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The alloying of platinum (Pt) with rare earth (RE) metals has emerged as a highly promising strategy for enhancing both the activity and stability of catalysts. Consequently, the development of methods for the controlled synthesis of Pt‐RE alloys has received growing attention. This review comprehensively explores diverse synthesis methodologies for Pt‐RE alloys, including physical metallurgy method, chemical reduction method, electrodeposition method, and dealloying method. Additionally, this review summaries the applications of Pt‐RE alloys in various fields. By providing a critical analysis of existing literature and highlighting key challenges and future directions, this review aims to offer valuable insights and serve as a springboard for further advancements in the controlled synthesis and diverse applications of Pt‐RE alloys. [ABSTRACT FROM AUTHOR]

The "Journal of Phase Equilibria & Diffusion" published a special issue in memory of Mats Hillert, a prominent figure in materials science who passed away in 2022. The issue celebrates what would have been his 100th birthday in 2024, highlighting his significant contributions to the field. Mats Hillert's pioneering work in thermodynamics and phase transformation, particularly in the development of the CALPHAD method, has left a lasting impact on the scientific community. His dedication to advancing scientific discourse and educating future generations in materials science is remembered fondly by colleagues and students alike. [Extracted from the article]

Gradient hierarchically porous structures are effective for enhancing catalytic reactions due to their capability of enabling fast mass transfer from solutions to inner active sites. However, facile and rational designing of the construction with uniform spatial gradients and high stability remains challenging. Here, a self‐supporting high‐entropy alloy (HEA) catalyst with a unique triple‐scale gradient porosity based on physical metallurgy is reported. The hierarchically porous structure of the catalyst can be effectively manipulated by tailoring the multi‐length scale phases of a negative mixing enthalpy FeCoNiCr‐Zr eutectic HEA. As an oxygen‐evolving catalyst, the hierarchically porous HEA demonstrates low overpotentials of 215 and 370 mV at 10 mA cm−2 and 1A cm−2, respectively. This is primarily attributed to the gradient mesoporosity providing abundant accessible reactive sites and exceptional intrinsic reactivity resulting from the synergistic electronic effects of multi‐component alloying. Furthermore, benefiting from the integrative gradient porosity that can suppress drastic gas bubble impact and the chemically stable configuration of inherent high‐entropy intermetallic compounds, the catalyst exhibits extraordinary durability for over 1000 h at 2 A cm−2. This work provides a new paradigm for developing high‐efficiency and low‐cost catalysts with robust gradient hierarchically porous structures for practical applications in various energy conversion technologies. [ABSTRACT FROM AUTHOR]

In the planar flow casting process of amorphous strips, the flow behavior of molten metal and the inclusion content in the crucible are crucial to the morphology and magnetic properties of the material. This study conducts a comparative analysis of the effects of non-immersed and immersed funnels, as well as various funnel structures, on the fluid flow and inclusion removal efficiency in the crucible by integrating numerical and physical models. The findings reveal that for the same pouring flow rate, the diameter of the liquid column in non-immersed pouring conditions is smaller than that of the funnel outlet, leading to a faster injection flow velocity. As a result, the melt in the crucible is subjected to severe impacts, accompanied by an increased possibility of slag entrapment. Conversely, immersed pouring substantially reduces the velocity of the molten metal at the funnel outlet, thereby extending the residence time in the crucible and diminishing the volume of the dead zone. Additionally, the molten metal backflows due to the negative pressure formed in the inner chamber of the funnel. The design of a trumpet-shaped funnel increases the effective volume while reducing the height of the backflow fluid, consequently reducing the velocity of the molten metal at the funnel outlet and prolonging the residence time. Compared to the conventional pouring process with the non-immersed funnel, the outlet velocity is reduced from 1.1 m/s to 0.12 m/s by adopting the immersed funnel with an inverted trapezoidal trumpet structure. This reduction results in a stable flow state, a 9.69% reduction in the dead zone volume fraction, and a 22.96% increase in average inclusion removal efficiency. These improvements demonstrate that a crucible funnel with a well-designed structure and the implementation of an immersion process can significantly improve the metallurgical effects in the planar flow casting process. [ABSTRACT FROM AUTHOR]

