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The high-temperature shaping of steels is accompanied by the formation of surface scales composed of oxide layers. However, the oxidation kinetics and morphology of these scales remain poorly understood. This study analyses the formation of oxide layers on AISI 4140 steel at varying oxidation times (20, 40 and 60 min) at 1000 °C. The analysis revealed the presence of hematite, magnetite, and transformed wustite in the oxide layers, along with clusters of alloying element oxides, predominantly chromium and iron oxide (FeCr2O4). There was a direct correlation between the duration of the oxidation process and the thickness of the scale and the number of defects observed in the material. The coating layer of alloying element oxides demonstrated insufficient adhesion to the steel substrate. Similarly, the oxides of alloying elements within this layer exhibited low cohesion among themselves. The alloying elements are present in all oxide layers, but in greater quantity in the layer in contact with the steel substrate, where a reduction in their concentrations was observed over time. This indicates that the alloying elements tend to disperse as the thickness of the alloying element oxide layer increases over time. [ABSTRACT FROM AUTHOR]

SiMo ductile irons, typical heat-resistant materials, are subjected to varied wear environments during operation in high-temperature applications. SiMo ductile iron castings of different thicknesses were cast in investment and greensand molds, achieving a wide range of cooling rates. The present work aims to investigate the effect of the cooling rate and alloying elements (Cr, V, and Ni) on the microstructure and the abrasive wear behavior of these grades of SiMo ductile iron at high-temperature 700 °C under different loads. Thermodynamic calculations were used to propose the phase diagrams, critical transformation temperatures, and phase volume fractions in all SiMo alloys by using the Thermo-Calc software then verified by and Differential Scanning Calorimetry (DSC). The microstructure of unalloyed SiMo ductile cast iron consists of graphite nodules and carbides embedded in the precipitates at the grain boundary regions in a ferrite matrix. The alloyed SiMo microstructure contains nodular graphite and the carbides promoted by the alloying elements (Cr and V). The alloyed SiMo alloys exhibit higher wear resistance than unalloyed ones. These wear results support that the microstructure plays a chief role in wear loss. The combination of M6C, VC, and M7C3 carbides embedded in a ferrite-pearlite matrix (alloyed SiMo) seems to be more resistant to wear than the ferritic matrix with lamellar pearlite and eutectic M6C carbides (unalloyed SiMo). [ABSTRACT FROM AUTHOR]

The interface connects the reinforced phase and the matrix of materials, with its microstructure and interfacial configurations directly impacting the overall performance of composites. In this study, utilizing seven atomic layers of Mg(0001) and Ti(0001) surface slab models, four different Mg(0001)/Ti(0001) interfaces with varying atomic stacking configurations were constructed. The calculated interface adhesion energy and electronic bonding information of the Mg(0001)/Ti(0001) interface reveal that the HCP2 interface configuration exhibits the best stability. Moreover, Si, Ca, Sc, V, Cr, Mn, Fe, Cu, Zn, Y, Zr, Nb, Mo, Sn, La, Ce, Nd, and Gd elements are introduced into the Mg/Ti interface layer or interfacial sublayer of the HCP2 configurations, and their interfacial segregation behavior is investigated systematically. The results indicate that Gd atom doping in the Mg(0001)/Ti(0001) interface exhibits the smallest heat of segregation, with a value of −5.83 eV. However, Ca and La atom doping in the Mg(0001)/Ti(0001) interface show larger heat of segregation, with values of 0.84 and 0.63 eV, respectively. This implies that the Gd atom exhibits a higher propensity to segregate at the interface, whereas the Ca and La atoms are less inclined to segregate. Moreover, the electronic density is thoroughly analyzed to elucidate the interfacial segregation behavior. The research findings presented in this paper offer valuable guidance and insights for designing the composition of magnesium-based composites. [ABSTRACT FROM AUTHOR]

The creep properties of fully lamellar γ/α2 titanium aluminides can be significantly improved by alloying with Nb, Ta or Zr. While the influence of these alloying elements on the γ-phase has already been examined, their diffusivity and strengthening properties in the α2-phase are still lacking. In order to study the effect of Nb, Ta and Zr in α2-Ti3Al, the alloys Ti-33Al, Ti-33Al-5Nb, Ti-33Al-5Ta and Ti-33Al-5Zr were investigated using a diffusion couple approach and strain rate jump tests. The results show that Zr diffuses the fastest, followed by Nb and Ta. Furthermore, these alloying elements also increase the strength compared to a binary Ti-33Al alloy, from which Zr leads to the highest strength increase followed by Ta and Nb. The lower diffusivity of Ta becomes increasingly important at higher temperatures and lower strain rates resulting in a higher strengthening potential than Nb and Zr under such conditions. [ABSTRACT FROM AUTHOR]

