. The results indicate that the residual stress increases from 26.5 to 82.6 MPa in tension as the fabrication temperature of the composites rises from 1500 to 1650 °C. Moreover, the increasing tensile residual stress leads to significant variation of tensile strain, tensile strength, and fiber/matrix debonding mode of the composites. The sublayer slipping of the interphase caused by the residual stress should be responsible for the transformation of the mechanical behavior. This work can offer important guidance for residual stress adjustment in fiber-reinforced ceramic composites.

Aluminum alloys are widely used in the production of aerospace, aircraft, and automotive components. The die casting components are subjected to post-processing operations, such as milling and turning operations to get final shape, surface finish, and dimensional tolerances. During machining operations large quantities of material are removed from the cast components in the form of chips to achieve final shape and size. The chips that are produced during machining operations are mixed with oils, lubricants. This article discusses how effectively the aluminum can be recovered from the chips with maximum metal recovery and minimum melting loss without compromising quality and chemical composition. The different types of techniques are employed, and their results are discussed in this paper. Al-Si8Cu3Fe (LM24) alloy is selected for investigation purposes. The recovery techniques, such as with flux, without flux, with different melting furnaces, with different melting temperatures, with or without compacting, are studied.

Fluorspar (CaF2) is commonly used to control the fluidity of slag in ladle-refining of steel. However, because it is desirable to reduce CaF2 consumption because of its environmental impacts, the industrial waste material such as white mud (WM) was investigated as a potential substitute for fluorspar. Steel sample (Fe-0.3C-0.9Mn-0.3Si-0.03Al-0.05S, mass pct) was melted in a high-frequency induction furnace, followed by additions of ladle slag (CaO-Al2O3-SiO2-5MgO-xCaF2, CaO/Al2O3=3, x = 0 to 10 mass pct) and fluxing agent (WM) at 1823 K (1550 °C). The desulfurization experiments were carried out by reducing CaF2 content in the ladle slag and increasing the addition of WM. Ladle slag with added WM showed an overall mass transfer coefficient of sulfur (k O) equivalent to or higher than that of conventional 10 mass pct CaF2-containing ladle slag. In a slag melting experiment based on DIN 51730 standard, the melting rate of mixed slag increased with the amount of WM added, which is considered to have a positive effect on the initial desulfurization rate. In addition, adding WM provided sulfide capacity of the slag equivalent to that of CaF2-containing slag. Consequently, the use of WM yielded slag having $$k_{{\text{O}}}$$ k O equivalent to or higher than that of conventional ladle slag with 10 pct CaF2, and thus, WM shows promise as a partial replacement for fluorspar.

Permeable asphalt mixtures are widely used to achieve good permeability of the pavements used for urban road surfaces. Based on the law of water migration in permeable road structures, the water-holding performance of permeable asphalt mixtures was analyzed and the evaluation indexes were determined. Open-graded asphalt friction course (OGFC-13) permeable asphalt mixture was selected, and the changes in the saturation, water retention, and water-holding rate of OGFC-13 permeable asphalt mixtures with different porosities were compared using water-holding equipment. The water-holding characteristics of permeable pavement materials under different seepage conditions were analyzed. A model of the relationship governing the water-holding capacity of the permeable asphalt mixture, water action conditions, and material porosity was established by a linear fitting method, and the reliability of the model was verified by comparison with laboratory test results, providing a foundation for related research on the water-holding and cooling behavior of permeable pavements.

This paper addresses the use of alloying additions to titanium alloys for additive manufacturing (AM) with the specific objective of producing equiaxed microstructures. The additions are among those that increase freezing ranges such that significant solutal undercooling results when combined with the rapid cooling rates associated with AM, and so be effective in inducing a columnar-to-equiaxed transition (CET). Firstly, computational thermodynamics has been used to provide a simple graphical means of predicting these additions; this method has been used to explore additions of Ni and Fe to the alloy Ti–6Al–4V (Ti64). Secondly, an experimental means of determining the minimum concentration of these alloying elements required to effect the CET has been developed involving gradient builds. Thirdly, it has been found that additions of Fe to Ti64 cause the alloy to change from an α/β Ti alloy to being a metastable β-Ti alloy, whereas additions of Ni do not produce the same result. This change in type of Ti alloy results in a marked difference in the development of microstructures of these compositionally modified alloys using heat treatments. Finally, hardness measurements have been used to provide a preliminary assessment of the mechanical response of these modified alloys.