The steel industry represents a sector of great importance in the production chain, being directly related to the economic development of the world. The straightening process, an important phenomenon of plastic deformation during steel production can bring changes in the results of mechanical properties. The goal of this study is to analyze the interaction between the variables involved in the natural strain ageing, straightening (manual and mechanical) and in the chemical composition (low and medium carbon steels) of the wire rod, being the variation of the mechanical properties - through the tensile test – and microstructural – from the microstructural characterization – the analysis parameters. The results indicate a trend towards an increase in the yield and resistance limits of the materials that were submitted to the straightening and strain aging process, and it is possible to notice the pattern, from the contour and response surface graphs, that the higher the levels of straightening and percentage of carbon, the higher the values of yield strength and resistance.

The aim of this research work is to establish the theory of the domain of influence of diffusion disturbance with potential-temperature disturbance under the theory of generalized thermo-elastic diffusion using Lord and Shulman model. For a finite time t > 0, it has been proved that the potential due to displacement, temperature and diffusion effect does not produce any disturbances outside a bounded domain and the domain of influence is dependent on the support of thermo-elasto-diffusive load, the thermo-elasto-diffusive coupling constant and the phase-lag parameters. It has been shown that the domain of influence of the present case reduce to the domain of influence for classical thermo-elasticity theory with or without diffusion and the thermo-elasticity theory with one relaxation parameter without diffusion. Also, the effect of diffusion on thermal wave propagation is shown. This theorem will be applicable to analyze the deformation occur in elastic solids due to internal and external loads for the thermo-elasto-diffusive models and problems based on it in the field of engineering physics like solid-state-physics, physical metallurgy (fabrication of semi-conductor devices in mixture metals and molten semi-conductor), material engineering (separation of polymers), aircraft engineering, mechanical engineering and also in the industries like oil extraction from hydrocarbon and manipulation of macro-molecules like DNA etc. [ABSTRACT FROM AUTHOR]

With the development of the petroleum industry, the demand for materials for oilfield equipment is becoming increasingly stringent. The strength increase brought about by time strengthening is limited in meeting the needs of equipment development. The GH3625 alloy with different strength levels can be obtained through cold deformation and heat treatment processes. A study should be carried out to further develop the potential mechanical properties of GH3625. In this study, the GH3625 alloy was cold drawn with different reductions in area (0–30%) and heat treated, and its mechanical properties were tested. The microstructure of the alloy during deformation and heat treatment was characterized by methods such as optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) based on the principles of physical metallurgy. The strength increase caused by dislocation strengthening was calculated from the dislocation density, tested by X-ray diffraction (XRD). The calculated value was compared to the measured value, elucidating the strengthening effect of cold deformation and heat treatment. The results showed that the yield strength and yield ratio of the cold-drawn alloy significantly reduced after aging at 650 °C and 760 °C. Heat treatment can make a cold-deformed material recover, ablate dislocations, and greatly reduce the dislocation density in the microstructure of the GH3625 alloy, which was the main factor in the decrease in yield strength. The work-hardening gradient of the cold-drawn material varied greatly with different reductions in area. When the reduction in area was small (10%), the hardness gradient was obvious. When it increased to 30%, the alloy was uniformly strengthened as the deformation was transmitted to the axis. This study can provide more mechanical performance options for GH3625 alloy structural components in the petrochemical industry. [ABSTRACT FROM AUTHOR]

In order to quantify the reaction ability of phosphorus containing compounds in iron-based alloys such as hot metal or molten steel, and accurately evaluate their phosphorus removal degree, a thermodynamic prediction model for scientifically characterizing the reaction ability of structural units in the Fe–C–Mn–Si–P–S metallic melts has been established based on the Atom–Molecule Coexistence Theory (AMCT), macroscopic experiments, physical chemistry in metallurgy and computer science. Within the present studied metallic system and composition range, there is a strong linear correlation between the equilibrium mass percents of different atoms and molecules in the melt and their mass action concentration Ni calculated based on AMCT, of which iron phosphide compounds are the main phosphorus transport units. The mass action concentration of Fe2P shows a continuous linear strong correlation with the [mass pct P] in the initial and dephosphorized hot metal in the range of 0.02 to 0.31 pct. The equilibrium phosphorus removal ratio between the Fe–C–Si–Mn–P–S metallic melts and slag calculated based on AMCT shows a perfect linear relationship of 1:1 with the measured values. Iron phosphide compounds contribute the most to the total equilibrium phosphorus removal ratio, up to 99.9 pct, of which Fe2P contributes 68.7 pct. The dephosphorization ratio of hot metal measured based on industrial and laboratorial experiments shows a consistent linear trend with the equilibrium phosphorus removal ratio calculated based on AMCT, which indicates that AMCT can be correctly applied to study the phosphorus removal properties of hot metal or molten steel during the dephosphorization process. [ABSTRACT FROM AUTHOR]

