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The main objective of this research is to conduct an experimental investigation of the bimetallic material formed by 316LSI stainless steel and S275JR structural steel, produced via hybrid wire arc additive manufacturing technology with cool metal transfer welding and machining, and with the objective of being able to reduce the industrial cost of certain requirements for one of the materials. A methodological investigation has been carried out starting with welding beads of 316LSI on S275JR plates, followed by overlapping five beads and conducting final experiments with several vertical layers, with or without intermediate face milling. The results achieved optimal bead conditions for wire speeds of 4 m/min and 5 m/min at a travel speed of 400 mm/min. Overlap experiments show that the best deposition results are obtained with an overlap equal to or greater than 28%. Cooling time does not significantly influence the final geometry of the coatings. Regarding metallographic analysis, the filler material presents an austenitic columnar structure. In the base material, a bainitic structure with inferred grain refinement was detected in the heat-affected zone. An increase in hardness is observed in the heat-affected zone. In the results obtained from the tensile tests of the bimetallic material, an increase in mechanical strength and yield strength is observed in the tested specimens. [ABSTRACT FROM AUTHOR]

The topography of surfaces produced by metal additive manufacturing is a challenge for optical measurement systems such as focus variation microscopes. These irregularities can lead to artifacts, such as incorrectly measured protrusions or spikes, hampering reliable topographic characterization. In order to eliminate this problem, we introduce a new algorithm based on dual convolving a vertical Sobel operator with cross sections of an image stack parallel to the scanning direction of the so-called depth scan. This has proven beneficial in order to distinguish the focus region from out-of-focus areas where outliers are frequently detected. This paper introduces a method for deriving self-adaptive thresholds from the convolution result and compares the effects of different operators in creating self-adaptive thresholds. Additionally, a simulation model of focus variation microscopy is introduced to validate both the measuring system and the proposed algorithm, thereby enhancing the overall performance of focus variation microscopy. Finally, comparisons of measurement results on rough metal additive manufacturing workpieces with and without self-adaptive thresholds are discussed to demonstrate the algorithm's effectiveness.The utilization of self-adaptive thresholds demonstrably reduces the uncertainty range in roughness parameter calculations. For example, in the case of an additive manufactured metal sample due to outlier elimination, the S z roughness value reduces from 543 µm to 413 µm. [ABSTRACT FROM AUTHOR]

To investigate the mechanical properties and microstructure evolution of P92 steel during long-term service, the operated P92 main steam pipes from the first ultra-supercritical units in China were sectioned into samples representing various service durations and stresses (0# (as-received state, 1# (82,000 h, 67.3 MPa), 2# (85,000 h, 78.0 MPa), and 3# (100,000 h, 80.3 MPa)). Thereafter, a comprehensive assessment of their mechanical properties, including tensile strength, impact, hardness, and creep resistance, as well as a detailed microstructure analysis, was carried out. The effect of stress on the aging of material properties during operation is discussed. The results show that the circumferential stress caused by the increase in the internal steam pressure can significantly promote the creep life consumption of P92 steel, resulting in the degradation of mechanical properties and the expedited aging of the microstructure. The Rp0.2 and Rm of the P92 main steam pipe at room temperature and 605 °C decreased with the service time increase, reflecting the influence of stress in operation, which is expected to be used for the residual life evaluation of P92 steel. The relationship between the impact absorption energy (FATT50), Brinell hardness, and the operating time of P92 operating pipes is non-monotonic, indicating that these parameters are not sensitive indicators of material aging due to stress. The evaluation of performance degradation in P92 operating pipes due to stress-induced aging is not reliably discernible through optical metallography alone. To achieve a thorough assessment, the use of transmission electron microscopy (TEM) is essential. [ABSTRACT FROM AUTHOR]

42CrMo4-type steel grades are widely used in a great variety of components that require ad hoc mechanical properties. However, due to the dimensions of large components and the previous thermomechanical treatments, the presence of heterogeneities in the chemical compositions are expected to impact those mechanical properties. In the present work, a detailed analysis of phase transformation behavior upon cooling was carried out through a dilatometry test on samples of 42CrMo4 belonging to a component that has a non-homogeneous chemical distribution. The analysis of the dilatation signals and the quantitative metallography shows a rather complex behavior depending on the cooling rate as well as on the region of observation. Two different phase transformation models based on Li's approach were applied to the present composition to determine the CCT curve as well as the fraction of the microconstituents. An extensive discussion was carried out on some aspects about Kirkaldy-based approaches that need to be improved so as to attain more reliable quantitative results when modeling phase transformations in heterogenous systems. [ABSTRACT FROM AUTHOR]

The works in the field of radiation materials science of target materials of neutron sources based on the subcritical assemblies controlled by linear accelerators of electrons or protons, so-called accelerator driven systems (ADS), are reviewed. Now, electronuclear ADS systems are the prototype of safe nuclear reactors of the 5th generation. In connection with the physical start-up of the neutron source facility of the National Scientific Centre ‘Kharkiv Institute of Physics and Technology’ of the N.A.S. of Ukraine (NSC ‘KhIPT’ NASU), the target of which is fabricated from powdered tungsten covered with tantalum, the issues of preparation technology, construction, and physical and mechanical properties of W–Ta materials of targets in non-irradiated and irradiated states are considered. The nuclear-physical processes of radiation damage to the target during co-irradiation of it with both neutrons of a subcritical assembly and high-energy e- and γ-beams are analyzed. The target resources of ADS systems are estimated. As noted, the difficulty of predicting the ‘survivability’ of the W–Ta target also relates to the fact that, except for the works carried out at the NSC ‘KhIPT’ NASU in 70–90th of the last century, there are no experimental works in the world on the radiation damage of reactor materials by high-energy electrons with an energy of 100 MeV and above.