An ultra-low carbon bainitic steel is developed through nanoprecipitation of high-density Mn/Fe-rich intermetallic B2-NiAl. A high yield strength of ~ 1.3 GPa and a good total elongation of ~ 13 pct are attained via minimal lattice misfit nanoprecipitation. Atom probe tomography and high-resolution transmission electron microscope were applied to characterize nanoscale precipitates. An increment of 544 MPa in yield strength is achieved after an aging process, predominantly attributed to the order strengthening mechanism.

This work is motivated by the industrial process of air (or dry) atomization of slag, where a high-speed jet of air impinges onto a free-falling stream of molten slag and disintegrates it into small droplets. The droplets solidify to form slag powder particles which may be used in applications such as sand blasting, roof shingles, and asphalt. Since different applications require slag powders with different ranges of particle size, controlling the particle size is of essence. A mathematical model is presented for the atomization process, which relates the Sauter Mean Diameter (SMD or $${D}_{32}$$ ) of molten slag droplets to the atomizer design and operating parameters. The model solves a set of non-linear governing equations, including conservation of mass, momentum, and energy, in the integral form using an iterative method. This universal model can be applied to any combination of gas-liquid, and thus the model is validated with existing experimental results for air atomization of a water stream. A strong agreement exists between the calculated and experimentally measured values of $${D}_{32}$$ . It is also found that at a constant air flowrate, the liquid flowrate affects the $${D}_{32}$$ of droplets and the opening angle of the spray; the former is the main output parameter, and the latter is an intermediate parameter.

To verify the performance of self-developed high viscosity modified (HVM) asphalt binder with styrene–butadiene–styrene (SBS) composite modifier, the various branched and linear SBS modifiers with different mixing ratios were selected to prepare HVM asphalt binder, and the mix proportion of SBS modifier in HVM asphalt binder was also optimized. The fluorescence microscope, multiple stress creep recovery (MSCR) test, bending beam rheometer (BBR) test, improved boiling water test and viscosity test were used in this study, and the different properties of HVM asphalt binder with SBS composite modifier, HVM asphalt binder with linear SBS modifier, HVM asphalt binder with Tafpack-super (TPS) modifier (TPS-HVM asphalt binder) and HVM asphalt binder with SINOTPS modifier (SINOTPS-HVM asphalt binder) were evaluated. The results show that the mixing ratio of linear SBS modifier and branched SBS modifier in the composite modifier is 2:1, the dispersible uniformity and road performance of HVM asphalt binder with the composite modifier are better, and the modification of composite modifier with SBS-1301 and SBS-4303 modifier is greater than LG-501 and LG-411, LCY-3501 and LCY-3411. The performance of HVM asphalt binder with the composite modifier was significantly influenced by the mix proportion and structure of SBS modifier. The dispersion effect of SBS modifier is superior to TPS and SINOTPS additive. The high-temperature performance, adhesion and viscosity of HVM asphalt binder can be increased by addition of SBS composite modifier, but the low-temperature performance of HVM asphalt binder is decreased slightly. The flexibility of HVM asphalt binder with linear SBS modifier at low temperature is better than SBS composite modifier. Compared to TPS-HVM and SINOTPS-HVM asphalt binder, the low-temperature performance and adhesion of HVM asphalt binder with SBS composite modifier are relatively good, while the viscosity of HVM asphalt binder with SBS composite modifier under high temperature is lower. The elasticity of different HVM asphalt binders decreases in order SINOTPS-HVM asphalt binder, HVM asphalt binder with SBS composite modifier and TPS-HVM asphalt binder. This study will be provided more options for the asphalt binder of porous asphalt pavement and steel deck pavement.