In recent years, medium-entropy alloys (MEAs) have received significant focus for their innovative microstructure and design concept; they exhibit numerous excellent characteristics, making them ideal for several structural and functional applications. It is essential in materials science and engineering to explore how pressure affects the mechanical features of MEAs. We use ab initio simulations with Vienna ab initio Simulation Packages (VASP) and Molecular Dynamics (MD) with Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) to investigate the dislocation, elastic, and mechanical properties of cubic AlCrNi MEA. Dislocation-related properties include mean square atomic displacement (MSAD), critical resolved shear stress (CRSS), lattice distortion, and yield strength. Initially, numerous physical properties of AlCrNi MEA are determined, including the material's elastic stiffness, elastic moduli, ductility–brittleness, machinability index, Vickers hardness, Kleinman, as well as various anisotropy parameters. Then we investigate how pressure affects these physical properties. The importance of investigating the effect of pressure on the physical characteristics of AlCrNi MEA is highlighted by our simulation results, particularly for high-pressure applications. [ABSTRACT FROM AUTHOR]

Phase transformations during continuous cooling play a vital role in controlling final microstructure and mechanical properties of hot-rolled high-strength low-alloy (HSLA) steels. Therefore, accurate prediction of continuous cooling transformation (CCT) diagrams is the key to optimizing hot-rolling processes. But, because phase transformation behaviors are complex and the accumulated data are insufficient, it is of great difficulty to accurately model CCT diagrams. In this paper, a hereditary modeling method based on the combination theories of physical metallurgy (TPM) and machine learning (ML) is proposed. Through thermodynamic and kinetic analyses, the key factors affecting behaviors of continuous cooling transformation are clarified. Combined with the existed data, the feature parameters in direct correlations with phase transformation temperatures are obtained by theoretical calculations. By using the algorithm of support vector machine (SVM), the model for predicting CCT diagrams has been developed, demonstrating superior prediction accuracy over the traditional data-driven ML models, especially in predicting the temperatures for pearlite and bainite transformations. By applying the established ML models to industrial production of HSLA steel plates, their CCT diagrams were predicted and verified through metallographic observations of final microstructures formed under different cooling paths. [ABSTRACT FROM AUTHOR]

Medium Mn steels are an emerging class of 3rd generation advanced high-strength steels. These steels have received significant attention due to their high strengths, large ductilities and also lower cost compared to their predecessor high Mn Twinning Induced Plasticity (TWIP) steels. Additionally, medium Mn steels have been found to exhibit TWIP and/or Transformation Induced Plasticity (TRIP) effects which can be harnessed to give a high strain hardening rate. Many thermomechanical processing concepts in the literature have been developed, producing multiple microstructure types with differentmechanical properties. The present review therefore aims to summarise the current knowledge of medium Mn steel alloy design especially on the processing, microstructure and property relationships in medium Mn steels. It complements the review of Sun et al. [Physical metallurgy of medium-Mn advanced high-strength steels, Int Mater Rev. 2023.], written independently and in parallel, which focusses more on the phase interfaces and thermodynamics. [ABSTRACT FROM AUTHOR]

