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Plastic deformation and damage evolution in low-carbon cast steel containing non-metallic inclusions are analyzed experimentally and numerically. The cast steel was subjected to the heat treatment: normalizing, oil quenching and tempering. Tests were carried out at hydrostatic pressure of 500 MPa and 1 000 MPa. In the tensile test the tensile strength, elongation and reduction of area were examined. Fractography of the specimens was carried out to observe fracture mechanisms. The finite elements method has been used for modelling of deformation of the specimens. The computer simulation was performed using ABAQUS system. The computed output was compared with experimental results

Direct Laser Metal Deposition (DLMD) is a state-of-the-art manufacturing technology used to fabricate 316L stainless steel/Inconel 625 functionally graded material (FGMs) in this research. For the practical application of these materials in the industry, the effects of process parameters on the geometric characteristics and surface roughness require more investigation. This FGM was additively manufactured in five layers by changing the 316L stainless steel/Inconel 625 ratio in each layer. The effects of laser power on geometric characteristics, height stability, and surface roughness were investigated. The microstructural analysis and microhardness profiles were studied. The results show that despite the high solidification rate, the segregation of alloying elements into dendritic areas occurred. It was also found that increasing the laser power will increase the height, width, height stability, and surface roughness of the gradient walls. The maximum width and height of the deposited layers were 1.615 and 6.42 mm, respectively, at the highest laser power (280 W). At the laser power of 220 W, the least surface roughness (Ra = 105 µm) and the best height stability (0.461 mm) will be obtained. The microhardness values will differ in various sections of the gradient walls in a range of 225–277 HV.

• Integral form of laser power density was proposed to embody the process parameters of SLM. • The effects of energy density on residual stress depends on thermal cycling characteristics. • The correlation of RS patterns with thermal cycling features were demonstrated. Contradictory interpretation of the parameter dependence of residual stress in alloy parts formed through selective laser melting (SLM) were found in existing research, which is thought to be clarified in the present article. Parametrical simulations and experiments were designed and conducted firstly to concentrate on the dominant significance of the typical thermal cycling in SLM. It has been proved both by the XRD, EBSD and TEM experiments that correlation between residual stress and energy density depends on the peculiar characteristic of thermal cycling. Furthermore, the microscopic characterization accompanied with simulations of computational fluid dynamics, computational thermo-elastic-plastic mechanics and molecular dynamics reveals the effects of typical thermal cycling on the patterns of residual stress. [ABSTRACT FROM AUTHOR]

• Innovation in projectile rod structure: The article introduces a new design by applying a jacket material to small aspect ratio tungsten fibre/Zr-based Bulk Metallic Glass Composite. The jacket material enhances the dynamic strength of the rod during penetration, changes the rheological and interaction modes of the target material during penetration, reduces the resistance encountered during penetration, improves the penetrating performance of the rod, and mitigates the phenomenon of irrational penetration in small length-to-diameter ratio rod. This has significant implications for the engineering application of rod materials. • Innovation in experimental methods: Prior to this article, scholars analyzed the penetration performance of rod materials through macroscopic experimental methods based on the terminal damage morphology of target penetration results. This article uses microscopic analysis methods such as optical microscopy, SEM, and TEM to analyze the penetration performance and deformation mode of the rod from the perspective of penetration rheological mechanism. The experimental scale is smaller, and the experiment is more detailed. Provide a new research approach for subsequent similar studies. Enriched the research methods for this issue. • Innovation in theoretical analysis: Through theoretical deduction, this article analyzes the energy dissipation during the penetration process of two structural rods. This provides theoretical support for the design of rod structures in future research. To investigate the influence of a tungsten fibre/Zr-based bulk metallic glass matrix composite (WF/Zr-MG) jacketed with C45 steel on penetration performance, this paper presents a ballistic experiment on a semi-Infinite RHA target impacted by a composite structure rod consisting of 80 % volume fraction of WF/Zr-MG (with a tungsten fibre diameter of 0.3 mm) and a low-density jacketed material (C45 steel) with an impact velocity of 1700 ± 50 m/s. This composite structure rod is compared with an unjacketed WF/Zr-MG rod. Using optical metallography and electron microscopy, this study aims to provide a comprehensive microstructural overview of the penetration process, including the solid-state penetrator flow and the exchange interaction mode of rod and target materials. The penetration performance of the two structural rods is analysed through theoretical calculation. Results indicate that the jacketed structure not only provides radial and circumferential constraints for the WF/Zr-MG rod, improving its dynamic strength, but also serves as an exchange medium for the target material during the penetration process. This characteristic changes the exchange mode of the target material and affects the interface flow mechanism. The jacketed material also acts as a solid-state lubricant at the interface, reducing the resistance to the rod's penetration. The average penetration depth of the jacketed rod is 22 % higher than that of the unjacketed rod, and the unjacketed rod consumption per unit penetration depth accounts for 3.45 % of the initial kinetic energy. while jacketed rod was only 2.5 %, which has revealed the jacketed material enhances the rod's performance and provides it with self-lubricating characteristics. [ABSTRACT FROM AUTHOR]