Using the tin alloy module in the material phase diagram and thermodynamic simulation software JMatPro, the phase compositions of different components of Sn-Bi-Pb low melting point alloys with the same Sn content were simulated based on the phase diagrams of Sn-Bi, Sn-Pb, and Pb-Bi binary alloys, and the influence of alloying element content on the melting characteristics of the alloys was investigated, which was used for the optimization of the components and the obtaining of low melting point alloys with excellent melting characteristics. The microstructure and melting characteristics of the optimized alloys were characterized by Scanning electron microscope (SEM), Thermogravimetry Analysis-Differential Scanning Calorimetry (TG-DSC), X-ray diffractometer (XRD), etc., and the influence of phase content on the mechanical properties was investigated. The results show that the Sn-Bi-Pb alloy possesses Sn-(Bi, Pb) phase, Bi-(Pb) phase and Pb7Bi3 intermetallic compound phase, and the simultaneous increase of the Bi element and decrease of the Pb element content to the Sn-Bi-Pb alloy obviously improves its tensile strength, but the elongation rate shows a decreasing trend, among which Sn50Bi30Pb has the optimal comprehensive performance, with a tensile strength of 38.60 MPa, an elongation of 61.13%, and a melting range of 94.0℃~100.6℃. [ABSTRACT FROM AUTHOR]

In this work, thermodynamic calculation on glass forming ability of Mo-Co-B system was carried out based on a combination method of improved Miedema's model and Ouyang's model, and the influence of refractory and transition metals on glass forming ability of Mo-Co-B system was discussed. It is found that, Mo-Co-B system has high glass forming ability and amorphous alloys with composition close to Mo-B system have good thermal stability. Among Mo/W/Nb/Ta-Co-B systems, Nb and Ta-containing systems have high glass forming ability over a wide composition range, while W-containing system exhibits low glass forming ability. Among Mo-Co/Fe/Ni-B systems, Ni-containing system has high glass forming ability over a wide composition range, especially for Mo-rich corner and Mo-Ni edge, while Fe-containing system exhibits low glass forming ability. Comparison between the systems doping with refractory and transition metals indicates that, doping with refractory metals can better improve the glass forming ability of Mo-Co-B system. [ABSTRACT FROM AUTHOR]

The continuous industrial development that occurs worldwide generates the need to develop new materials with increasingly higher functional properties. This need also applies to the basic material for electricity purposes, which is copper. In this article, we carry out studies on the influence of various alloying elements such as Mg, In, Si, Nb, Hf, Sb, Ni, Al, Fe, Zr, Cr, Zn, P, Ag, Sc, Pb, Sn, Co, Ti, Mn, Te and Bi on the electrical and mechanical properties of ETP-grade copper. The research involves producing copper alloys using the gravity die casting method with alloy additions of 0.1 wt.%, 0.3 wt.% and 0.5 wt.%. All resulting materials are cold-worked to produce wires, which are subsequently homogenized and annealed. The materials produced in this manner undergo testing to determine their specific electrical conductivity, tensile strength, yield strength, elongation and Vickers hardness (HV10 scale). [ABSTRACT FROM AUTHOR]

Zirconium (Zr)-based alloys are widely used as fuel cladding material for light water reactors. Under a loss-of-coolant accident (LOCA) condition, the oxidation of fuel cladding by high-temperature steam induces the degradation of mechanical properties of the cladding and would affect the integrity of fuel rods and/or assemblies, etc., during LOCA. In this study, the distribution of the elements (zirconium, oxygen, tin, iron and chromium) in Zircaloy-4 cladding specimens oxidized in the temperature range of ~ 1350– ~ 1700 K in steam was analyzed along the radial direction of the specimens by using SEM/EPMA, and the cause of element distribution in the specimens was discussed in consideration of the morphology of precipitates in the specimens and hypothesized phase diagrams related to the elements contained in the specimens. The form of the particles precipitated and the comparison between SEM/EPMA results and hypothesized phase diagrams of Zr–Sn–O system suggested that the liquefaction of tin-rich material and/or Zr–(Fe,Cr) compounds occurred during the oxidation test. The results obtained indicate that Zircaloy-4 cladding tubes would start melting at the melting point of tin-oxide and the eutectic point of Zr-(Fe,Cr) compounds, which is much lower than the melting point of Zr, α-Zr(O), or zirconium oxide (ZrO2). [ABSTRACT FROM AUTHOR]

High-manganese austenitic steel represents an innovative variety of low-temperature steel used in the construction of liquefied natural gas (LNG) storage tanks. This steel boasts remarkable characteristics such as exceptional plasticity, superior toughness at cryogenic temperatures, and robust fatigue resistance, all while providing significant cost benefits. By utilizing high-manganese steel, the material manufacturing costs can be considerably lowered, simultaneously ensuring the long-term stability and safety of LNG storage tanks. The alloying design is pivotal in attaining superior performance in high-manganese steel. Choosing the right chemical components to control the stacked fault energy (SFE) of high-manganese steel and fine-tuning its structure can further improve the balance between strength and plasticity. Summarizing the advancements in alloying design for high-manganese steel is of great importance, as it offers a foundational dataset for correlating the chemical composition with the performance. Therefore, this paper outlines the deformation mechanisms and the principles of low-temperature brittleness in high-manganese austenitic steel, and from this foundation, it explicates the precise functions of alloying elements within it. This aims to provide a reference for future alloying designs and the industrial deployment of high-manganese steel in LNG storage tanks. [ABSTRACT FROM AUTHOR]