Steels with medium manganese (Mn) content (3∼12 wt-%) have emerged as a new alloy class and received considerable attention during the last decade. The microstructure and mechanical response of such alloys show significant differences from those of established steel grades, especially pertaining to the microstructural variety that can be tuned and the associated micromechanisms activated during deformation. The interplay and tuning opportunities between composition and the many microstructural features allow to trigger almost all known strengthening and strain-hardening mechanisms, enabling excellent strength-ductility synergy, at relatively lean alloy content. Previous investigations have revealed a high degree of microstructure and deformation complexity in such steels, but the underlying mechanisms are not adequately discussed and acknowledged. This encourages us to critically review and discuss these materials, focusing on the progress in fundamental research, with the aim to obtain better understanding and enable further progress in this field. The review addresses the main phase transformation phenomena in these steels and their mechanical behaviour, covering the whole inelastic deformation regime including yielding, strain hardening, plastic instability and damage. Based on these insights, the relationships between processing, microstructure and mechanical properties are critically assessed and rationalized. Open questions and challenges with respect to both, fundamental studies and industrial production are also identified and discussed to guide future research efforts. [ABSTRACT FROM AUTHOR]

Strain‐induced precipitation (SIP) plays an important role in controlling the microstructure and properties of micro‐alloyed steels during hot rolling. However, due to lack of systematic experiments, the existing precipitation data are scarce and insufficient for accurate modeling of SIP behavior with good extrapolation. Herein, the data space of Niobium Carbonitride (Nb(C,N)) SIP kinetics is analyzed based on principle of orthogonal design, and the missing points in the orthogonal space are identified and supplemented in addition to the available data. The parameters in models for precipitation start and finish times are optimized by using the precipitation–time–temperature curves through genetic algorithm, and their relationships with compositions and processing conditions are established by support vector machine. Based on the orthogonally modified dataset, the machine learning (ML) models outperform the classical and ML models with the original data in terms of accuracy and are in good agreement with theoretical expectations. By using the new ML modeling, the evolution behavior of Nb (C, N) during hot deformation is predicted and verified with transmission electron microscope, and the influences of Nb content in steel, strain, strain rate, and the sensitivity of compositions and processing conditions on precipitation kinetics are quantitatively analyzed. [ABSTRACT FROM AUTHOR]

Because wheel manufacturing requires dual-phase (DP) 590 steel with different thickness specifications, it is necessary to produce DP590 steel with good mechanical property stability through a controlled cooling process. According to the volume fraction of ferrite and martensite and the grain size of ferrite in DP590 steel with different plate thicknesses under industrial production conditions, the effects of strengthening and toughening mechanisms, such as fine grain strengthening and phase transformation strengthening, on mechanical properties are considered, and a prediction model of the microstructure-property relationship of DP590 steel is established. On this basis, the effects of thickness and processing parameters on the grain size and fraction of ferrite are analyzed, which show that the evolution of ferrite accord with physical metallurgy principles. Three DP590 steels are rolled by using the established microstructure-property relationship model, and the results show that the predicted results of the model are in good agreement with the experimental values. [ABSTRACT FROM AUTHOR]

Mechanical properties are an essential standard for V–N steel hot-rolled plates used in steel structures such as ship hulls, paint pipelines and offshore platforms. To solve the problems of low production efficiency and low applicability of the traditional physical metallurgy (PM) model, this study proposed an adequate model, namely eXtreme Gradient Boosting based on Bayesian optimization (BO-XGBoost). First, composition-process-yield strength data of V–N steel hot-rolled plate with steel grade Q550D were collected, and K nearest neighbor (KNN), support vector machine (SVR), multi-layer perception (MLP), random forest regression (RFR), gradient boosting regression (GBR) and XGBoost machine learning (ML) models were established using preprocessed data sets. Then, the Bayesian optimization method was used to optimize the hyperparameters of the RFR and XGBoost models with better performance. Therefore, the mechanical properties prediction model was established, and the impact of feature processing and PM parameters on the model was discussed. The results show that the BO-XGBoost model can effectively predict the mechanical properties of high-dimensional industrial big data and has excellent generalization ability (testing set Er = 93.52%, MAE = 13.56 MPa, RMSE = 20.19 MPa), which is suitable for large-scale and industrial production of V–N steel hot-rolled plate. [ABSTRACT FROM AUTHOR]