• The crack occurred in the overheating zone of the basic material at a distance up to several hundred µm from the fusion line. • The crack was intergranular along the boundaries of the expanded grains of the prior austenite. • Metallography showed the presence of precipitates of secondary carbides located along the prior austenite grain boundaries. • The most likely cracking resulting from reheating of the joint, otherwise known as annealing or reheating cracking. The article concerns a pressure vessel operated for forty years at elevated temperature in in an ammonia production installation. During the planned control tests, unacceptable defects were detected in the circumferential welded joint of the vessel, using the ultrasonic method. In the repair process, a fragment containing a crack located in the heat-affected zone was cut out of the welded joint. The cut fragment of the joint was subjected to tests, the results of which are discussed in this article. On the basis of chemical composition, hardness, macroscopic and microscopic tests, it was determined which factors had a negative impact on the formation of the crack. The most important of them are: an increase in the hardness of the base material and grain growth in the overheating zone, as well as the formation of numerous precipitates and their segregation at grain boundaries. The reheating of the joint during its subsequent repairs should be considered a negative factor. [ABSTRACT FROM AUTHOR]

This correction notice addresses a typographical error in an article titled "Statistical Comparisons & Correlations of Thermal Analysis, Ultrasonic Velocity and Image Analysis Metallography Methods for Quantification of Ductile Iron Microstructure" published in the International Journal of Metalcasting. The correction involves a sentence on page 56, where the phrase "nodule count with nodule count" is corrected to "nodule count with nodularity." The correction provides a more accurate explanation of the reasons for the metallurgical superiority of the 'INclusionary' nodule count. The correction notice also includes a statement from the publisher, Springer Nature, emphasizing their neutrality regarding jurisdictional claims and institutional affiliations. [Extracted from the article]

New excavations at Espidej at the Kerman Province of the Halil Basin corridor in Iran offer a unique opportunity to reconsider the third millennium BC (i.e. Bronze Age) metallurgical practices related particularly to arsenical copper (Cu‐As) alloying and to explore arsenic‐bearing raw materials. This paper presents results of optical microscopy and environmental scanning electron microscopy (ESEM) on a selected group of copper‐based artefacts from Espidej. Additionally, we have benefited from synchrotron light for further investigations on a dagger sample. The scientific examinations on metal corpora adds new information regarding the microchemistry and production techniques of metals of the south‐eastern cultural zone of Iran. Synchrotron micro X‐ray diffraction (SR‐μXRD) data of the sample demonstrates traces of arsenic‐bearing minerals in the corrosion products indicative of types of ores used in alloying processes. Preliminary research on copper ores indicates possible extraction of local ore deposits that were outcropped along the south‐east Makran orogeny zone of Iran. This area is part of hydrothermal mineralization zone consisting of arsenopyrite (FeAsS), sinnerite (Cu6As4S9), bornite (Cu5FeS4) and algodonite (Cu6As). Noticeable arsenic‐bearing phases within the metallic core of the sample were frequently characterized as sinnerite and algodonite. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic 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.)

A new application of a centerless x-ray diffractometer was proposed that goes beyond residual stress measurements during the regular operation of such equipment. During depth residual stress measurement, it is possible to fit the measured interference function of the ferrite (211) with a different number of curves as a function of depth. The different curves corresponded with the appearance of ferrite fractions with different grain sizes and concentrations in ferrite, perlite, bainite, or martensite. Accordingly, different microstructures were non-destructively detected through the thickness of the carburized layer, and a good correlation was found with results from metallography and hardness testing. This novel method was validated on solid and gas carburized samples, but more work is needed to apply it to other microstructures. [ABSTRACT FROM AUTHOR]