This work concurrently investigates the microstructure evolution and stress state during continuous cooling of 1045 steel gear parts. A finite element algorithm was developed by two-way coupling of microstructural and thermal fields. Thermal coefficients were correlated to microstructural evolution, and a phase transformation kinetics model was considered to be both temperature and time dependent. Magee's rule was chosen for martensitic transformation modeling to incorporate the effect of stress state on microstructural field. The dilation curves for the benchmark sample show that martensite starting temperature increases when the stress state is considered in microstructure modeling. To determine the validity of the presented model, a cylindrical specimen was quenched in water and oil media, and their predicted microstructures were compared with experimental results. A reasonable harmony between simulated and experimental results was observed. The simulation was then performed for internal gear parts quenched in oil and water media. The simultaneous monitoring of microstructure and stress evolution during continuous cooling of an internal gear part was conducted. It was shown that simultaneous and separate transformations occurring between the tooth and root region have a determining role in the sign of stress for internal gear parts. Lastly, based on monitoring of different phase transformation scenarios occurring during water and oil quenching, a hybrid quenching was proposed to increase martensite volume fraction at the tooth region of an oil-quenched sample without altering the microstructure at root region.

This study investigates the effect of different solidification cooling rates (0.5, 7.5, 13.5, 57.5, and 85 °C/s) on the solidification parameters, microstructure evolution, and mechanical properties of AA5056 Al-Mg alloy. According to the results, augmenting the cooling rate lowered the solidification time, and due to high thermal undercooling, substantially refined the microstructure. For instance, increasing the cooling rate from about 0.5 to about 85 °C/s decreased the fraction of Al3Mg2, Mg2Si, and Fe-rich compounds by 58, 64, and 27%, respectively. It also substantially refined the grains, reduced the size of secondary dendrite arm spacing (SDAS), and lowered the porosity content from about 3.8% to about 0.3%. The hardness, tensile strength, and fracture strain of the alloy increased by 44%, 140%, and 395%, respectively, as the cooling rate increased from 0.5 to 85 °C/s. The fracture mechanism also changed from a brittle-dominated mode to a high-energy ductile mode comprising of extensive dimpled zones at the higher cooling rates.

To solve the problem of application of the reduction process in the continuous casting of round blooms, double-roll, three-roll and four-roll staggered extrusion schemes were proposed, and three series of three-dimensional thermal-mechanical coupling models were established to analyze the advantages and disadvantages of each reduction scheme. It was found that the double-roll scheme transfers the reduction deformation to the center of the round bloom and closes the internal porosity more efficiently. For each squeeze, the double-roll extrusion scheme can easily cause lateral deformation, which may improve the equivalent strain value to the inside of the round bloom more efficiently, and there is a concentration phenomenon in the center after several sets of reductions. The three-roll scheme and the four-roll scheme have difficulty causing lateral extension, and the reduction is basically consumed by the harder shell deformation, which causes much more longitudinal stretching deformation of the round bloom. With an increase in the solid fraction (fs), the round bloom will accept a larger reduction under the limit of the initiation of internal cracks. At positions with the same fs, the tensile strain of the crack risk area caused by the double-roll scheme is larger than that of others, which means that the limitation of the maximum reduction amount of the double-roll scheme is stricter than that of the other two schemes.