The objective of the current work is to establish the conventional mechanisms of grain refining, and the effect of the refiner-modifier interaction in Al-based alloys on the resultant grain refining obtained. The different castings were carried out in preheated metallic molds with solidification rates of around 0.15 °C/s and 7 °C/s. As the nucleation sites (Al3Ti) change in composition depending on the percentage of Si in the alloy, the term “poisoning” frequently used to explain the loss or weakening of the power of the refiner, is misused. Addition of L12 metals e.g., Zr and Sc would contribute to constitutional undercooling, restricting the coarsening of α-Al grains as well as act as suitable sites for heterogeneous nucleation. The use of transition or ultra pure (99.99) metals would increase the degree of undercooling as well as nucleation of new grains due to precipitation of the second phase leading to the formation of a heterogeneous grain distribution. Thus, grain refining of binary alloys - partially or fully, may not be produced only through constitutional undercooling. It is suggested that, the use of 0.18%Sc has more-or-less the same grain refining efficiency of 0.15%Ti added in the form of Al–Ti–B master alloy i.e., reduction in the grain size by about 85% and an increase in the alloy strength by about 30%. For a given solidification rate, there is a grain refining threshold beyond which no further refining can be achieved. Apparently grain refining mechanisms are independent of solidification rate, only the extent of refining.

Based on the five main activation mechanisms, this study explored the potential activating elements in Al-based sacrificial anodes (SAs) combining electrochemical experiments and theoretical calculation. Mn, Y, Zr, Nb, and Ta, aligning with several activation mechanisms, are expected to be the potential activating elements besides the acknowledged activating elements (In, Sn, Ga, Zn, Bi). In addition, the negative shift of potential effect of In to Al matrix is denied both experimentally and theoretically. This study will contribute to establish a comprehensive understanding for the development of Al SAs.

Low-alloy wear-resistant steel often requires the addition of trace alloy elements to enhance its performance while also considering the cost-effectiveness of production. In order to comparatively analyze the strengthening mechanisms of Mo and Cr elements and further explore economically feasible production processes, we designed two types of low-alloy wear-resistant steels, based on C-Mn series wear-resistant steels, with individually added Mo and Cr elements, comparing and investigating the roles of the alloying elements Mo and Cr in low-alloy wear-resistant steels. Utilizing JMatPro software to calculate Continuous Cooling Transformation (CCT) curves, conducting thermal simulation quenching experiments using a Gleeble-3800 thermal simulator, and employing equipment such as a metallographic microscope, transmission electron microscope, and tensile testing machine, this study comparatively investigated the influence of Mo and Cr on the microstructural transformation and mechanical properties of low-alloy wear-resistant steels under different cooling rates. The results indicate that the addition of the Mo element in low-alloy wear-resistant steel can effectively suppress the transformation of ferrite and pearlite, reduce the martensitic transformation temperature, and lower the critical cooling rate for complete martensitic transformation, thereby promoting martensitic transformation. Adding Cr elements can reduce the austenite transformation zone, decrease the rate of austenite formation, and promote the occurrence of low-temperature phase transformation. Additionally, Mo has a better effect on improving the toughness of low-temperature impact, and Cr has a more significant improvement in strength and hardness. The critical cooling rates of C-Mn-Mo steel and C-Mn-Cr steel for complete martensitic transition are 13 °C/s and 24 °C/s, respectively. With the increase in the cooling rate, the martensitic tissues of the two experimental steels gradually refined, and the characteristics of the slats gradually appeared. In comparison, the C-Mn-Mo steel displays a higher dislocation density, accompanied by dislocation entanglement phenomena, and contains a small amount of residual austenite, while granular ε-carbides are clearly precipitated in the C-Mn-Cr steel. The C-Mn-Mo steel achieves its best performance at a cooling rate of 25 °C/s, whereas the C-Mn-Cr steel only needs to increase the cooling rate to 35 °C/s to attain a similar comprehensive performance to the C-Mn-Mo steel. [ABSTRACT FROM AUTHOR]

Altering the content of an alloying element in alloy materials will inevitably affect the content of other elements, while the effect is frequently disregarded, leading to subsequent negligence of the common influence on the physical properties of alloys. Therefore, the correlation between alloying elements and physical properties has not been adequately addressed in the existing studies. In response to this problem, the present study focuses on the Al10Ti15Nix1Crx2Cox3 alloys and investigates the competitive interplay among Ni, Cr, and Co elements in the formation of physical properties through a single-element (SE) analysis and a multi-element (ME) analysis based on the first principles calculations and the partial least squares (PLS) regression. The values of C11 and C44 generally increase with the incorporation of Ni or Cr content in light of SE analysis, which is contrary to the inclination of ME analysis in predicting the impact of Ni and Cr elements, and the Ni element demonstrates a pronounced negative competitive ability. The overall competitive relationship among the three alloying elements suggests that increasing the content of Ni and Cr does not contribute to enhancing the elastic constants of alloys, and the phenomenon is also observed in the analysis of elastic moduli. The reason is that the SE analysis fails to account for the aforementioned common influence of multiple alloying elements on the physical properties of alloys. Therefore, the integration of SE analysis and ME analysis is more advantageous in elucidating the hidden competitive mechanism among multiple alloying elements, and offering a more robust theoretical framework for the design of alloy materials. [ABSTRACT FROM AUTHOR]