Aluminum alloys are used as construction material for ultra-high vacuum (UHV) chambers of synchrotron radiation sources (SRS) due to UHV compatibility, high thermal conductivity and non-magnetic requirements. Aluminum alloy AA5083-H321 has been used as material of construction for UHV dipole chambers of Indus-2 SRS at RRCAT. Weld joints of UHV chambers require helium leak tightness less than 2E-10 mbar·l/s. Weld joint design and selection of right base and filler materials need special care in obtaining leak tight joints of vacuum chambers by gas tungsten arc welding (GTAW). GTAW is used in the fabrication of the present dipole chambers which are welded in lip-fillet configuration. One of the in-service dipole chambers has developed leak over time at few locations and has been repaired in-situ. This failure due to fine cracks developed in the weld region of the dipole chamber can be attributed to either material of construction or weld design. In this study, GTAW welding of similar base alloys viz. AA5083 to AA5083 with filler rod ER5183 and AA6061 to AA6061 with filler rod of ER4047 has been carried out. It reports the investigations carried out with respect to their GTA welds fabricated in two different weld joint designs. Computational studies were also carried out to obtain residual stresses in weld joints using finite element analysis (FEA). The GTA weld joints are subjected to various quality tests including helium leak test, thermal cycling and metallographic examination. Helium leak tightness (2E-10 mbar·l/s) was achieved in both the welds of AA5083 (ER5183 filler) and AA6061 (ER4047 filler), however, fine cracks are seen at the root of AA5083 welds whereas welds of AA6061 were free of such defects. Based on these investigations, weld-joint design and material of construction (including filler material) are proposed for new dipole vacuum chambers of Indus-2. [ABSTRACT FROM AUTHOR]

NEED—The effect of dimensional variability of sheet thickness (tolerance) and tool misalignment is poorly understood for the clinching process. Finite element analysis (FEA) is valuable but requires a lot of and is difficult to verify in this situation due to the asymmetrical geometry and nonlinear plasticity. OBJECTIVE—The objective of this work was to determine the effect of thickness tolerance, tool misalignment and sheet placement (top vs. bottom) in the clinching process, by use of analogue modelling with plasticine. METHOD—Experiments used a scaled-up punch and die, with plasticine as the analogue. Thickness tolerances were represented by sheet thicknesses of 11 and 7 mm, 12 and 8 mm, 8 and 12 mm and 13 and 9 mm for upper and lower sheets, respectively. Two types of lubricant were tested between sheets: glycerine and silicone oil. Angular variability was also introduced. Measured parameters were interlock (also called undercut) and neck thickness. Analogue results for deformation were compared with microscopy of metal clinching. FINDINGS—The results reveal that the multiscale analogue model is an efficient tool for studying the effect of dimensional deviation on a clinch joint. Thickness tolerance showed a critical relationship with interlock, namely a reduction to about half that of the nominal, for both maximum and least material conditions. Increased angular misalignment also reduced the interlock. Compared with glycerine, silicone oil tests showed reduced interlock, possibly the result of a lower coefficient of friction. ORIGINALITY—This work demonstrates the usefulness of analogue modelling for exploring process variability in clinching. The results also show that significant effects for sheet placement are ductility, lubricant (friction), thickness of samples and tool misalignment. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office 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.)

The 17-4PH eccentering ailll is fastened with the inner countersunk head hexagonal hole screw(17-4PH), which mainly bears shear force. During logging operation, the screw broke. In this paper, the failure analysis of the broken focuses on aspects of micro and macro morphology, hardness, metallography, inclusions, micro energy spectrum, chemical composition and artificial fracture morphology. According to the test results, the chemical composition of the screw material is qualified, while its hardness value is lower than the lower limit of the standard requirements, and there exist inclusions in the matrix. The metallographic structure is martensite and high-temperature ferrite, and the existence of ferrite destroys the continuity of the matrix. As a result, the hardness and mechanical properties decline. The fatigue fracture characteristics in the micrograph shows that the failure mechanism of the screw is fatigue fracture caused by shear stress. [ABSTRACT FROM AUTHOR]