Herein, hierarchically structured microgrid frameworks of Co3O4 and carbon composite deposited on reduced graphene oxide (Co3O4@C/rGO) are demonstrated through the three‐dimensioinal (3D) printing method, where the porous structure is controllable and the height and width are scalable, for dendrite‐free Na metal deposition. The sodiophilicity, facile Na metal deposition kinetics, and NaF‐rich solid electrolyte interphase (SEI) formation of cubic Co3O4 phase are confirmed by combined spectroscopic and computational analyses. Moreover, the uniform and reversible Na plating/stripping process on 3D‐printed Co3O4@C/rGO host is monitored in real time using in situ transmission electron and optical microscopies. In symmetric cells, the 3D printed Co3O4@C/rGO electrode achieves a long‐term stability over 3950 at 1 mA cm−2 and 1 mAh cm−2 with a superior Coulombic efficiency (CE) of 99.87% as well as 120 h even at 20 mA cm−2 and 20 mAh cm−2, far exceeding the previously reported carbon‐based hosts for Na metal anodes. Consequently, the full cells of 3D‐printed Na@Co3O4@C/rGO anode with 3D‐printed Na3V2(PO4)3@C‐rGO cathode (≈15.7 mg cm−2) deliver the high specific capacity of 97.97 mAh g−1 after 500 cycles with a high CE of 99.89% at 0.5 C, demonstrating the real operation of flexible Na metal batteries. [ABSTRACT FROM AUTHOR]

The flow stress of a metallic material is one of the important parameters to measure the plastic deformability of a material. The quality of the microstructure reflects the forming quality and reliability of a part. Therefore, a high-quality flow stress and microstructure models are very important for the optimization of the process parameters. The flow stress and dynamic recrystallization (DRX) law of the 40CrNiMo axle steel were obtained by performing a thermal simulation compression test and metallography examination. The effects of deformation temperatures, strain rates, and initial grain sizes on the DRX and flow curves were discussed. A strain-compensated Arrhenius-type flow stress equation was established. Considering the influence of the deformation temperatures, strain rates, and initial grain sizes on DRX, a kinetic model and an average grain size evolution model for DRX were established. Statistical and finite element (FE) simulation methods were used to verify the predictability and validity of the flow stress and the microstructure models, which provides an important basis for the study of hot forming of the 40CrNiMo steel. [ABSTRACT FROM AUTHOR]

This article presents a comparative analysis of the crucial physical properties of electrically conductive components made of pure copper, produced by various additive manufacturing technologies such as binder jetting (BJ) and direct metal laser sintering (DMLS). The comparison concerned the assessment of critical parameters important from the application point of view, such as: electrical conductivity, hardness, yield point, microstructure and the occurrence of internal material defects. Same-sized components made in a conventional casting and subtractive method (machining) were used as a reference material. Comprehensive tests and the comparison of a wide range of parameters allowed us to determine that among the selected methods, printing using the DMLS technique allowed for obtaining arcing contact with mechanical and electrical parameters very similar to the reference element. Therefore, the obtained results showed the possibility of using the copper elements made by additive manufacturing for the switching and protection devices used in electrification and energy distribution industrial sectors. [ABSTRACT FROM AUTHOR]

The martensitic transformations in Cu–38Zn and Cu–39.5Zn (wt %) alloys with the shape memory effect have been studied using a combination of transmission and scanning electron microscopy, optical metallography, and X-ray diffraction analysis. When examining specimen upon cooling to low temperatures in the transmission electron microscope column, the features of martensite morphology and fine structure, as well as of electron microdiffraction in the alloys, have been ascetained. The structural types of martensite phases (3R) and (2H) have been identified in Cu–38Zn alloys, as well as (9R) and (2H), in Cu–39.5Zn alloys. The proposed crystallographic models of martensitic rearrangement in the alloys are based on an analysis of X-ray and electron diffraction, including diffuse electron scattering, as well as on the packing defects of the internal substructure of martensite. [ABSTRACT FROM AUTHOR]

As anthropogenic activities have facilitated the spread of heavy metals into the environment, plants have been identified that may have the ability to tolerate exposure to high levels of these metals. Industrial hemp (Cannabis sativa L.) has been suggested as potentially having the ability to accumulate elevated concentrations of some contaminants from soils, including cadmium (Cd), a heavy metal that has been linked to serious health risks to humans. Therefore, there is an interest to document the ability of hemp to tolerate exposure to Cd to determine if there is a risk when products for medicinal consumption are made from the hemp plant. The objectives of this study were to perform histochemical localization of Cd at the cellular level and document potential changes in plant tissues in response to hemp exposure. Plants were grown in hydroponic solutions for 4 weeks and then exposed to either 0 or 10 mg·L-1 Cd for 17 days and harvested. There were no differences in dry weights (dw) of leaves, stems, and roots among treated and control 17 days after treatment (DAT). However, plants exposed to 10 mg·L-1 Cd had Cd concentrations of 1448.0 mg·kg-1 dw in roots and 23.2 mg·kg-1 dw in leaves at 17 DAT, whereas Cd was not detected in roots or leaves of control plants. On staining with dithizone, Cd was primarily localized in leaf epidermis, mesophyll, and trichomes, and in root rhizodermis, cortex, and pericycle in hemp plants exposed to 10 mg·L-1 Cd. Image analysis was able to further quantify these results based on area stained. Our results suggest that Cd is primarily accumulated throughout hemp roots, with lesser amounts translocated to the leaves, where it may be localized in the epidermis and trichomes. [ABSTRACT FROM AUTHOR]