In various industrial fields, where the material wear is a prevalent stress, the microstructure of wear-resistant materials plays a very important role. The operational behavior of these materials differs depending on whether the microstructure consists of an austenitic or martensitic matrix. Moreover, the type, shape, and morphology of the secondary carbides produced by the heat treatment have a significant effect on the wear resistance of the material. This work investigates the effect of manganese and molybdenum on the microstructure type, the secondary precipitation, the thermal behavior, the microhardness, and the wear resistance of high chromium cast iron balls, used for raw material grinding. Basic and alloyed cast iron samples were processed in an induction furnace and characterized by spectroscopic, optical, and SEM microscopy, XRD, and DSC techniques. The secondary precipitation grain surface was measured using the ImageJ software. Microhardness and wear tests were considered to check the sample abrasion and friction resistance. The obtained results show the effect of manganese and molybdenum on the microstructural and wear properties of the cast iron. Compared to the basic cast iron, the addition of 3% of manganese favorably affects the secondary precipitation by inducing dense precipitation of carbides with polygonal morphology. On the other hand, the effect of the addition of manganese and molybdenum was reduced by a factor of six, resulting in a lower proportion of secondary carbides but better wear properties. The recorded thermograms show that molybdenum shifts the eutectic transition peak to higher temperatures compared to the manganese effect. [ABSTRACT FROM AUTHOR]

The present study focuses on the dry and wet end milling of three distinct Aluminum 7075 alloys: A7075, A7075–Sc (with a 0.18% Sc addition), and A7075–Li–Sc (containing 2.2% Li and 0.18% Sc additions). The main objective is to explore how cutting parameters (cutting speed and feed rate), heat treatment, alloy composition, and cooling methods influence A lcutting force. In the initial phase of the investigation, all three alloys underwent heat treatment. Subsequently, the machining process centered on the softest and hardest conditions, aiming at analyzing the impact of hardness on machinability behavior of the three studied alloys, using the same milling tool and a consistent depth of cut under both dry and wet conditions. The investigations also highlight the role of Li and Sc additions on the quality of surface finish, as well as burr and chip formation. In total, a sum of 108 operations have been performed on the present alloys. [ABSTRACT FROM AUTHOR]

The high-temperature shaping of steels is accompanied by the formation of surface scales composed of oxide layers. However, the oxidation kinetics and morphology of these scales remain poorly understood. This study analyses the formation of oxide layers on AISI 4140 steel at varying oxidation times (20, 40 and 60 min) at 1000 °C. The analysis revealed the presence of hematite, magnetite, and transformed wustite in the oxide layers, along with clusters of alloying element oxides, predominantly chromium and iron oxide (FeCr2O4). There was a direct correlation between the duration of the oxidation process and the thickness of the scale and the number of defects observed in the material. The coating layer of alloying element oxides demonstrated insufficient adhesion to the steel substrate. Similarly, the oxides of alloying elements within this layer exhibited low cohesion among themselves. The alloying elements are present in all oxide layers, but in greater quantity in the layer in contact with the steel substrate, where a reduction in their concentrations was observed over time. This indicates that the alloying elements tend to disperse as the thickness of the alloying element oxide layer increases over time.

In high-speed steel, carbides are essential phase constituents, which have a direct impact on engineering performance and qualities of high-speed steel. The formation, morphology, and distribution of carbides are dictated by alloying elements. In this paper, various types of carbides in high-speed steel are presented. The effects of different alloying elements such as C, W, Mo, Cr, and V on the formation of carbides in high-speed steel are discussed. Research progresses on carbide improvement by microalloying elements such as N, B, Mg, and rare earth (RE) elements are reviewed. It is reported that Cr promotes the precipitation of M2C, N enhances the formation of fibrous M2C, Mg effectively shatters the large-size carbide grid, Nb refines granular carbide MC, and rare earth elements encourage the formation of M6C, resulting in irregular M2C lamellae. The incorporation of microalloying elements improves the distribution and size of carbides and also refines the solidification structure of high-speed steel. [ABSTRACT FROM AUTHOR]

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In this study, metal disks with different chemical composition (two Ag-based alloys and three Cu-based alloys) were buried in the soil of coastal archaeological sites for a period of 15 years. The aim was to naturally induce the growth of corrosion patinas to obtain a deeper insight into the role of alloying elements in the formation of the patinas and into the degradation mechanisms occurring in the very early stages of burial. To reach the aim, the morphological, compositional and structural features of the patinas grown over 15 years were extensively characterized by optical microscopy, field emission scanning electron microscopy coupled with energy dispersive spectrometry, X-ray diffraction and micro-Raman spectroscopy. Results showed that the Cu amount in Ag-based alloys strongly affected the final appearance, as well as the composition and structure of the patinas. Corrosion mechanisms typical of archaeological finds, such as the selective dissolution of Cu, Pb and Zn and internal oxidation of Sn, occurred in the Cu-based alloys, even if areas enriched in Zn and Pb compounds were also detected and attributed to an early stage of degradation. In addition, some unusual and rare compounds were detected in the patinas developed on the Cu-based disks. [ABSTRACT FROM AUTHOR]

Atomistic simulations on the creep of a nickel-based single-crystal superalloy are performed for examining whether the so-called rhenium effect can be tuned by changing the spatial distribution of rhenium in the nickel matrix phase. Results show that Rhenium dopants at {100} phase interfaces facilitate mobile partial dislocations, which intensify the creep, leading to a larger creep strain than that of a pure Ni/Ni3Al system containing no alloying dopants. If all the Re dopants in the matrix phase are far away from phase interfaces, a conventional retarding effect of Re can be observed. The current study implies a tunable Re effect on creep via dislocation triggering at the phase interfaces. [ABSTRACT FROM AUTHOR]