Increasing the strength of Al-based alloys is an important issue of physical metallurgy and industrial processing. Severe plastic deformation and related extension of solid solubility during mechanical alloying provide an opportunity for significant strengthening due to grain refinement, solid solution, and precipitation strengthening mechanisms. During mechanical alloying, an anomalous increase in the solid-state solubility of alloying elements occurs. The present study focuses on the investigation of the pre-milling treatment to the microstructure, phase composition, and solubility in Al-7.7 Mn-3.5 Cu (wt%) alloy processed by a high-energy ball milling of Al-14.3 Mn-6.5 Cu (wt%) master alloy diluted with Al powder. During milling, the mean granular size decreased to ~5 µm, and a strong grain refinement occurred. According to our TEM and XRD data, ball milling provided a mean grain size of 13–14 nm and a microhardness of 490–540 HV. The lattice parameter of the Al-based solid solution decreased with an increase in the milling time to 7.5–10 h, which suggested the dissolution of the alloying elements, and the lattice parameter increased at a higher milling time of 12.5–40 h, which suggested the decomposition of the solid solution. The XRD data revealed the dissolution of the Al6Mn and Al20Cu2Mn3 solidification-originated phases with a further precipitation of the Al6Mn dispersoids. Pre-milling of the master alloy entailed a significant decrease in the minimal lattice parameter value from 0.4029 nm to 0.4023 nm due to an increase in the Mn solute content from 6.2 wt% (3.3 at%) to 7.5 wt % (4.0 at%) in the studied alloy during high-energy ball milling. [ABSTRACT FROM AUTHOR]

[Display omitted] • NN-MEAM interatomic potentials were developed for Zr-(Co, Fe, Ni) binary alloys. • Structural, thermodynamic and elastic properties of alloys were reproduced. • The potentials help to study the atomic-scale behavior of Zr-containing alloys. • The potentials can be used to prepare interatomic potential for Zr-containing HEAs. The second nearest-neighbor modified embedded-atom method (2NN-MEAM) interatomic potentials were developed for Zr-X (X = Co, Fe, Ni) binary alloys. The structural, mechanical and thermodynamic properties of various stable and metastable phases in Zr-Co, Zr-Fe and Zr-Ni binary systems were calculated by molecular dynamic (MD) simulation using the developed 2NN-MEAM potentials. The results obtained by MD simulation using the 2NN-MEAM potentials exhibited good consistency with the experimental data or first-principles calculations. The potentials can be utilized to investigate the atomic scale physical metallurgy of Zr-based binary, multinary and high entropy alloys and adjust their composition and microstructure to meet the specific requirements entailed in harsh environments. [ABSTRACT FROM AUTHOR]

Interatomic potentials based on the second nearest-neighbor modified embedded-atom method (2NN-MEAM) have been developed for Fe-V and Cr-V binary alloys. The structural, mechanical and thermodynamic properties of various stable and metastable phases in Fe-V and Cr-V binary systems were calculated by molecular dynamic (MD) simulation using the developed 2NN-MEAM potentials. A good consistency between the MD-calculated data and the experimental data or first-principles calculations was obtained. The potentials were further employed to predict several chemically complex intermetallic alloys (CCIAs) with stable B2 and L1 2 ordered structures in CoCrFeNiTiV system. Finally, this work pave the way to investigate the atomic scale physical metallurgy of V-containing and chemically complex intermetallic alloys and adjust their composition and microstructure to meet the specific requirements entailed in advanced applications. [ABSTRACT FROM AUTHOR]

This study examined the interface microstructure that developed between 63Sn-37Pb (Sn-Pb) solder and the Au protective layer that was not fully consumed during the soldering process. This scenario leads to a Au interface embrittlement failure mode that places at risk high-reliability electronics using the eutectic Sn-Pb solder and Au protective finishes. The sessile drop test sample assessed the roles of solder thickness and solid-state aging (55–100°C; 5–40 days). The interface microstructure began with a contiguous, secondary Au-Sn intermetallic compound (IMC) layer adjacent to the Au layer and an accumulation of particles that would coarsen into the primary Au-Sn IMC layer next to the solder. The baseline condition, which was established by aging for 28 days at 25°C, caused a noticeable increase of Kirkendall voids along the Au/secondary Au-Sn IMC interface. The following trend was observed: Kirkendall voids increased with decreasing solder thickness. The risk of catastrophic failure was high when the solder thickness was < 50 µm; the risk was low when the solder thickness was > 100 µm. The thick solder layer also caused Kirkendall voids to develop within the secondary Au-Sn IMC grain structure and extended into the primary Au-Sn IMC layer. However, these voids posed a low risk to solder joint integrity. The Au interface embrittlement mechanism, which results from the incomplete removal of a Au protective finish, can lead to infant mortality failures prior to, or latent failures after, the solder joint has entered service. [ABSTRACT FROM AUTHOR]