The goal of this work is to accurately measure the viscosity of an industrial secondary copper smelting slag. Established literature commonly performed such measurements in non-inert labware, such as alumina. Despite the fact that the dissolution of alumina into the slag was addressed as a source for errors, a comprehensive analysis of how this interaction affects the measurement reliability is hitherto lacking. Furthermore, the type of dissolution (direct or indirect) will influence the interaction kinetics. This work aims to verify a possible relation between the dissolution and viscosity measurement reliability. For this purpose, the infiltration depth during and time stability of four different slag ( $${\text{{PbO}-{SiO}}}_{2}{\text {{-CaO}-{Al}}}_{2}{\text {{O}}_{3}}{\text {{-ZnO}-{Fe}}}_{2}{\text {O}}_{3}$$ ) viscosity measurements were analyzed. Both in-situ viscosity measurements and post mortem SEM images of the interface were therefore analyzed. It was observed that a multiphase interfacial layer was formed upon alumina dissolution. This layer consisted of a spinel intermediate layer and an enclosed interfacial slag. EDX measurements confirmed the difference between the latter layer’s composition and the bulk slag. Samples with a high interfacial slag viscosity yielded a dense spinel layer. As a result, alumina dissolved indirectly and more reliable viscosity measurements were obtained that were more stable over time. While samples with a low interfacial slag viscosity yielded a discontinuous spinel layer and therefore alumina could dissolve fast into the bulk slag, resulting in more unreliable viscosity measurements that varied over time.

In prior works, a novel method for continuously obtaining Al-Zr master alloys from oxide raw materials by electrolysis of a low-melting electrolyte based on the KF-NaF-AlF3-ZrO2 system at 800 °C to 820 °C was proposed. In the present work, the method for preparing the Al-Zr master alloy proceeded in an enlarged 100 A electrolyzer and the obtained master alloy was applied for grain refinement and improvement of its aluminum alloy properties. The modifying ability of the master alloy was studied, drawing on the example of the Al-Si-Fe alloy. Different amounts of the Al-Zr master alloy with a content of 10 wt pct zirconium were added to the Al-Si-Fe alloy at 900 °C. The effect of the zirconium content in the aluminum alloy and its cooling rate on its structure and properties was revealed. It was found that the addition of zirconium to the alloy refined the grain by 4 to 5 times without changing its shape or structure. A study of the joint effect of alloying and rate cooling indicated that a grain size reduction of up to 5 mkm can be achieved by these procedures.

Adjusting pitch ratio in green anode formulation is becoming difficult due to the increasing raw material variability. The optimal quantity of pitch yielding the best anode properties for a given aggregate, known as the optimal pitch demand (ODP), changes more frequently and is unknown a priori. Exceeding the OPD increases the risk of generating post-baking anode-sticking events. Previously, the potential of a principal component analysis (PCA)-based monitoring scheme for detecting the onset of these undesirable events was assessed by using a set of five green anode resistivity measurements collected from over 120,000 anodes produced over a two-year period. The squared prediction error (SPE) was shown to be sensitive to abnormal events such as anode sticking. The objective of this paper is to further validate the soft sensor by studying the SPE dynamic behavior during a post-baking sticking event when changes in the anode paste formulation were introduced as part of normal operation. Descriptive and statistical analyses demonstrate that the SPE metric reacts significantly to changes in the recipe. The provided example illustrates how the SPE metric used together with pitch ratio data could help advised the operators of manufacturing conditions posing a higher risk of generating post-baking sticking problems.

This paper describes an approach to furnace charge calculation for melting processes, to achieve a specified target melt in crucible or induction furnaces with minimum material cost. There has been a challenge with the problem regarding material loss, contaminations, and unwanted physiochemical reactions during the process. Those put a high degree of complexity, non-linearity, and uncertainty on the calculations. The current study presents a model that takes three important complexities of the problem into account, including non-homogeneous element loss during melting, non-metal contaminations in scraps/charges, and correction of possible initial melt in the furnace. The model was based on the mass balance of chemical elements along with the optimization of weights of charge materials. It presents a re-arrangement of non-linear mass balance formulations into an iterative standard linear-programming framework. To evaluate the performance of the model, an industrial-scale test case was introduced. The test problem was to find an optimum combination of charge materials to achieve target brass alloy C47940 in a 10-ton induction furnace. Eight different types of charge material were introduced to the model, with different amounts of non-metallic contaminations and different ratios of element loss in each. Also, 7-ton out-of-range initial melt was considered in the furnace to be corrected. The matrix of coefficients was build according to the numerical algorithm of the model. Optimizations were successfully performed in 3–5 iterations with Excel solver. For the test case, the calculations showed the optimum mass fractions of charge burdens and predicted to give 9649 kg melt with ~ 262 kg of total materials loss. An optimality analysis was conducted and showed that the solution has reached the minimum possible cost. The non-linear iterative algorithm revealed a convergent and fast performance. This feature provides a backbone for reliable and fast optimization in melting operations which is of significant benefit for industrial automation.