The additive manufacturing (AM) is a relative new manufacturing process that belongs to the fourth industrial revolution, thus yielding new challenges that are worth the study in terms of reliability. In that sense, this work presents a comparative study of as printed and optimally heat-treated 1.2709 maraging steel manufactured by laser powder bead fusion (LPBF) AM process. The results suggest that parts were sound in terms of visual inspection and microstructural analysis. In the case of mechanical properties, the results suggest that the highest variability occurred after the heat treatment. The high cycle fatigue samples revealed a fracture without exhibiting a considerable amount of plastic deformation. On the other hand, the low cycle fatigue results revealed that at 1% strain the optimally heat-treated specimens have lower fatigue life due to the presence of surface discontinuities and the reduction of ductility after the heat treatment. [ABSTRACT FROM AUTHOR]

This study explores the microstructural characterization of pearlite phase transformation in high-strength low-alloy API X60 steel, which is used in pipelines. Understanding the formation, phase percentages, and morphology of the pearlitic phase is crucial since it affects the mechanical properties of the considered steel. In this research, a phase-field model, particularly the Cahn-Hilliard approach, was used in order to simulate the formation and morphology of the pearlite phase in response to different heat treatments. Both double- and triple-well potentials were considered for comprehensively studying pearlite's morphology in the simulations. The simulation results were then compared with experimental outcomes obtained by metallography and field-emission scanning electron microscopy analyses. Considering the doublewell potential can help simulate only two phases, ferrite and cementite, which is less compatible with the experiment results than the triple-well potential, which gives the possibility of simulating a three-phase microstructure, ferrite, cementite, and austenite, and a better match with experimental data. The study revealed that as the cooling rate increases, the interlamellar spacing and layer thickness decrease. Additionally, the difference between experimental and simulation results using triple-well potential was approximately ~10%. Therefore, triple-well potential formulation predictions have better agreements with experimental results for the development circumstance of pearlitic structures. [ABSTRACT FROM AUTHOR]

The microstructure and phase composition of Ti–6Al–4V alloy specimens produced by wire electron-beam additive manufacturing (EBAM) technology and selective laser melting (SLM) method after exposure to an electron beam, simulating electron-beam welding, have been investigated by X-ray diffraction analysis, optical metallography, and transmission electron microscopy. In the electron beam exposure zone of SLM specimens, in contrast to EBAM specimens, it was observed that the transverse dimensions of anisotropic primary β grains and α/α′ phase plates increased and inside α/α′ phase plates, submicrocrystalline α phase grains and nanocrystalline α′′ phase were formed. The different character of microstructure and, accordingly, microhardness changes in the weld zone and heat-affected zone in comparison with the base metal is caused by the different cooling rate of the melt bath in the weld zones of EBAM and SLM specimens. In the SLM specimen, the cooling rate of the melt bath is less than that observed in the EBAM specimen. This discrepancy can be attributed to the fact that due to the finer needle-like α′ martensitic structure, the thermal conductivity in the base metal of the SLM sample is less than that in the base metal of the EBAM sample. [ABSTRACT FROM AUTHOR]

The works in the field of radiation materials science of target materials of neutron sources based on the subcritical assemblies controlled by linear accelerators of electrons or protons, so-called accelerator driven systems (ADS), are reviewed. Now, electronuclear ADS systems are the prototype of safe nuclear reactors of the 5th generation. In connection with the physical start-up of the neutron source facility of the National Scientific Centre 'Kharkiv Institute of Physics and Technology' of the N.A.S. of Ukraine (NSC 'KhIPT' NASU), the target of which is fabricated from powdered tungsten covered with tantalum, the issues of preparation technology, construction, and physical and mechanical properties of W-Ta materials of targets in non-irradiated and irradiated states are considered. The nuclear-physical processes of radiation damage to the target during co-irradiation of it with both neutrons of a subcritical assembly and high-energy e- and g-beams are analyzed. The target resources of ADS systems are estimated. As noted, the difficulty of predicting the 'survivability' of the W-Ta target also relates to the fact that, except for the works carried out at the NSC 'KhIPT' NASU in 70-90th of the last century, there are no experimental works in the world on the radiation damage of reactor materials by high-energy electrons with an energy of 100 MeV and above. [ABSTRACT FROM AUTHOR]

Finds of early medieval Schlingen-type swords are mostly concentrated in present-day southern Germany, where they are known from a number of graves dating to the end of the late Merovingian period. On the contrary, these swords are completely absent in contexts of the early Carolingian and Great Moravian periods. This paper presents a new find of Schlingen-type sword from Vlčí Pole in the northeastern part of Central Bohemia and its archaeometric analysis. We consider the sword from Vlčí Pole to be the only unambiguous find of a fully preserved long-bladed weapon of the late 7th to 8th century in Bohemia. As it is one of the few late Merovingian swords to have been examined using X-ray computed tomography and metallography, it also contributes to a general understanding of phenomena such as the development of the use of pattern-welded marks and blades with cutting edges of hardened steel.