The present paper discusses about a new method developed for determining the quality of BWR and PHWR core components with respect to chemistry viz; determination of alloying elements as well as impurities using Radio Frequency Glow Discharge Optical Emission Spectrometer (RF GD-OES). Various experimental parameters of Glow discharge plasma such as forward power, Argon gas pressure inside plasma chamber, pre-integration time and integration time have been optimized using "Single parameter alternative method". The method has been validated using Certified Reference Materials (CRMs) and also by comparing with other techniques such as AAS and ICP-AES using statistical tests like F-test & t-test. [ABSTRACT FROM AUTHOR]

Among different metals steel can be easily welded and welded steel has required strength, good ductility and sufficient resistance to general corrosion media. Since steel welding is being used in all types of fabrication industries, the mechanism of steel welding has been explored for different types of steel along with its multiple applications. [ABSTRACT FROM AUTHOR]

TiAl alloys represent a promising potential for use in many fields including automotive, aerospace and marine industries. Therefore, it can be considered important to investigate the ability of these alloys to withstand such harsh environments. To this intended, the following study attempted to determine the electrochemical properties of Ti–48Al–2Mo–2(Cr,Mn) (at %) alloys in 3.5 wt % NaCl solution. The results of potentiodynamic polarization experiment revealed that Mo addition can enhance the corrosion resistance of the alloys, especially the Ti–48Al–2Cr alloy. Ti48Al–2Cr–2Mo was found to have the lowest corrosion rate value of 0.1153 mm/year, whereas Ti48Al–2Mn was found to have the highest corrosion rate value of 0.3952 mm/yr. The polarization resistance (Rp) of the alloys changes from 1.33 to 5.54 kΩ cm2 depending on alloyed compositions. The electrochemical impedance spectroscopy (EIS) results confirmed that the corrosion behavior can be tailored through Mo addition. Accordingly, the best corrosion resistance belongs to the Ti48Al–2Cr–2Mo alloy, which presents the highest impedance value of 4.98 × 103 Ω. The surface morphologies of corroded alloys exhibited the pitting corrosion characteristics after the polarization experiments in 3.5 wt % NaCl solution. The number density of corrosion pits was significantly higher on the surfaces of the Ti48Al–2Mn and Ti48Al–2Mn–2Mo alloys. The enhanced corrosion resistance of Ti48Al–2Cr–2Mo alloy to NaCl solution is believed to be associated with the coupled positive effect of Cr and Mo in forming a surface film with a good protective ability. In addition, Ti48Al–2Cr–2Mo exhibited high resistance to NaCl solution at a level, which can be considered an optimum material for fabricating parts that serve in the marine environment. [ABSTRACT FROM AUTHOR]

The object of research in this work is the processes of forming the microstructure and mechanical properties of heat-resistant steels depending on their chemical composition. The microstructure and high-temperature mechanical properties of austenitic heat-resistant chrome-nickel steels of the proposed chemical composition were investigated in the work. The microstructure study determined the grain size and topography of inclusions in steels. Based on the results of mechanical tests, a multifactorial experiment was planned, which made it possible to establish the relationship between the mechanical properties of steels with alloying elements selected as factors. The obtained regression equations were used to estimate the quantitative influence of each alloying element on the corresponding mechanical properties. Analysis of the results of the experiment made it possible to determine the optimal chemical composition of steel for gas turbine engines used in the aerospace industry, as well as in the metallurgy of titanium production. It is shown that the state of solid solution and heat-resistant niobium and molybdenum carbides (chromium carbides dissolve at a temperature of 950 °C) are an important factor that significantly affects the structure, mechanical, and service properties of heat-resistant steel. The austenite structure is provided by the required amount of nickel. The resulting indicators of heat resistance of steels of different compositions, tested at temperatures of 850 °C, 950 °C, and 1050 °C, proved the superiority of steel with a higher content of carbon and chromium and a lower content of nickel. The mechanism of steel strengthening and the influence of alloying with carbon, chromium, and nickel on it have been determined. The optimal chemical composition of heat-resistant steel on an iron-nickel basis for operation at a temperature of 950 °C has been established. [ABSTRACT FROM AUTHOR]

In the upcoming years, a reduction in the use of critical elements, such as Ni and Cu, with unstable prices and high demand from the electromobility sector will become increasingly important for the PM-industry. Cr-alloyed sintered steels offer attractive properties at a moderate cost, but so far mostly Cr-prealloyed grades have been used. This work analyses the microstructural homogenisation process when Cr is introduced as admixed elemental powder. It is shown how – due to its high carbon affinity – Cr particles act as 'internal carbon-getters'. There is an intermediate 'heterogenization' of the microstructure, i.e. the iron matrix is decarburised due to the formation of (Cr, Fe)-carbides. Final homogenisation depends on the formation of a transient liquid phase through the eutectic reaction between carbides and the iron matrix. Thus, the microstructure is not only sensitive to aspects such as sintering temperature or Cr-particle size but also to the heating rate and small variations in nominal carbon. [ABSTRACT FROM AUTHOR]