The wettability of liquid slag from the CaO-SiO2-MgO-Al2O3 system on a solid Al2O3 substrate at 1773 K has been investigated using the sessile drop experimental technique. The liquid slag compositions were chosen to represent blast furnace hearth slags and test the effects of changing the Al2O3 (5.2-18.9 pct) and V ratio (0.41-1.17) of the slag on its wettability on solid Al2O3. All slag compositions tested were wetting with respect to solid Al2O3, and the contact angle (θ) changed with time, rapidly decreasing in ~10–15 seconds from an initial value between 40 and 80 deg to a plateau value of ~18 to 19 deg at extended times. There was no obvious effect of changing the initial Al2O3 content of slag on the wetting behavior, but increasing the initial V ratio of the slag lowered θ. Similarly, there was no obvious effect of changing the initial Al2O3 content of the slag on spreading rate but the slags with the higher V ratio had a faster spreading rate. The apparent of adhesion (W) of the slags on the solid Al2O3 was also evaluated and found to increase for increasing Al2O3 content of the slag and increasing the V ratio of the slag. This higher W indicates a stronger bond between the slag and solid Al2O3 substrate. Using electro-optical techniques to characterize the slag-substrate interface, it was established that the slag had penetrated and reacted with the solid Al2O3 and formed a layer. As a result of this penetration/reaction, new phases formed. The specific phases that formed were dependent on the initial slag composition. In the changing initial Al2O3 slags at a relatively constant V ratio of 1.1 to 1.2, calcium aluminates, CA2 and CA6, were found. At the lower V ratios (0.41 and 0.60) but constant Al2O3, compositions consistent with spinel, feldspar and melilite were found.

Titanium suboxides with the general formula TinO2n−1 (n > 1.0), also referred to as Magneli phases, have been the subject of numerous studies due to their unique properties. Titanium low oxygen suboxides located at n = 1 (TiO) or below (Ti6O, Ti3O and Ti2O) are no less important; however, there is a lack of research on the synthesis of such materials. Therefore, in this article, the combustion process in a TiO2-KClO4-kAl-Flux exothermic system for 0.5 ≤ k ≤ 4.0 (k is moles of Al) is investigated experimentally and thermodynamically to synthesize TinO2n−1 ingots in the 0.5 to 1.0 range of n. The synthesis temperatures and equilibrium reaction phases are calculated with and without a KClO4 booster and several fluxes (CaF2, NaF, CaO and Na3AlF6), which are used to melt the reaction product and achieve the self-separation of the TinO2n−1 ingot from the Al2O3-containing slag. The formation TiO, Ti2O, Ti3O and Ti6O phases is confirmed via XRD analysis and the effectiveness of fluxes is highlighted.

Sodium cooled fast breeder reactors (SFR) are designed to operate at high-temperature conditions to achieve very high thermal efficiency (> 40%). Prototype Fast Breeder Reactor (PFBR) is a typical medium-sized SFR nearing the final stage of commissioning activities at Kalpakkam. High-temperature service conditions pose challenges in the structural design of PFBR components. Slenderness is the main characteristic of PFBR components. Thus, the PFBR design standard (RCC MRx) imposes tight manufacturing tolerances to achieve the required dimensional stability and improve the design life. Austenitic stainless steel (ASS) is the primary structural material used in manufacturing PFBR components poses challenges due to welding distortion. This paper discusses the engineering solutions adopted to qualify the manufacturing deviation of two selected prototype components without compromising the safety. They are, viz., (i) Main vessel-roof slab (MV-RS) in situ weld joint and (ii) Inclined Fuel Transfer Machine (IFTM) welded chain. A simulated creep experiment is conducted to demonstrate the required life of the selected MV-RS weld joint. Fatigue and break tests are performed to qualify the welded IFTM chain. These test results suggest that the imposed acceptance criteria were stringent, and those components met the safety requirements with sufficient margin.