The upcoming energy transition requires not only renewable energy sources but also novel electricity storage systems such as batteries. Despite Li-ion batteries being the main storage systems, other batteries have been proposed to fulfil the requirements on safety, costs, and resource availability. Moving away from lithium, materials such as sodium, magnesium, zinc, and calcium are being considered. Water-based electrolytes are known for their improved safety, environmentally friendliness, and affordability. The key, however, is how to utilize the negative metal electrode, as using water-based electrolytes with these metals becomes an issue with respect to oxidation and/or dendrite formation. This work studied magnesium, where we aimed to determine if it can be electrochemically deposited in aqueous solutions with alginate-based additives to protect the magnesium. In order to do so, atomic force microscopy was used to research the morphological structure of magnesium deposition at the local scale by using a probe—the tip of a cantilever—as the active electrode, during charging and discharging. The second goal of using the AFM probe technology for magnesium deposition and stripping was an extension of our previous study in which we investigated, for lithium, whether it is possible to measure ion current and perform nonfaradaic impedance measurements at the local scale. The work presented here shows that this is possible in a relatively simple way because, with magnesium, no dendrite formation occurs, which hinders the stripping process. [ABSTRACT FROM AUTHOR]

Hastinapur is one of the prominent painted grey ware archaeological sites in the Ganga Valley. In the present communication, we report the results of the metallurgical analysis of the excavated slag samples from the site. The existence of a large number of iron objects for this site can be dated between c. 6th century BCE and c. 16th century CE, with early iron from the 8th century BCE. The morphological, microstructural and elemental studies of the excavated slag indicate a high amount of carbon in iron, indicating crucible carburization activities at this site. In addition, the presence of niobium, cobalt, etc. in the slag indicates the usage of non-traditional iron ores in the primary ironmaking stage. [ABSTRACT FROM AUTHOR]

An in-depth understanding of the fracture behavior and mechanism of metallic shells under internal explosive loading can help develop material designs for warheads and regulate the quantity and mass distribution of the fragments formed. This study investigated the fragmentation performance of a new high-carbon silicon-manganese (HCSiMn) steel cylindrical shell through fragment recovery experiments. Compared with the conventional 45Cr steel shell, the number of small mass fragments produced by the HCSiMn steel shell was significantly increased with a scale parameter of 0.57 g fitted by the Weibull distribution model. The fragmentation process of the HCSiMn shell exhibited more brittle tensile fracture characteristics, with the microcrack damage zone on the outer surface being the direct cause of its high fragmentation. On the one hand, the doping of alloy elements resulted in grain refinement by forming metallographic structure of tempered sorbite, so that microscopic intergranular fracture reduces the characteristic mass of the fragments; on the other hand, the distribution of alloy carbides can exert a "pinning" effect on the substrate grains, causing more initial cracks to form and propagate along the brittle carbides, further improving the shell fragmentation. Although the killing power radius for light armored vehicles was slightly reduced by about 6%, the dense killing radius of HCSiMn steel projectile against personnel can be significantly increased by about 26% based on theoretical assessment. These results provided an experimental basis for high fragmentation warhead design, and to some extent, revealed the correlation mechanism between metallographic structure and shell fragmentation. [ABSTRACT FROM AUTHOR]

This study presents a microstructural investigation of the printing parameters of an AlSi7Mg0.6 alloy produced by powder bed fusion (PBF) using laser beam melting (LB/M) technology. The investigation focused on the effects of laser power, exposure velocity, and hatching distance on the microhardness, porosity, and microstructure of the produced alloy. The microstructure was characterized in the plane of printing on a confocal microscope. The results showed that the printing parameters significantly affected the microstructure, whereas the energy density had a major effect. Decreasing the laser power and decreasing the hatching distance resulted in increased porosity and the increased participation of non-melted particles. A mathematical model was created to determine the porosity of a 3D-printed material based on three printing parameters. Microhardness was not affected by the printing parameters. The statistical model created based on the porosity investigation allowed for the illustration of the technological window and showed certain ranges of parameter values at which the porosity of the produced samples was at a possible low level. [ABSTRACT FROM AUTHOR]

The foundation of materials science and engineering is the establishment of process–microstructure–property links, which in turn form the basis for materials and process development and optimization. At the heart of this is the characterization and quantification of the material's microstructure. To date, microstructure quantification has traditionally involved a human deciding what to measure and included labor-intensive manual evaluation. Recent advancements in artificial intelligence (AI) and machine learning (ML) offer exciting new approaches to microstructural quantification, especially classification and semantic segmentation. This promises many benefits, most notably objective, reproducible, and automated analysis, but also quantification of complex microstructures that has not been possible with prior approaches. This review provides an overview of ML applications for microstructure analysis, using complex steel microstructures as examples. Special emphasis is placed on the quantity, quality, and variance of training data, as well as where the ground truth needed for ML comes from, which is usually not sufficiently discussed in the literature. In this context, correlative microscopy plays a key role, as it enables a comprehensive and scale-bridging characterization of complex microstructures, which is necessary to provide an objective and well-founded ground truth and ultimately to implement ML-based approaches. [ABSTRACT FROM AUTHOR]

2219-T87 is a precipitation hardenable aluminum-copper alloy which sees wide use in structural aerospace components. Thick panels of this alloy are joined via self-reacting friction welding (SRFSW); however, this thermomechanical process can result in significant loss of the alloy's strengthening precipitates and large residual stresses which are detrimental to mechanical behavior and performance. High-resolution maps of the residual strain and stress states along the normal, transverse, and longitudinal directions of 2219-T87 SRFSW were obtained using neutron diffraction measurements. Residual stress had the highest tensile value in the heat-affected zone (HAZ) and the largest compressive stress in the base metal region of the normal and transverse directions. Line profile residual stress distributions displayed an "M"-shaped distribution in each direction with the longitudinal direction being the most pronounced while 2D residual stresses displayed an hourglass-shaped pattern. Average maximal longitudinal residual stress values ranged from 60.6 to 85.6% of yield. Microhardness testing across the transverse weld section produced a "V"-shaped curve with slight hardness recovery in the stir zone. Maximal and minimal microhardness values were observed in the base metal (154 HV) and thermomechanically affected zone (82 HV), respectively. Microstructural evolution was recorded using optical microscopy and showed decreasing grain size from the HAZ to the stir zone. [ABSTRACT FROM AUTHOR]