The wettability and reactivity of Al alloys and B4C are of vital importance in the production of B4C-reinforced Al-matrix composites. However, previous research has primarily focused on pure Al/B4C systems, with little focus on alloying elements. In this paper, we investigated the influence of Si, Ti and Cu as alloying elements on the wettability and interfacial reactivity of an Al/B4C system using improved sessile drop methods. The B4C substrate was not wetted by molten Al at 700−1000 °C, with initial contact angles higher than 100°. However, rapid spreading was observed in the initial stages due to the formation of Al3BC and Al4C3. Si had a noticeable effect on the interfacial wettability only at levels of 15 wt% or above, with the interfacial products changing from Al3BC and AlB2 to SiC-dominated phases. The addition of Ti to Al led to the formation of TiB2-dominated interfacial products, which replaced the Al3BC and AlB2 phases, with the spreading kinetics mainly controlled by interfacial reactions in the early stages and the diffusion of Ti from the bulk of the drop to the triple line in the later stages. The addition of Cu had a negligible effect on the wettability but slightly weakened the formation of AlB2 by promoting substrate dissolution.

The interface connects the reinforced phase and the matrix of materials, with its microstructure and interfacial configurations directly impacting the overall performance of composites. In this study, utilizing seven atomic layers of Mg(0001) and Ti(0001) surface slab models, four different Mg(0001)/Ti(0001) interfaces with varying atomic stacking configurations were constructed. The calculated interface adhesion energy and electronic bonding information of the Mg(0001)/Ti(0001) interface reveal that the HCP2 interface configuration exhibits the best stability. Moreover, Si, Ca, Sc, V, Cr, Mn, Fe, Cu, Zn, Y, Zr, Nb, Mo, Sn, La, Ce, Nd, and Gd elements are introduced into the Mg/Ti interface layer or interfacial sublayer of the HCP2 configurations, and their interfacial segregation behavior is investigated systematically. The results indicate that Gd atom doping in the Mg(0001)/Ti(0001) interface exhibits the smallest heat of segregation, with a value of −5.83 eV. However, Ca and La atom doping in the Mg(0001)/Ti(0001) interface show larger heat of segregation, with values of 0.84 and 0.63 eV, respectively. This implies that the Gd atom exhibits a higher propensity to segregate at the interface, whereas the Ca and La atoms are less inclined to segregate. Moreover, the electronic density is thoroughly analyzed to elucidate the interfacial segregation behavior. The research findings presented in this paper offer valuable guidance and insights for designing the composition of magnesium-based composites.

High-manganese austenitic steel represents an innovative variety of low-temperature steel used in the construction of liquefied natural gas (LNG) storage tanks. This steel boasts remarkable characteristics such as exceptional plasticity, superior toughness at cryogenic temperatures, and robust fatigue resistance, all while providing significant cost benefits. By utilizing high-manganese steel, the material manufacturing costs can be considerably lowered, simultaneously ensuring the long-term stability and safety of LNG storage tanks. The alloying design is pivotal in attaining superior performance in high-manganese steel. Choosing the right chemical components to control the stacked fault energy (SFE) of high-manganese steel and fine-tuning its structure can further improve the balance between strength and plasticity. Summarizing the advancements in alloying design for high-manganese steel is of great importance, as it offers a foundational dataset for correlating the chemical composition with the performance. Therefore, this paper outlines the deformation mechanisms and the principles of low-temperature brittleness in high-manganese austenitic steel, and from this foundation, it explicates the precise functions of alloying elements within it. This aims to provide a reference for future alloying designs and the industrial deployment of high-manganese steel in LNG storage tanks.

Heat-resistant materials, applied to manufacturing high-temperature components, are pivotal for raising the steam temperature parameters of advanced ultra-supercritical power plants. Alumina-forming austenitic (AFA) stainless steel, a promising candidate material applied to manufacture high-temperature components in fossil-fired ultra-supercritical steam plants, has been concerned by researchers. In this review, the recent progress of AFA steels with considerations of precipitations, high-temperature creep properties, and oxidation resistance was summarized. The stability of precipitates at high temperatures was discussed along with their competitive precipitation behavior. Furthermore, the factors which affect high-temperature creep properties of AFA steels were discussed. Simultaneously, the oxidation behaviors of AFA steels in diverse settings were evaluated.

The study presents the results of research on the influence of different contents of main alloying additions, such as Mg (2 ÷ 2.5 wt.%), Cu (1.2 ÷ 1.9 wt.%), and Zn (5.5 ÷ 8 wt.%), on the strength properties and plasticity of selected Al–Zn–Mg–Cu alloys extruded on a bridge die. The test material variants were based on the EN AW-7075 alloy. The research specimens, in the form of 100 mm extrusion billets obtained with the DC casting method, were homogenized and extrusion welded during direct extrusion on a 5 MN horizontal press. A 60 × 6 mm die cross-section was used, with one bridge arranged in a way to extrude a flat bar with a weld along its entire length. The obtained materials in the F and T6 tempers were characterized in terms of their strength properties, hardness, and microstructure, using EBSD and SEM. The extrusion welding process did not significantly affect the properties of the tested materials; the measured differences in the yield strength and tensile strength between the materials, with and without the welding seam, were up to ±5%, regardless of chemical composition. A decrease in plasticity was observed with an increase in the content of the alloying elements. The highest strength properties in the T6 temper were achieved for the alloy with the highest content of alloying elements (10.47 wt.%), both welded and solid. Significant differences in the microstructure between the welded and solid material in the T6 temper were observed. [ABSTRACT FROM AUTHOR]