Cement grouted asphalt mixture (CGAM) is developed with both flexible and rigid materials. It can be used to enhance the anti-rutting performance and increase the load bearing capacity of the pavement. However, the influences of cementitious grouting materials and asphalt binders on CGAM’s failure behavior have not been fully understood yet. In this study, the indirect tension (IDT) test, the compression test and the semi-circular bending (SCB) test were conducted to evaluate the strength and cracking resistances of CGAM with different cementitious grouting materials and asphalt binders. With different binders and bitumen/aggregate ratios, two kinds of cementitious grouting materials and six asphalt mixture skeletons were used in mixture design. IDT test results showed that the indirect tensile strength of CGAM would decrease as the bitumen/aggregate ratio increases. The addition of additives would also lower CGAM’s IDT strength. CGAM samples with high-strength cementitious grouting materials exhibited a higher strength than those with early strength cementitious grouting materials. However, there were not any distinct differences in the CGAM’s compression strength when different cementitious grouting materials and asphalt binders were used. SCB results showed that increasing the asphalt binder content and using additives can enhance the cracking resistance of CGAM. CGAM with high-strength cementitious grouting materials would crack more rapidly due to its rigidity. In the end, a two-way ANOVA was conducted on the results of the three tests. It is found that the type of grouting materials impacts the failure behavior of CGAM more significantly than the influences of the asphalt binder content. The addition of additives would also affect the failure of different CGAM samples. The findings in this paper can provide guidance for designing CGAM with better pavement performance.

The Cr–Mo ferritic steels are candidate structural materials for the pyrochemical reprocessing applications due to desirable high-temperature strength, resistance to oxidation, and etc. The corrosi...

Currently there is greater interest and an industrial need to create a bond between cast steel and aluminum alloys. The bond quality between these two metals must be considered, since it is affected by several casting techniques and parameters. This research aims to find the right combination of techniques and parameters to make a good bond between cast steel and aluminum alloys. This research systematically used the response surface methodology (RSM). Three important casting techniques and parameters are selected as independent variables, which are preheating temperature of cast steel, pouring temperature of aluminum alloy molten, and surface cleaning of cast steel. The gap between cast steel and aluminum alloy is used as dependent variable, which is defined as the quality measurement of the bond between two metals. The experiments were conducted on 48 samples, in which destructive test was performed in order to measure the gap. From the methodology, it is found that the recommended preheating temperature of cast steel is 491 °C, the recommended pouring temperature of aluminum alloy is 696 °C, and the recommended technique is cleaning the cast steel insert using degreasing. For practical purpose, the preheating temperature of cast steel can be set at 490 ± 10 °C and the pouring temperature of aluminum alloy can be set at 695 ± 10°C. This research limits on bimetal casting between cast steel and aluminum alloys, and the casting process is gravity die casting process. This paper is able to find the best casting techniques and parameters for cast steel and aluminum alloy bond using RSM. This paper also proposes gap bond between two metals as bond quality measurement.

Transverse cracking of concrete pavement in Ohio has been a major issue in interstate routes that reduces its service life to approximately ten to fifteen years, costing Ohio department of transportation great deal of maintenance funds. Major factors that aggravate slab failure are slab length, axle spacing and permanent built-in curl which are not directly incorporated in the AASHTO 1993 design procedure. The procedure implies an increasing thickness of concrete will be needed as traffic increases. However, fatigue testing of concrete beams has shown concrete can endure an unlimited number of loads if the stress ratio (SR) is kept below a critical value. Therefore, field and experimental data from Ohio concrete pavements were employed to validate a 3D finite element (FE) model with which critical slab stresses were calculated for several slab geometries. Results from stresses and fatigue damage analyses showed slab thickness of 12 in (305 mm) and slab length of 13 ft (3.9 m) were optimum for concrete pavement in Ohio. Long term pavement performance analysis showed the 12 in (305 mm) thick by 13 ft (3.9 m) long slab exhibited superior performance in terms of IRI, faulting, cracking, and cost over a 50-year design life.