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

An experimental metallographic method for determining strain distribution in a cold formed workpiece is presented in this paper. The method, based on the dependence of recrystallized grain size on prior deformation, was applied to a bulk formed element made of low carbon steel. Strain distribution was obtained by the calibration curve which gives the relation between recrystallized grain size and prior deformation. To determine strain values, the average grain size was measured in the longitudinal cross-section of the formed element. To accurately differentiate deformation zones, additional observation of carbides and nonmetallic inclusions morphology was utilized, also. The grain size and strain noticeably differ through the cross-section. It is observed that in the middle part, material flows freely through the die opening without significant deformation. From this zone, strain increases gradually, reaching the highest value at the contact surface of the die slope, while the top part flows radially having intermediate values of strain.

This publication presents the chemical compositions of carbon reducers used in the production of ferroalloys, with particular emphasis on the content of Al, Ca, Mg, Mn, Cr, Ti, P, or S in their mineral substances. A certain amount of these elements is transferred to the produced alloys, creating inclusions and precipitations in the metal structure. Most of them are undesirable and adversely affect the final effect of the production process. The work includes sample images of the microstructure of alloys, the chemical compositions of the samples at the test point, and diffragrams. On the basis of the obtained metallographic data, technological observations are made, especially of the crushing process and the amount of grain fractions obtained. [ABSTRACT FROM AUTHOR]

An experimental metallographic method for determining strain distribution in a cold formed workpiece is presented in this paper. The method, based on the dependence of recrystallized grain size on prior deformation, was applied to a bulk formed element made of low carbon steel. Strain distribution was obtained by the calibration curve which gives the relation between recrystallized grain size and prior deformation. To determine strain values, the average grain size was measured in the longitudinal cross-section of the formed element. To accurately differentiate deformation zones, additional observation of carbides and nonmetallic inclusions morphology was utilized, also. The grain size and strain noticeably differ through the cross-section. It is observed that in the middle part, material flows freely through the die opening without significant deformation. From this zone, strain increases gradually, reaching the highest value at the contact surface of the die slope, while the top part flows radially having intermediate values of strain. [ABSTRACT FROM AUTHOR]

This article used Mn-Mo-Cr-B low-carbon bainitic steel as the experimental material. The continuous cooling transformation curve of the steel during continuous cooling was determined using a Gleeble-1500D thermal simulation test machine, and a corresponding phase transformation model for bainitic steel during continuous cooling was established. The influence of different cooling rates and final cooling temperatures on the microstructure and mechanical properties of the steel was investigated. Employing metallography, SEM, and EBSD techniques, the microstructure, crystallographic orientation, and grain boundary angle distribution of the low-carbon bainitic steel were explored, and their relationship with the steel's strength and toughness was studied. The research findings reveal that varying cooling rates and final cooling temperatures impact the phase transformation process and microstructure of the steel, consequently affecting its mechanical properties indirectly. With increasing cooling rate, the diffusion and fineness of martensite increase, and the quantity of lath bainite grows while the laths become finer. Elevated final cooling temperatures lead to larger martensiticaustenitic (MA) islands and reduced lath bainite quantity, causing the laths to become wider. Through analysis of the substructure of bainitic steel, it was determined that the bainite organization in the tested steel comprises primary austenite grains, lath packet, and lath block in succession. Lath packets are composed of lath blocks with different orientations, where lath size predominantly controls strength. Finer lath size corresponds to higher strength, and the influence of substructure on toughness is comparatively minor. [ABSTRACT FROM AUTHOR]

Multiple GH4169 samples were prepared with the regulation of the forming process of selective laser melting(SLM), particularly in laser power and scanning speed. The microstructure including defect morphology and distribution was observed by using metallography. The sample porosity was acquired using X-ray computed tomography(XCT), and the three-dimensional characteristics of defect were also statistically studied. The correlation of forming process and defect characteristics was finally analyzed. The results show that when the optimized energy input density is 59.1 J/mm3, the forming samples share common features of overlapping melting trace with a tidy morphology, randomly distributed pores with sizes of less than 30 -m and the density is as high as 99.9998%. Within a narrow window of forming process(220-300 W, 700-1300 mm/s), the scanning speed takes more responsibility for the sample density, and its high value tends to form extremely irregular lack of fusions(LOFs) that distribute in the overlap of melting trace. As deviating from the optimized process, the number of defects has increased, and some defect sizes are also greater than 30 ^m. The shapes of pores and LOFs respectively formed by high laser power or high scanning speed are closely related to their own sizes, that is, the larger the size, the more irregular the shape, which produces more detrimental effects than regular pores. [ABSTRACT FROM AUTHOR]

Cast (real) damascus steel (so-called “wootz”) is an ancient tool/weapon material. Due to relatively high carbon amounts, the wootz is hard to forge (or other hot-forming shaping). In some cases, the forging of wootz is impossible. During forging, cracks are often created that lead to absolutely disintegration of bulk material. In this paper is given one relationship between wootz microstructure and the forging impossibility.