In order to improve the accuracy of rapid evaluation of the modification effect of Al-Si alloy in front of the furnace, the relationship between resistivity change and modification level during melt solidification was experimentally studied. A melt resistivity monitoring system was designed for practical application, including a sample cup, sample cup base support, vacuum aspiration unit, constant current power supply, data acquisition module, and computer. The monitoring system was used to monitor the changes in temperature and resistivity parameters during solidification of ZL101A alloy melt treated with different amounts of Sr modifier. It was found that the curve of melt resistivity changes with temperature at the eutectic solidification stage had a plateau, and the resistivity plateau value decreased with the better alloy modification effect. Therefore, a rapid evaluation model was established of the hypoeutectic Al-Si alloy modification effect in front of the furnace based on resistivity change during melt solidification. The experimental results showed that the evaluation of the modification effect of the hypoeutectic Al-Si alloy could be completed within 3 minutes by using the monitoring system and evaluation model designed in this paper. The accuracy of the evaluation of modification level error within ± 0.5 reaches 80 % taking the metallographic observation method as the standard. [ABSTRACT FROM AUTHOR]

Liquid metal convection plays an important role in natural and technical processes. In experimental studies, an instrumentation with a sub-millimeter spatial resolution is required in an opaque fluid to resolve the flow field near the boundary layer. Using ultrasound methods, the trade-off between the frequency and imaging depth of typical laboratory experiments limits the spatial resolution. Therefore, the method of ultrasound localization microscopy (ULM) was introduced in liquid metal experiments for the first time in this study. To isolate the intrinsic scattering particles, an adaptive nonlinear beamformer was applied. As a result, an average spatial resolution of 188 μm could be achieved, which corresponded to a fraction of the ultrasound wavelength of 0.28. A convection experiment was measured using ULM. Due to the increased spatial resolution, the high-velocity gradients and the recirculation areas of a liquid metal convection experiment could be observed for the first time. The presented technique paves the way for in-depth flow studies of convective turbulent liquid metal flows that are close to the boundary layer. [ABSTRACT FROM AUTHOR]

Hammer crusher is one of the main components in the clinker cooler. A hammer crusher is a tool for crushing clinker that has cooled to reduce the size of the slag. The Hammer crusher wears out which causes its service life not to match its ideal use. The purpose of this study is to determine the cause of the failure of the hammer crusher, to know the mechanism of the failure of the hammer crusher, and to find the solution for the failure of the hammer crusher. The methodology used to solve the problem is by conducting tests where the tests carried out to analyze the hammer crusher material is composition testing carried out with the OES tool, hardness testing using the Vickers method, impact testing using the Charpy method, and metallography observed under an optical microscope. Based on testing the material composition of the hammer crusher is not up to standard. Then from the hardness test, the average value is 569.8 HVN on the hammer worn part and 481.2 HVN on the part far from worn. From the impact test, the average impact energy value in the wear section is 1.917 Joules with an average impact strength of 0.023 Joule/mm2, in areas far from wear the average impact value is 1.733 Joules with an average impact strength of 0.021 Joules. /mm2. Factors that cause the failure of the hammer crusher in the clinker cooler are the incompatibility of the material composition and the low toughness value compared to the standard, then the hammer crusher failure mechanism occurs due to wear and tear caused by differences in hardness values and changes in the mechanical properties of the material and to overcome the failure, namely by replace material according to ASTM A532 standard composition. [ABSTRACT FROM AUTHOR]

Wire feedstock laser metal deposition (WFLMD) is a metal additive manufacturing (AM) technique that has several advantages over other AM processes, most notably lower feedstock costs, higher deposition rates, and the ability to make large continuous parts. The microstructure and properties of materials produced by this new technique must be studied for comparison to other techniques. This work briefly reviews published properties of 316L stainless steel produced by other processes and compares them to experimentally determined properties of 316L samples produced with WFLMD under reduced atmospheric conditions. Relative densities from WFLMD were greater than 98% and microstructure analysis showed primarily austenite, with some ferrite and carbide phases. Electron backscatter diffraction showed the presence of tilted or twisted grain structures. Strength and hardness were comparable to or better than those resulting from other processes. Fractography indicated ductile tearing with few defects, though some defects were identified with microscopy, which can be attributed to minor contamination. [ABSTRACT FROM AUTHOR]