The pavement is a structure, which is laid to support the wheel load and to spread the load stress to a wider area on the top of the soil subgrade. The process of changing the engineering properties of natural soil, to improve its strength, bearing capacity and other engineering properties by the addition of suitable stabilizer and admixture is collectively known as stabilization of soil. It is very much essential to improve the soil strength, bearing capacity and other engineering properties to sustain the loads acting on the pavement. By modifying the subgrade soil properties, the crust thickness of the pavement reduces. This paper focuses on the effect of TerraZyme stabilization on three types of major soils available in the coastal Karnataka region. The study deals with the improvement in the engineering properties of these soils after subjecting to TerraZyme chemical stabilization. Initially, tests were carried out to study the mechanical properties like compaction, permeability, unconfined compressive strength (UCS) and California Bearing Ratio (CBR value). Further, the effect additions of TerraZyme chemical in various dosages to soil were observed in terms of their modified proctor compaction, UCS and CBR values. The curing effect on UCS and CBR was investigated. The structural design of pavement for the high-volume roads (as per IRC:37-2018) is proposed by strengthening the conventional subgrade soil layer with TerraZyme and the pavement analysis is carried out.

This study of the laser powder bed fusion (LPBF) of γ′-strengthened Ni superalloy CM247LC focuses on the development of a melt pool temperature model to predict crack density within the alloy. This study also analyzes spatter and elemental evaporation, which might cause defects and inhomogeneities, at different melt pool temperatures. The melt pool temperature model provides more accurate predictions than the widely used energy density model. Spatter particles were collected and characterized to study their sizes and chemical compositions, compared with the virgin powder, recycled powder, and as-built samples, to probe the impact of their entrapment into the melt pool. This study also investigated Al evaporation, revealing that its extent does not correlate with the laser energy density and is believed to be rather limited by comparing the chemistry of the virgin powder and the build. Last, the impact of LPBF process parameters on the formation of these inhomogeneities, and accordingly crack formation, was studied using finite element analysis by estimating the maximum melt pool temperature and correlating it with the formation of the microstructural inhomogeneities. The morphology of the various cracking modes was associated with the process parameters.

The effect of axial static magnetic field (ASMF) on inclusion removal during the magnetically controlled electroslag remelting M2 high-speed-steel was investigated. The results showed that the application of ASMF can significantly increase the inclusion removal efficiency, especially for the inclusions larger than 20 μm. The reason for the accelerated removal of inclusions was attributed to the alternating Lorentz force and the magnetically controlled spin-vibration induced in the liquid melt film after the application of ASMF.

Global wood resources have been in short supply for a long time, whereas corn straw resources are abundant. To effectively alleviate the shortage of wood resources and the harm caused by straw burning, this paper developed corn straw biomass integrated material substitute wood materials. Corn straw biomass integrated material is a new type of material produced by a new reorganization and integration process of corn straw, which can replace wood as a structural material in construction engineering. In this paper, the mechanical properties of the axial compression components of the three integrated methods of parallel texture integration, vertical texture integration, and combination texture integration of corn straw biomass integrated material are studied. Through experimental research on the corn straw biomass integrated material, the failure modes and bearing capacity of different integration methods are compared. The straw fiber characteristics of the failure surface of the axial compression component are observed on a mesoscopic scale. The axial compression failure mechanism is then analyzed and determined, and the optimal integrated method for the axial compression component of corn straw biomass integrated material is proposed. Strong theoretical support is provided for further research and application of corn straw biomass integrated material structural components, and a reliable reference for research on new sustainable biomass building materials is given.