This article presents a comparative analysis of the crucial physical properties of electrically conductive components made of pure copper, produced by various additive manufacturing technologies such as binder jetting (BJ) and direct metal laser sintering (DMLS). The comparison concerned the assessment of critical parameters important from the application point of view, such as: electrical conductivity, hardness, yield point, microstructure and the occurrence of internal material defects. Same-sized components made in a conventional casting and subtractive method (machining) were used as a reference material. Comprehensive tests and the comparison of a wide range of parameters allowed us to determine that among the selected methods, printing using the DMLS technique allowed for obtaining arcing contact with mechanical and electrical parameters very similar to the reference element. Therefore, the obtained results showed the possibility of using the copper elements made by additive manufacturing for the switching and protection devices used in electrification and energy distribution industrial sectors.

Abstract Excavations at the Chalcolithic site Fazael in the central Jordan Valley uncovered a large number of metal items, many of them polymetallic copper alloys cast in the lost wax technique. Metallography and SEM–EDS analysis on a subset of the assemblage confirm previous notions of the lost wax metallurgy in the Chalcolithic Southern Levant but extend them significantly in three aspects: The Fazael metal assemblage is slightly depleted in its arsenic content compared to metal assemblages from other sites, silt-sized quartz inclusions in unalloyed and polymetallic copper items, and the presence of unalloyed copper inclusions. These latter provide the earliest direct evidence for mixing of different metal types in West Asia, potentially alloying or recycling.

Archaeological research at Hoeke, a Late Medieval outer harbour of Bruges (Belgium), has revealed large quantities of iron slags, fuel and other remains of iron working. Archaeometrical study has provided an enhanced insight into the historic iron working process, a craft activity which had up till now remained completely unknown in one of the largest economic hubs of medieval Europe. Several petrological, mineralogical and geochemical analytical methods have been applied for this purpose. The metallographic analysis was performed using reflected light optical microscopy, while the mineralogical composition of the slags was characterized X-ray Diffraction (XRD) Spectrometry. Macroscopic identification of plano-convex bottom slag and hammerscales, combined with the geochemical data pointed out that the examined slag is indicating smithing activity, while no traces for iron ore melting were discovered. [ABSTRACT FROM AUTHOR]

Accumulating interest from academia and industry, the part of quality assurance in metal additive manufacturing (AM) is achieving incremental recognition owing to its distinct advantages over conventional manufacturing methods. In this paper, we introduced a convolutional neural network, YOLOv8 approach toward robust metallographic image quality inspection. Metallographic images accommodate key information relating to metal properties, such as structural strength, ductility, toughness, and defects, which are employed to select suitable materials for multiple engineering execution. Therefore, by comprehending the microstructures, one can understand insights into the behavior of a metal component and make predictive assessments of failure under specific conditions. Deep learning-based image segmentation is a robust technique for the detection of microstructural defects like cracks, inclusion, and gas porosity. Therefore, we improvise the YOLOv8 with dilated convolution mechanisms to acquire automatic micro-structure defect characterization. More specifically, for the first time, the YOLOv8 algorithm was proposed in the metallography dataset from additive manufacturing of steels (Metal DAM) to identify defects like cracks and porosity as a novel approach. A total of 414 images from ArcelorMittal engineers were used as an open-access database. The experimental results demonstrated that the YOLOv8 model successfully detected and identified cracks and porosity in the metal AM dataset, achieving an improved defect detection accuracy of up to 96% within just 0.5 h compared to previous automatic defect recognition processes. [ABSTRACT FROM AUTHOR]

This paper deals with the evaluation of material properties of the additively manufactured austenistic alloy 08CH18N10T, which is widely used in the Czech Republic nuclear power plants Temelín and Dukovany and other VVER reactors around the world. For purposes of utilization of additive manufacturing technologies for nuclear core components fabrication, two sets of samples were prepared from horizontally and vertically L-DED printed blocks from 08CH18N10T material. Experiments such as microstructure analysis, porosity and Vickers hardness were then performed on L-DED printed and heat-treated 08CH18N10T material, and the obtained material properties were then compared with the properties of L-DED printed 08CH18N10T material without heat-treatment for examination of its effect and also with material properties of conventionally made 08CH18N10T material. [ABSTRACT FROM AUTHOR]

Thermal simulation is an interesting method to reproduce different regions of the heat-affected zone (HAZ) in specimens with dimensions proper to perform microstructural investigations, corrosion resistance and mechanical tests. In this work, different regions of the HAZ of duplex UNS S32205 and superduplex UNS S32750 stainless steels were reproduced using a Gleeble machine. For each material, thermal cycles with peak temperatures of 800, 1000, 1200 and 1350 °C were reproduced in order to evaluate the microstructure, pitting resistance, hardness and microhardness of the phases. It was found that the critical pitting temperature (CPT) was reduced in specimens processed with a peak temperature of 1350 °C in comparison with the base metals, while with peak temperatures of 800 and 1000 °C there was an increase in the CPT. Secondary austenite precipitation was identified in specimens with peak temperatures 800 and 1000 °C, but this phase did not impar the pitting resistance. Intense chromium nitrides precipitation and increase in the ferrite phase content were the main microstructural changes observed with peak temperature 1350 °C. The duplex steel undergone higher ferritization than the superduplex. The CPT was reduced with the chromium nitride precipitation, but the microhardness of the ferrite was not affected by these particles. [ABSTRACT FROM AUTHOR]