The properties of a heat-resisting steel are influenced by the interaction of various processes specific to physical and mechanical metallurgy. For these steels to ensure the required service conditions, it is necessary to optimise the relationship between microstructure, microscopic deformation and macroscopic creep behaviour. The aim of this optimisation is to reveal some aspects of the possibilities of improving or developing heat resistant steels with high mechanical performance. In order for a heat-resisting steel to provide mechanical characteristics over long service lives, the condition of a low creep rate is required, which is achieved by increasing the interaction energy between atoms and dislocations, blocking slip and grain boundaries by a fine dispersion of stable phase particles. This dispersion is necessary to avoid uncontrolled structural transformations where discontinuous precipitation occurs. [ABSTRACT FROM AUTHOR]

The enhancement of both low-temperature impact toughness and the hardness of a high strength steel heat-affected zone (HAZ) is investigated by using high-density electropulsing (EP). The athermal and thermal effects of EP on HAZ microstructure and resultant mechanical properties were examined based on physical metallurgy by electron backscattered diffraction and on tests of hardness and impact toughness at −60 °C, respectively. EP parameters were carefully determined to avoid electro-contraction and excessive pollution of the base metal by using numerical simulation. The EP results show that the mean impact toughness and hardness of HAZ are 2.1 times and 1.4 times improved, respectively. In addition to the contribution of microstructure evolution, geometrically necessary dislocation (GND) is also a contributor with an increase of 1.5 times, against the slight decrease in dislocation line density and dislocation density. The mechanisms behind this selective evolution of dislocation components were correlated with the localized thermal cycle EP, i.e., the competition among thermo- and electro-plasticity, and work-hardening due to local thermal expansion. The selective evolution enables the local thermal cycle EP tailor the martensitic substructure that is most favorable for toughness and less for hardness. This selective span was limited within 4 mm for a 5 mm thick sample. The local thermal cycle EP is confirmed to be capable of enhancing in both toughness and hardness within a millimeter-scale region. [ABSTRACT FROM AUTHOR]

The properties of existing Ti-based alloys and composites are reviewed. The effect of various alloying elements, reinforcement, and technological parameters of the powder metallurgy on the physical and mechanical properties of Ti-based alloys and composites is studied. Post-treatment conditions are discussed and optimal ways to lower the residual porosity of the composites are suggested. [ABSTRACT FROM AUTHOR]

A density functional theory for the bulk phase diagram of two-dimensional orientable hard rods is proposed and tested against Monte Carlo computer simulation data. In detail, an explicit density functional is derived from fundamental mixed measure theory and freely minimized numerically for hard discorectangles. The phase diagram, which involves stable isotropic, nematic, smectic, and crystalline phases, is obtained and shows good agreement with the simulation data. Our functional is valid for a multicomponent mixture of hard particles with arbitrary convex shapes and provides a reliable starting point to explore various inhomogeneous situations of two-dimensional hard rods and their Brownian dynamics. [ABSTRACT FROM AUTHOR]

The axis of most commercially available bulk Terfenol-D rods is misaligned with the pseudo-cubic Terfenol-D crystals. Thus, the development of efficient and accurate constitutive models for Terfenol-D has traditionally been challenging. This study presents a fully coupled and efficient discrete energy-averaged model that describes the nonlinear magnetostrictive behavior of Terfenol-D. The model is built on the basis of the Stoner-Wohlfarth particle approximation, where the anhysteresis bulk response of magnetostrictive materials is considered as a weighted sum of local magnetic domain responses and the material hysteresis is defined by an evolution function for the weights. The local responses are explicitly calculated through minimizing the free energy of individual magnetic domains; the weights, also known as the domain volume fractions, are described by an energy-based Boltzmann distribution. Advanced computation algorithms are developed to further improve the model efficiency. The model is used to interpret magnetic flux density and strain measurements from multiple [112]-oriented Terfenol-D rods. According to the modeling results, the explicit constitutive model developed in this study is three to five times faster than the previous implicit discrete energy-averaged model while preserving accuracy. [ABSTRACT FROM AUTHOR]