Despite the credit attributed to India for the early production of high carbon steel, not much is known about Indian contribution to the implementation of a pertinent fabrication technique without which this special material might have little practical value. A metallographic examination of a small iron lump and an iron sheet, both excavated from the second BC to second AD century site at Junnar in India, provided evidence that the production of high carbon steel was stimulated by a sophisticated technique practiced for the control of carbide precipitation in such a peculiar material. In addition, neutron diffraction analysis on one of the objects, the iron sheet, produced key information defining the thermo‐mechanical treatments applied. An anisotropy in the orientation of cementite grains, similar to one of those documented for the so‐called Damascus swords, was also confirmed. A detailed account of the analytical results is presented, suggesting that a proper technique for the control of microstructural evolution in high carbon steel was fully established in India much earlier than the beginning of the Damascus steel tradition, which must have been inspired by technologies long practiced in India. [ABSTRACT FROM AUTHOR]

This work evaluates the behavior of microstructure in the GMAW of 2205 duplex steels welding for offshore applications. Welding is performed with two input energy levels, 1.5 kJ/mm and 2.5 kJ/mm. Samples from welds for the metallographic analysis by Optical Microscopy of Heat Affected Zone are extracted. The ferrite fraction and austenite in the microstructure is quantified from image processing. It is concluded that the relationship of austenite/ferrite phases in the ZAC was altered, regarding the base metal, without showing significant differences depending on the input energy of the process and ZAC microstructure is constituted by a ferritic matrix with grain boundary austenite (GBA), with Witmastatten austenite (WA) and intragranular austenite (IGA). For offshore applications, it is recommended to use the input energy of 1.5 kJ/mm. [ABSTRACT FROM AUTHOR]

During color etching, the examined grain structure undergoes a continuous, cyclic color change. This phenomenon is accompanied by a continuous loss of light intensity reflected from the surface. If the etching process is not stopped in time, the surface will be over etched. As a result, the separability of the individual grains will be greatly damaged, which can lead to a significant loss of information. It was investigated how to determine the moment of over-etching for each grain. During the in-situ observation of the etching, the time at which a particle can be considered over etched was determined by measuring the luminance normalized to the initial state. [ABSTRACT FROM AUTHOR]

Duplex stainless steels offer a high strength alternative to stainless steel, while providing excellent corrosion resistance, due to their dual-phase microstructure. This microstructure can be significantly influenced during welding, thus the maximum recommended heat input is usually 2.5 kJ/mm. In this research, we inspected the high heat input (3 kJ/mm) weldability of NSSC 2120 lean duplex stainless steel, which is designed and developed specifically for this purpose. The welds were evaluated by metallographic techniques and corrosion tests. It was found the NSSC 2120 grade can be welded with high heat input without deterioration in the phase balance and microstructure. [ABSTRACT FROM AUTHOR]

Copyright of Revista Facultad de Ingeniería - UPTC is the property of Universidad Pedagogica y Tecnologica de Colombia, Facultad de Ingenieria 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.)

A long-term field study on corrosion of STK400 steel was established at Phu My port. The large steel pile, which was equivalent to real structures, was placed in all environmental zones to evaluate the overall corrosive effects of the brackish water. After 5 years, the corrosion rate over the entire length of the steel pile was measured and the rust at the boundary altitude between the zones was characterized. The corrosion rate profile shows the polarization of the entire pile length into two large anodic areas at the highest water level and submerged zones, where had high corrosion rate and pitting corrosion form. X-ray diffraction and metallographic of rust layers showed that Fe3O4 phase increased with water depth, allowing to strong diffusion of Fe2+ ion from steel substrate into the environment. The change in organism populations along water altitude in the tidal and submerged zones made the rust layers more complicated. Such distribution of polarized electrodes and composition of rust were due to the renewal of the corrosive agent by tidal cycles and organism population in water. As a result, the steel substrate in the tidal and mud zones was protected as cathodic areas. [ABSTRACT FROM AUTHOR]

Metallography is crucial for a proper assessment of material properties. It mainly involves investigating the spatial distribution of grains and the occurrence and characteristics of inclusions or precipitates. This work presents a holistic few-shot artificial intelligence model for Quantitative Metallography, including Anomaly Detection, that automatically quantifies the degree of the anomaly of impurities in alloys. We suggest the following examination process: (1) deep semantic segmentation is performed on the inclusions (based on a suitable metallographic dataset of alloys and corresponding tags of inclusions), producing inclusions masks that are saved into a separated dataset. (2) Deep image inpainting is performed to fill the removed inclusions parts, resulting in 'clean' metallographic images, which contain the background of grains. (3) Grains' boundaries are marked using deep semantic segmentation (based on another metallographic dataset of alloys), producing boundaries that are ready for further inspection on the distribution of grains' size. (4) Deep anomaly detection and pattern recognition is performed on the inclusions masks to determine spatial, shape, and area anomaly detection of the inclusions. Finally, the end-to-end model recommends an expert on areas of interest for further examination. The physical result can re-tune the model according to the specific material at hand. Although the techniques presented here were developed for metallography analysis, most of them can be generalized to a broader set of microscopy problems that require automation. All source-codes as well as the datasets that were created for this work, are publicly available at https://github.com/Scientific-Computing-Lab-NRCN/MLography. [ABSTRACT FROM AUTHOR]