Metallic fuels have seen increased interest for future sodium fast reactors due to their material properties: high thermal conductivities and advantageous neutronic properties allow for greater fission densities. One drawback to typical metallic fuels is zirconium redistribution, which impacts this advantageous material and its neutronic properties. Unfortunately, the processes behind zirconium migration behavior are understood using first principles, so before these fuels are implemented in future fast reactors, characterization and fuel qualification regimes must be completed. These activities can be supported through the use of robust modeling using the most accurate empirical models currently available to fuel researchers around the world. The tool that allows researchers to model this complex coupled thermo-mechanical behavior and nuclear properties is BISON. Additionally, BISON model parameters need to be compared against PIE measurements. The current work utilizes two fuel pins from EBR-II experiment X441 to optimize various model parameters, including porosity correction factor, thermal conductivity, phase transition temperature, and diffusion coefficient multipliers, before implementing the final model for seven fuel pins with differing characteristics. To properly evaluate the BISON simulations, the results are compared to PIE metallography data for each fuel pin, to ensure the zirconium redistribution is properly reflected in the simulation results. Six out of seven analyzed fuel pins demonstrate good agreement between the metallography images and BISON results, showing alignment of the Zr-rich, Zr-depleted, and moderately Zr-enriched zones at various axial heights along the fuel pins. Further work is needed to refine the model parameters for general pin use. [ABSTRACT FROM AUTHOR]

The coarse-grain heat-affected zone (CGHAZ) is often the most fragile part of the weld region due to hard phases and coarse grains generated during the welding. Characterization of the mechanical properties and fracture resistance of the CGHAZ is a vexing problem because the CGHAZ is usually not big enough for the fabrication of specimens for traditional tests. In this study, simulated CGHAZ was produced for welds of Q355D steel by a thermal simulation technique. The peak temperature was 1,350°C for all thermal simulations and different cooling rates were designed, i.e., t8/5=30 s , 60 s, 90 s, 120 s, and 180 s, to investigate the effect of the cooling rate on the solid-state phase transformation of the steel. The similarity of the simulated CGHAZ with t8/5=180 s to the CGHAZ from the weldment was verified by metallography examination and depth sensing indentation tests. Then, the mechanical properties of the simulated CGHAZ were characterized by Charpy impact tests and tension coupon tests. The simulated CGHAZ has distinctly higher yield stress and tensile stress, but lower elongation, section reduction, and Charpy impact energy than the base metal (BM) of the Q355D steel. Parameter η , representing fracture resistance in the void growth model, was calibrated for the simulated CGHAZ through tests on smooth notched tensile specimens and complementary finite element analysis. Comparison of parameter η indicates that the fracture resistance of the simulated CGHAZ is about 5.7% lower than that of the BM of the Q355D steel. [ABSTRACT FROM AUTHOR]

Introduction: Metallographic replication has become an effective method in the study of residual life, to the point where normative documents of wide international application have been developed, such as the ASTM E1351-01 standard. Although this standard contemplates the use of scanning electron microscopy, it does not yet consider the use of transmission electron microscopy, despite it being convenient and feasible from a practical point of view. Objective: To establish the microstructural condition of the material of a SA335 Grade P11 steel steam pipe with over 20 years of service at 480 °C, using metallographic replication. Materials and Methods: Direct extraction replication was applied, combined with TEM. Results and Discussion: The microstructure present in the steel was of the ferrite-perlite type. The ferrite exhibited regular and uniformly sized intergranular and intragranular precipitation (approximately between 50 and 100 nm). At the service temperature, the ferrite would have reached, with respect to M2C (88% Mo, 6% Fe, and 6% Cr), a composition close to equilibrium after a process of nucleation and growth of M2C. Conclusions: The SA335 Grade P11 steel, after more than 20 years in service at 480 °C, exhibited a ferrite-perlite microstructure with intergranular and intragranular precipitation in the ferrite. The occurrence of competitive growth phenomenon due to the time and service temperature was evidenced. Metallographic replication, using MET, constitute an effective method to evaluate the microestructura of steam pipes. [ABSTRACT FROM AUTHOR]

While Ti6Al4V is one of the most used titanium alloys in the biomaterials field, it is not without its challenges and limitations, among which very important is the modulus mismatch with the bone. This modulus mismatch can lead to stress shielding potentially leading to bone resorption and implant loosening. Researchers continue to explore alternative materials and modifications to address this challenge and improve the performance of biomaterials. Two new fabricated titanium alloys Ti-10Al and Ti-4Fe are analyzed in this paper from corrosion and elastic modulus points of view. Metallography, microhardness, open circuit potential, DC electrochemical linear polarization, and Electrochemical Impedance Spectroscopy were performed. It was found that the corrosion resistance measurement for the Ti4Fe alloy is two orders of magnitude lower than for the Ti10Al alloy as determined by the equivalent circuit simulation, which is also supported by the similar disparity in the corrosion rate values for the two alloys which was determined using the DC method. The modulus of elasticity values were fairly close, hovering about 35GPa, and were lower than those of many commercial alloys. [ABSTRACT FROM AUTHOR]

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Monolith and bulk-structured samples of different densities have been obtained using selective laser melting on a Realizer SLM 100 3D-printer intended for metals. Their quality and structure have been estimated via metallography and scanning electron microscopy. The correlation has been established between the parameters of synthesis, namely, between the intertrack distance and layer thickness at a laser power of 200 W, on the one hand, and structural characteristics, on the other. Based on the experimental results, the optimum operating parameters of a 3D-printer were found to obtain the Al–Cu–Mg–Si samples with dispersed structure and high mechanical properties. The features of the synthesis of bulk-structured samples with cubic geometry of plotting have been studied, and the types of defects that affect the quality and mechanical properties of samples have been determined. [ABSTRACT FROM AUTHOR]