The hot corrosion behaviors of Inconel alloys with different Cr contents (Inconel 600, 601, and 690), which are used widely in nuclear plants, were investigated in molten LiCl–Li2O salts. The hot corrosion behaviors were studied by measuring the mass and attack depth changes, surface and cross-sectional morphologies and elemental distributions, and compositional changes at the subscale and substrate scale as well as the spalled oxide scale. At 288 h, the weight losses of Inconel 601 and Inconel 690 were approximately four and twelve times higher, respectively, than that of Inconel 600. The corrosion products of all tested alloys were Cr2O3, NiO, and FeCr2O4. Inconel 600, which exhibited a dense and continuous external corrosion layer and an internal corrosion layer with localized corrosion behavior, exhibited superior corrosion resistance compared with those of Inconel 601 and 690, which showed a spalled external corrosion layer and an internal corrosion layer with uniform corrosion behavior. Thus, the corrosion resistance of the Inconel alloys tested in the hot lithium molten salts in an oxidizing atmosphere is closely related to the contents of the primary alloying elements in the alloys. Of the various alloys analyzed in this study, Inconel 600 exhibited the highest corrosion resistance. Thus, a Cr content of 16.30 wt% or less, Ni content of at least 73.66 wt%, and Fe content considerably lower than 8.15 wt% can result in excellent corrosion resistance. [ABSTRACT FROM AUTHOR]

The paper presents the influence of impurities and alloying elements on the properties and characteristics of aluminum sheets. The researches were carried out on the Stucco aluminum sheet with dimensions of 120 × 50 × 85 mm, used to make billboards, roofs, containers, films, kitchenware, chemical equipment, vaporizers for refrigerators, etc. The sheet is made of non-alloyed aluminum, according to the EN-AW 1050 standard and belongs to the 1xxx class. The sheets have a high percentage of aluminum in their chemical composition, approximately 99.5%. The aim of the work was to subject the samples from this type of material to mechanical tensile stress and to measure their modulus of elasticity. [ABSTRACT FROM AUTHOR]

Electrical steels play a crucial role in modern electrical devices and power systems due to their exceptional magnetic properties. This comprehensive review delves into the advancements in the field of electrical steels, focusing on key aspects such as microstructure, loss analysis, magnetic properties, alloying elements, and the influence of coatings. The microstructural characteristics of electrical steels are explored in relation to their impact on magnetic behaviour and overall performance. Loss analysis techniques are discussed, highlighting the importance of minimizing energy dissipation in applications. The intricate relationship between magnetic properties and material composition, including the role of alloying elements, is examined to elucidate the mechanisms governing magnetic behaviour. Furthermore, the influence of coatings on the performance of electrical steels is investigated, considering both protection against environmental factors and their impact on magnetic properties. Through a comprehensive synthesis of recent research, this review provides valuable insights into the multifaceted nature of electrical steels and sets the stage for further advancements in their design and application. [ABSTRACT FROM AUTHOR]

In this work, the effects of the micro-alloying of Mn, Ni, and Si on the microstructure and mechanical properties of high-carbon pearlite steels were investigated. The results indicated that the addition of solely Ni to high-carbon pearlitic steel can enhance the strength through the refinement of interlamellar spacing, but work-hardening in the ferrite of the pearlite colony may be delayed, leading to a reduction in area. The multiple additions of Ni and the increase in Mn and Si contents in high-carbon pearlitic steel were beneficial to obtaining a balance between ultimate tensile strength and reduction in area. Three-dimensional atom probe tomography results showed Si partitioning into ferrite and Mn and Ni elements partitioning into cementite. The addition of Si inhibited the formation of a continuous network of grain-boundary cementite, leading to high strength and high ductility through optimization of the microstructure. [ABSTRACT FROM AUTHOR]

The fluidity of liquid-phase zinc not only directly influences the casting properties of the alloy but also has a very important significance for the control of hot-dip galvanized coating thickness. The addition of various trace alloying elements to liquid-phase zinc can improve the fluidity, hence improving the coating effectiveness and surface quality of hot-dip zinc coatings, as well as improving the die-casting filling properties of liquid-phase zinc. In this paper, the influences of common alloying elements (Pb, Bi, Sn, Sb, Al, Mg, RE, Ni) used in hot-dip zinc and some alloying elements (Al, Mg) used in die-cast zinc alloys on liquid-phase zinc fluidity were reviewed.

The present study focuses on the dry and wet end milling of three distinct Aluminum 7075 alloys: A7075, A7075–Sc (with a 0.18% Sc addition), and A7075–Li–Sc (containing 2.2% Li and 0.18% Sc additions). The main objective is to explore how cutting parameters (cutting speed and feed rate), heat treatment, alloy composition, and cooling methods influence A lcutting force. In the initial phase of the investigation, all three alloys underwent heat treatment. Subsequently, the machining process centered on the softest and hardest conditions, aiming at analyzing the impact of hardness on machinability behavior of the three studied alloys, using the same milling tool and a consistent depth of cut under both dry and wet conditions. The investigations also highlight the role of Li and Sc additions on the quality of surface finish, as well as burr and chip formation. In total, a sum of 108 operations have been performed on the present alloys.