Materials obtained by non-vacuum electron beam cladding of powder mixtures containing chromium, nickel and titanium onto billets from steel É76 are investigated. The structure of the claddings is studied by optical metallography and scanning and transmission electron microscopy. The chemical composition and the microhardness of the deposited layers are determined. It is shown that steel É76 acquires flaw-free layers with maximum thickness 3.5 mm and a structure represented by austenite, titanium carbonitrides and a chromium- and iron-based intermetallic phase with variable composition. Martensite regions with a width of up to 40 μm and a microhardness of up to 765 HV are detected near the interfaces. The conditions for cladding railroad frogs are determined. [ABSTRACT FROM AUTHOR]

The influences of the forging process and micro-arc oxidation (MAO) coating on the corrosion behavior of ZK60 wrought magnesium alloys exposed to salt spray and constant stress corrosion conditions were investigated. The microstructure of the ZK60 Mg alloy specimens forged under different temperatures (i.e., 250, 300, and 450 °C) was characterized using metallography, EBSD, and SEM. It was demonstrated that the ZK60 alloy forged at 300 °C (i.e., ZK60EF-300) had finer grain and uniformly distributed β-phase and, thus, better corrosion resistance than the ZK60 forged at 450 °C. At the lower forging temperature (250 °C) twins formed in the ZK60 alloy, which accelerated the corrosion of the ZK60E-250 specimen. The MAO coating provided robust corrosion protection for all the ZK60 wrought Mg alloy substrates. The salt spray corrosion test results showed that when the MAO coating broke down at certain weak sites, the corrosion performance of the coated Mg alloy was predominantly determined by the alloy substrate. The stress corrosion behaviors of the uncoated and MAO-coated ZK60 alloy specimens were also investigated under a constant load of 80 MPa in 3.5 wt.% NaCl solution. The MAO coating was found to improve the stress-corrosion resistance of the ZK60 alloy pronouncedly. [ABSTRACT FROM AUTHOR]

Nickel Aluminum Bronze (NAB) and Manganese Aluminum Bronze (MAB) are high-alloyed bronzes that are increasingly employed in several industrial sectors, mainly related to hostile environments due to their excellent properties against corrosion, cavitation, erosion and improved mechanical properties in relation to other copper-based alloys. These materials are very sensitive against thermal treatments due to a multiphase microstructure in as-cast condition. To contribute to the knowledge of the behavior of both alloys, the effect of thermal treatments on the corrosion behavior of NAB (CuAl10Fe5Ni5) and MAB (CuMn12Al8Fe4Ni2) was studied. As-cast material was subjected to various combinations of quenching and quenching and tempering at 850 °C and 600 °C. Corrosion testing was carried out using simulated sea and fresh water. The microstructures of the as-cast and heat-treated samples were characterized by metallography using two chemical agents with FeCl3 and NH4OH solutions and examination by optical and scanning electron microscopy. The major effect of thermal treatments on corrosion was found in influencing the amount and distribution of β-phase, which is prone to selective corrosion in both electrolytes. [ABSTRACT FROM AUTHOR]

Reinforcing bars sometimes need to be bent during the construction of reinforced concrete structures and these bent portions develop very high levels of plastic strains. This work presents a comprehensive study on the magnitude of tensile and compressive strains induced during bending, and the corrosion behavior of bent bars using electrochemical and immersion tests carried out in chloride-contaminated simulated concrete pore solution. A detailed study of the microstructural changes in bar due to bending and their relationship with corrosion is also presented. Results indicate higher corrosion tendency of the strained location as compared to the unstrained location. The corrosion rate increases with the angle of the bend and can be principally attributed to changes in surface condition, microstructure and accumulation of residual tensile and compressive strains. [ABSTRACT FROM AUTHOR]