The process of convergence of copper thick-walled cylindrical shells under the action of an explosion is studied using the metallographic method. The explosion was initiated at eight points evenly spaced around a circle on the surface of the explosive surrounding the shell. At the intermediate stage of convergence, eight ejections were formed on the inner surface of the shell. The convergence of the shells into a cylinder is completed due to the expansion and closure of ejections. The formation of ejections is explained by the rise of plastic (cumulative) jets at the deformation front. Jets arise when adjacent deformation protrusions collide. Regions of localized deformation were detected in and around the ejections, which is associated with the method of initiating the explosion. It has been established that high-strain-rate deformation of copper during the convergence of shells is accompanied by the formation of a large number of twins. In the outer zones of the shells, there are more twins than in the inner ones. [ABSTRACT FROM AUTHOR]

The effect of Ca element on the microstructure evolution of the AZ91 magnesium alloy was investigated in this research. The magne-sium-aluminium alloy AZ91 was inoculated with the Emgesal® Flux 5 to refine its microstructure and also improve its microstructure. Six different concentrations of the Emgesal® Flux 5 content were tested, ranging from 0.1 to 0.6% wt., and compared to the baseline of the AZ91 alloy without inoculation. Melted metal was poured into a preheated metallic mould. Samples to test were achieved after turning treatment. Formed microstructure was assessed using an optical microscope. The microstructure was refined for every tested samples. Me-chanical properties such as tensile strength, elongation, Brinell hardness, Vickers microhardness, abrasion resistance and adhesive resistance were tested on the inoculated samples and compared to the non-inoculated AZ91. Introducing an Emgesal®Flux 5 inoculant caused a change in the tensile strength, elongation, Brinell hard-ness, Vickers microhardness, abrasive wear resistance as well as adhesive wear resistance in each examined concentration.

The foundation of materials science and engineering is the establishment of process–microstructure–property links, which in turn form the basis for materials and process development and optimization. At the heart of this is the characterization and quantification of the material’s microstructure. To date, microstructure quantification has traditionally involved a human deciding what to measure and included labor-intensive manual evaluation. Recent advancements in artificial intelligence (AI) and machine learning (ML) offer exciting new approaches to microstructural quantification, especially classification and semantic segmentation. This promises many benefits, most notably objective, reproducible, and automated analysis, but also quantification of complex microstructures that has not been possible with prior approaches. This review provides an overview of ML applications for microstructure analysis, using complex steel microstructures as examples. Special emphasis is placed on the quantity, quality, and variance of training data, as well as where the ground truth needed for ML comes from, which is usually not sufficiently discussed in the literature. In this context, correlative microscopy plays a key role, as it enables a comprehensive and scale-bridging characterization of complex microstructures, which is necessary to provide an objective and well-founded ground truth and ultimately to implement ML-based approaches.

ABSTRACTArchaeological research at Hoeke, a Late Medieval outer harbour of Bruges (Belgium), has revealed large quantities of iron slags, fuel and other remains of iron working. Archaeometrical study has provided an enhanced insight into the historic iron working process, a craft activity which had up till now remained completely unknown in one of the largest economic hubs of medieval Europe. Several petrological, mineralogical and geochemical analytical methods have been applied for this purpose. The metallographic analysis was performed using reflected light optical microscopy, while the mineralogical composition of the slags was characterized X-ray Diffraction (XRD) Spectrometry. Macroscopic identification of plano-convex bottom slag and hammerscales, combined with the geochemical data pointed out that the examined slag is indicating smithing activity, while no traces for iron ore melting were discovered.

INCOLOY alloy 800 is widely utilized in the outlet manifold bottom header (OMBH) inside a primary reformer at a fertilizer plant. Primary reformers in fertilizer plants usually work at high temperatures and pressures for long periods. In this work, solution annealing and normalization processes were conducted to improve the weldability of INCOLOY alloy 800 after operating for ten years. Characterizations of weldability properties were carried out through dye penetrant, X-ray fluorescence, hardness, X-ray diffraction (XRD), and metallography observations. The annealing and normalization results showed that the weldability of INCOLOY alloy 800 increased, indicating a significant reduction in cracks on the weld zone surface. Microstructure observations revealed that microcracks were not found on the weld joint surface after solution annealing. The maximum hardness value on the fusion zone was obtained at 187 VHN on normalizing, and the minimum hardness was obtained on the nontreatment sample 156.33 VHN. [ABSTRACT FROM AUTHOR]

Four ferrous objects, a winch, a heart-shaped shackle, a deadeye strap with a futtock plate, and a stud-link chain controller, that were retrieved from the Akko Tower shipwreck were studied by different methods, including conventional metallography, light microscopy, scanning electron microscopy with energy-dispersive spectroscopy, optical emission spectroscopy, microhardness measurements, and the novel field multi-focal metallography (FMM), in order to determine their composition, microstructure, and manufacturing methods. The results of FMM agree well with conventional destructive metallography. The winch drum was made of grey cast iron and its shaft was wrought iron; the heart-shaped shackle and the deadeye strap with a futtock plate were wrought iron; and the stud-link chain controller was grey cast iron similar in composition and microstructure to the winch. All the wrought iron items revealed a similar composition and microstructure. Based on the composition, microstructure, and manufacturing processes of the four items, it is suggested that they were manufactured in the mid-nineteenth century. The high quality of these items indicates that they were produced using controlled processes, probably in the same workshop. [ABSTRACT FROM AUTHOR]