Modeling precipitation in metallic alloys is a topic of great importance in physical metallurgy as the resulting strengthening strongly depends on the precipitate microstructure. We propose here a numerical full-field model for precipitation that describes precipitates with shape functions, thereby allowing to bridge scales between phase-field approaches - that accurately describe the precipitate evolution but require a fine discretization grid - and mean-field approaches - that are computationally very efficient but rely on strong assumptions. Our results demonstrate the capability of the full-field approach to model the different stages of precipitation during isothermal treatments. The comparison with mean-field results allow to discuss the influence of solutal impingement and precipitate coagulations on the evolution of the precipitate microstructure. [ABSTRACT FROM AUTHOR]

Various computational analysis systems based on machine learning (ML) methods have been established for the analysis of steel industrial data. However, limited by the extensibility of one regression strategy, it is difficult to obtain a generic property prediction model for multiple types of steels. To solve this problem, this study proposes a novel industrial big data analysis system that combines ML classification and regression models with key physical metallurgy (PM) variables. First, the database is obtained from an industrial production line and carefully preprocessed. Then, multiple types of steels are categorized into five classes using a K‐nearest neighbor (KNN) algorithm, and suitable ML algorithms are selected for each category to maximize the performance. Considering the role of PM variables in improving the model accuracy, some relevant parameters (the Ac1 temperature, Ac3 temperature, and flow stress) are introduced to guide the further optimization of the ML process. The proposed industrial analysis system has more accurate prediction and higher flexibility than the model that directly uses the original dataset. With a rational combination of different regression strategies, the present results clearly demonstrate that the extensibility of the proposed property prediction model is significantly improved for industrial big data. [ABSTRACT FROM AUTHOR]

Achieving a porous architecture with multiple‐length scales and utilizing the synergetic effects of multicomponent chemicals bring up new opportunities for further improving the electrocatalytic performance of nanocatalysts. Herein, the synthesis of a self‐supported hierarchical porous electrocatalyst based on a high‐entropy alloy (HEA) containing multiple transitional metals via physical metallurgy and dealloying strategies is reported. Microscale phase separation and nanoscale spinodal decomposition are modulated in a highly concentrated FeCoNiCu HEA, which makes it possible to obtain a porous structure with different length scales, i.e., relatively large porous channels formed by removing one separated phase and ultrafine mesopores obtained from leaching out one decomposition phase. The resultant hierarchical porous HEA exhibits superior water splitting performance, which takes full advantage of the enlarged surface area offered by the bi‐continuous mesoporous structure with the exceptional intrinsic reactivity originating from the synergetic electronic effects of the different components in alloying. Moreover, the microscale porous structure plays an important role in the significantly improved mass transportation, as well as the durability during electrocatalysis. This effective strategy that simultaneously utilizes the chemical and microstructural advantages of HEAs opens up a new avenue for developing HEA‐based, high‐performance porous electrocatalysts for various energy conversion/store applications. [ABSTRACT FROM AUTHOR]

Spheroidization is a process that uses a high temperature to change the properties of metals and it is often used in physical metallurgy. Metallographic inspection is an important method of inspecting the quality of metal materials after spheroidization. In the process of metallographic inspection, a high-power optical microscope combined with a digital camera is usually used to obtain an image of the spheroidized metal. A light sensor, which is a charge-coupled device in the camera, is used to convert the image observed by the microscope into an electronic image signal. In this paper, we present an image recognition method with a deep learning neural network (NN) to inspect the metallographic grade of spheroidized metal. Three different transfer learning models are incorporated in the NN structure for feature extraction for comparison. The overall aim of our study is to reduce the shortcomings and inconvenience of traditional manual inspection and increase the judgment accuracy of metallographic analysis. In experiments, 203 metallographic images of size 1536 × 2048 were used for the learning and testing of the NN. The metallographic grade of the spheroidized metal was evaluated using the deep learning NN model. [ABSTRACT FROM AUTHOR]