The goal of using nondestructive evaluation (NDE) in conjunction with failure analysis is to obtain the most comprehensive set of data in order to characterize the details of the damage and determine the factors that allowed the damage to occur. The NDE results can be used to determine optimal areas upon which to focus for sectioning and metallography in order to further investigate the condition of the component. This article provides information on the inspection method available for failure analysis, including standard methods such as visual testing, penetrant testing, and magnetic particle testing. It covers the effects of various factors on the properties of the part that may impact failure analysis, describes the characterization of damage modes and crack sizes, and finally discusses the processes involved in application of NDE results to failure analysis. [ABSTRACT FROM AUTHOR]

There have been few attempts to conduct highly controlled laboratory experiments to isolate how wear propagates on metal artefacts with differing metallurgy during simulated use. This reflects a lack of appreciation for the underlying structure of materials within the production of reference datasets for metalwork wear analysis. Here, we present the use of a drop tower (Instron CEAST 9350) to reconstruct use on replica Bronze Age palstave axes with archaeologically relevant microstructures. The development, form, and properties of surface wear at the cutting edge were sequentially analysed by low‐power microscopy (digital), high‐power microscopy (Scanning Electron Microscope), and microhardness indentation. Major deformations of the blade were documented by photography. This intensive approach reveals the impact of abrasive wear associated with sharpening and use, as well as the frequency and morphology of larger deformations generated by repeated impact—all of which, we demonstrate, can be overtly modified by subtle differences in metallurgy. [ABSTRACT FROM AUTHOR]

Image segmentation is an important issue in many industrial processes, with high potential to enhance the manufacturing process derived from raw material imaging. For example, metal phases contained in microstructures yield information on the physical properties of the steel. Existing prior literature has been devoted to develop specific computer vision techniques able to tackle a single problem involving a particular type of metallographic image. However, the field lacks a comprehensive tutorial on the different types of techniques, methodologies, their generalizations and the algorithms that can be applied in each scenario. This paper aims to fill this gap. First, the typologies of computer vision techniques to perform the segmentation of metallographic images are reviewed and categorized in a taxonomy. Second, the potential utilization of pixel similarity is discussed by introducing novel deep learning-based ensemble techniques that exploit this information. Third, a thorough comparison of the reviewed techniques is carried out in two openly available real-world datasets, one of them being a newly published dataset directly provided by ArcelorMittal, which opens up the discussion on the strengths and weaknesses of each technique and the appropriate application framework for each one. Finally, the open challenges in the topic are discussed, aiming to provide guidance in future research to cover the existing gaps. [Display omitted] • We create a metallography dataset from additive manufacturing of steels (MetalDAM). • We provide an updated taxonomy of segmentation methods. • We propose a new DL-based ensemble specialized in the semantic segmentation task. • We compare state-of-the-art models and the new ensembles with UHCS and MetalDAM. • We present a thorough analysis of the current difficulties and challenges. [ABSTRACT FROM AUTHOR]

Industries demand that their products are high quality with the least number of defects due to the rapid improvement in manufacturing technology. Quality is a critical criterion for evaluation in manufacturing firms. The production of a final product that can meet customer requirements is essential in a sustainable supply chain system to reduce costs, increase productivity and provide high-quality products. The aim of the study is to identify the root cause of defects emerging in the production process of prestressed railway concrete sleepers. Ishikawa diagram and Pareto analysis were used to identify the root cause. The results showed that the cause of the faulty concrete sleeper is the breaking of the bolts, which are supplied by the external provider. Since the supplier refused to accept the complaint, chemical analysis and measuring of hardness and microhardness of bolts were realized. It showed that the hardness of the bolts does not achieve the values, which should be achieved after the declared heat-treatment. As a corrective action, the input control of bolts hardness was proposed as well as establishing the team cooperating with the supplier to improve the heat treatment process, which will be the objective of further study. [ABSTRACT FROM AUTHOR]

The production of aluminum metal matrix composites (AMMCs) has been a great challenge for commercial sectors and the research fraternity. Over the past few decades, many modifications and hybrid techniques have been designed and developed by the researchers to address the manufacturing issues and reduce the production cost in developing AMMCs. In this regard, there is a need to address fundamental issues such as wettability and uniform distribution of particles across the matrix. Due to the poor mixing of particles, the materials' hardness, strength, and wear properties are affected. In the present research, aluminum-titanium diboride metal matrix composite (Al-TiB2 MMC) has been synthesized by developing a novel hybrid liquid processing technique. The performance efficacy of the novel hybrid experiment setup has been determined through the computational fluid dynamics (CFD) approach. Metallography has been done to demonstrate the uniformity of TiB2 phase in aluminum. Mechanical and wear behavior of the Al-TiB2 MMC have been subsequently assessed and compared with conventional processing technique. The results obtained in the current study are promising and demonstrate the potential benefits of the novel hybrid liquid processing system from an industrial standpoint. [ABSTRACT FROM AUTHOR]