Cupronickel alloys have found widespread use in various applications such as heat exchangers, refrigeration systems, equipment, pumps, and pipes. However, the inherent structure of cupronickel alone may not be able to withstand certain aggressive environments effectively. To address this issue, the mechanical properties and corrosion resistance of cupronickel alloys can be enhanced by carefully selecting the appropriate alloying compositions. The addition of nano chromium (20 nm) has been proposed as a means of designing cupronickel alloys with improved performance. In the present study, corrosion and erosion–corrosion behaviors of cupronickel 70/30 alloys produced by the casting method without and with three different additions of nano Cr (1, 1.2, and 1.5 wt%) were investigated. The prepared specimens were subjected to electrochemical tests in 3.5 wt% sodium chloride solutions to evaluate their corrosion behavior. Additionally, an erosion–corrosion test was conducted at an impact angle of 90°, using a slurry solution containing 1 wt% SiO2 sand in 3.5 wt% NaCl solution as the erodent. The specimens were comprehensively characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. The surfaces of the alloy specimens exhibited superficial attacks, but no pits were observed. Moreover, the surfaces developed a greenish coloration. The electrochemical tests conducted using saline solution revealed that the corrosivity of the cupronickel alloy with nano chromium addition varied from moderate to low, depending on the selected concentration. Despite undergoing corrosion in the saline environment, the modified cupronickel alloys demonstrated good resistance to this corrosive process. Therefore, they can be considered suitable for use in highly aggressive environments, such as in seawater capture systems. The erosion–corrosion test results indicated that the addition of nano chromium significantly enhanced the resistance of the specimens to erosion–corrosion. At 1.5 wt% Cr, the erosion–corrosion rate was reduced by 99.27%.

Nickel‐based alloys are well‐known multicomponent alloys with a composition carefully balanced to provide the desired properties for various industrial applications. While these alloys are corrosion resistant, under severe conditions corrosion can still occur, which can result in serious damage to a system in operation. To improve their reliability, the composition of nickel‐based alloys can be tailored to particular operating conditions. To improve their corrosion resistance, alloying elements such as chromium, molybdenum (+tungsten), and copper can be added, which promote the oxide formation process and thereby contribute to oxide passivity. This paper reviews and draws conclusions from existing literature on nickel‐based alloy corrosion and oxide formation in high‐temperature environments. [ABSTRACT FROM AUTHOR]

This study shows that in an atmosphere containing water vapor, the oxide layer on the surface of the 9CrNB steel MarBN (Martensitic 9Cr steel strengthened by Boron and MX Nitrides) was formed by an outer layer of hematite Fe2O3 and Cr2O3 and an inner two-phase layer of Fe3O4 and Fe3O4 + (Fe, Cr)2O4, which was confirmed by XRD analysis. Part of the layer consisted of nodules and pores that were formed during the increase in oxides when the present H2O(g) acted on the steel surface. The diffusion mechanism at temperatures of 600 and 650 °C and at longer oxidation times supported the "healing process" with a growing layer of Fe oxides and the presence of Cr and minor alloying elements. The effects of alloying elements were quantified using a concentration profile of the oxide layer based on quantitative SEM analysis, as well as an explanation of the mechanism influencing the structure and chemical composition of the oxide layer and the steel-matrix–oxide interface. In addition to Cr, for which the content reached the requirement of exceeding 7.0 wt. % in the inner oxide layer, W, Co, Mn, and Si were also found in increased concentrations, whether in the form of the present Fe-Cr spinel oxide or as part of a continuously distributed layer of Mn2O3 and SiO2 oxides at the steel-matrix–oxide interface. After long-term high-temperature oxidation, coarser carbides of the M23C6 type (M = Fe,W) significantly depleted in Cr were formed at the oxide-layer/matrix interface. In the zone under the oxide layer, very fine particles of MC (M = V, Nb, and to a lesser extent also Cr in the particle lattice of the given phase) were observed, with a higher number of particles per unit area compared to the state before oxidation. This fact was a consequence of Cr diffusion to the steel surface through the subsurface zone. [ABSTRACT FROM AUTHOR]

Copper-based diamond composites have been the focus of many investigations for higher thermal conductivity applications. However, the natural non-wetting behavior between diamond particles and copper matrix makes it difficult to fabricate copper-based diamond composites with high thermal conductivity. Thus, to promote wettability between copper and diamond particles, the copper/diamond interface must be modified by coating alloying elements on the diamond surface or by adding active alloying elements with carbon in the copper matrix. In this paper, we review the research progress on copper-based diamond composites, including theoretical models for calculating the thermal conductivity and the effect of process parameters on the thermal conductivity of copper-based diamond composites. The factors that affect interfacial thermal conductivity are emphatically analyzed in this review. Finally, the current problems of copper-based diamond composites and future research trends are recommended. [ABSTRACT FROM AUTHOR]

Alloying control is an effective method to improve the corrosion resistance of low alloy structural steels. Different kinds of alloying elements have different influence law on the corrosion resistance of steels. In order to explore the effective method to improve the corrosion resistance of steel, the distribution law of alloying elements in steel as well as its influence mechanism and law on the corrosion resistance of steels were summarized in this paper. The research direction of regulation of the new generation of corrosion resistant steel in China was prospected. It was expected to provide a theoretical reference for the development of corrosion resistance regulation theory of low alloy structural steel and the research and development of a new generation of corrosion resistant low alloy steel in China.