Hiberno-Norse levels excavated in the cities of Dublin and Waterford produced a wealth of ferrous and non-ferrous metal artefacts. Metallographic examinations were conducted on a group of 37 tanged, single-edged knives from different Dublin sites, dating from the late tenth–late eleventh centuries AD, and on four from contexts in Waterford covering the period c. AD 1050–1100. The assemblage exhibited a range of techniques for fabricating cutting edges, ranging from forging from low carbon iron to sophisticated multi-piece construction and the use of heat-treated steel. This paper is a summary report on the results. [ABSTRACT FROM AUTHOR]

The mats, after the casting process present an austenitic structure with harmful carbides on the grain edges, which must be eliminated. The objective of this research was the study of heat treatments that guarantee the desired structure and resistance parameters for the correct commissioning of mats manufactured in Cuba for armored vehicles. Prototype specimens foundry workshops were elaborated, they were subjected to different tempering regimes at 1050 °C, with a residence time at this temperature of 30 and 60 min, in addition they were tempered at 200, 400 and 600 °C respectively with a residence time of 120 min. Chemical composition, metallography, hardness, grain size, scanning electron microscopy (SEM) and x-ray spectrometry (EDS) were studied. After the casting process, a quench in water with low tempering at 200 °C is proposed, guaranteeing the relief of internal stresses and an austenitic matrix free of carbides. In addition, statistical analysis was developed, which has made it possible to produce high quality mats, substituting imports. [ABSTRACT FROM AUTHOR]

The paper presents the results of structural investigations of a laser-welded layer in the Inconel 625 and Stellite 6 alloy matrix with the addition of WC. The tests involved the use of on plates made of low-alloy steel S355J2C+N. The filler materials used in the tests were nickelbased (Inconel 625) or co-balt-based powders (Stellite 6) having various contents (0-25%) of spherical tung-sten carbide (WC) used as the reinforcing phase. The granularity of the powders was re-stricted within the range of 45 µm to 90 µm. The cladding tests involved making multi-layer overlay welds. Next, non-destructive (VT and PT) and destructive (macro, hardness) tests were carried out. The macroscopic metallographic tests revealed that the three-layer Inconel 625- based overlay welds (with a WC content of up to 15%) had the correct shape and were characterized by full fusion into the base material, ensuring the continuity of the overlay weld.In the case of the Stellite 6-based overlay welds containing 10% of WC, it was possible to observe a throughcrack of the overlay welds. The crack was formed in the first layer (as a result of stresses during the solidification of the liquid metal) and developed during the deposition of subsequent layers. The macrostructural tests were supplemented with microstructural observations and microanalysis of the chemical composition (EDS). The above-named tests revealed the good stirring of alloying elements in the overlay weld, indicating the high homogeneity of the overlay weld.The hardness obtained on the surface of the padding weld was 600 HV1. [ABSTRACT FROM AUTHOR]

This paper presents analysis of the influence of selected electrical parameters of hollowing on the state of the surface layer after electrical discharge machining (EDM). Namely, paper focuses on the analysis of the EDM cutting process, in terms of the influence of individual parameters on the number of occurrences and sizes of erosion craters on the machined surface. The basic parameters include electrical pulse discharge time, electrical discharge pause time, voltage, current amplitude and servo voltage. The initial values of the mentioned parameters were selected based on technology tables provided by the machine manufacturer and on the basis of own empirical tests. The tests were carried out according to static determined poliselective experimental plan (Hartley plan). Analysis of the machined surface was carried out using a scanning microscope (SEM) and an optical microscope. Quantitative metallographic analysis was used to determine the stereological features of erosion craters occurring on the surface of the machined material. The results were illustrated by means of three-dimensional graphs. The presented studies show a significant effect of electrical parameters of EDM on the quality of the machined surface, i.e. the number of occurrences and diameter of erosion craters. The research presents an approach based on mathematical modelling of electrical discharge machining. This approach can form the basis for developing methods of modeling technological processes and optimizing their parameters. [ABSTRACT FROM AUTHOR]