In the imaging of living cells, the detection results of refractive index and thickness distribution have always been important parameters in the analysis of cell variation and morphology. In optical phase imaging, due to the coupling effect of RI and thickness of cells, the RI of cells cannot be directly measured, hence the decoupling method of RI and thickness of cells has always been a hot topic in this field. This article focuses on the subject of blood cells based on the free lable three-dimensional phase imaging information to establish dual wavelength phase shift equation, and analyse it by the three-dimensional phase imaging under dual wavelength phase information distribution and gradient distribution characteristics and obtain mathematical result of decoupling of the RI and thickness of homogeneous and nucleated heterogeneous samples by the dual wavelength phase distribution function. The RI and the thickness distribution of the outer cell and the inner core are obtained through the simulation experiments of the single medium model and the spherical outer cell kernel model. The error analysis shows that the method is highly accurate, which verifies the correctness of the method of this article. The proposed method can be used to decouple the RI and thickness distribution of red blood cells and five subgroups of white blood cells, which can provide a new method for the analysis of blood cell abnormality and cell morphology. [ABSTRACT FROM AUTHOR]

The electric current exponent, typically with j-n form, is a key parameter to predict electromigration-induced failure lifetime. It is experimentally observed that the current exponent depends on different damage mechanisms. In the current research, the physical mechanisms including void initiation, void growth, and joule heating effect are all taken into account to investigate the current exponent variation regularity. Furthermore, a physically based model to predict the mean time to failure is developed and the traditional Black's equation is improved with clear physical meaning. It is found that the solution to the resulting void initiation and growth equation yields a current exponent of 2 and 1, respectively. On the other hand, joule heating plays an important role in failure time prediction and will induce the current exponent n>2 based on the traditional semi-empirical model. The predictions are in agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Flexible metallic interconnects are highly important in the emerging field of deformable/wearable electronics. In our previous work [Arafat et al., Appl. Phys. Lett. 107, 081906 (2015)], interconnect films of Indium metal, periodically bonded to an elastomer substrate using a thin discontinuous/cracked adhesion interlayer of Cr, were shown to sustain a linear strain of 80%-100% without failure during repeated cycling. In this paper, we investigate the mechanisms that allow such films to be stretched to a large strain without rupture along with strategies to prevent a deterioration in their electrical performance under high linear strain. Scanning Electron Microscopy and Digital Image Correlation are used to map the strain field of the Cr adhesion interlayer and the In interconnect film when the elastomer substrate is stretched. It is shown that the Cr interlayer morphology, consisting of islands separated by bi-axial cracks, accommodates the strain primarily by widening of the cracks between the islands along the tensile direction. This behavior is shown to cause the strain in the In interconnect film to be discontinuous and concentrated in bands perpendicular to the loading direction. This localization of strain at numerous periodically spaced locations preempts strain-localization at one location and makes the In film highly stretchable by delaying rupture. Finally, the elastic-plastic mismatch-driven wrinkling of the In interconnect upon release from first loading cycle is utilized to delay the onset of plasticity and allow the interconnect to be stretched repeatedly up to 25% linear strain in subsequent cycles without a deterioration of its electrical performance. [ABSTRACT FROM AUTHOR]

We study the phase behaviour of a binary mixture of colloidal hard spheres and freely jointed chains of beads using Monte Carlo simulations. Recently Panagiotopoulos and co-workers predicted [Nat. Commun. 5, 4472 (2014)] that the hexagonal close packed (HCP) structure of hard spheres can be stabilized in such a mixture due to the interplay between polymer and the void structure in the crystal phase. Their predictions were based on estimates of the free-energy penalty for adding a single hard polymer chain in the HCP and the competing face centered cubic (FCC) phase. Here we calculate the phase diagram using free-energy calculations of the full binary mixture and find a broad fluid-solid coexistence region and a metastable gas-liquid coexistence region. For the colloid-monomer size ratio considered in this work, we find that the HCP phase is only stable in a small window at relatively high polymer reservoir packing fractions, where the coexisting HCP phase is nearly close packed. Additionally we investigate the structure and dynamic behaviour of these mixtures. [ABSTRACT FROM AUTHOR]

Due to their high strength and advantageous high-temperature properties, tungsten-based alloys are being considered as plasma-facing candidate materials in fusion devices. Under neutron irradiation, rhenium, which is produced by nuclear transmutation, has been found to precipitate in elongated precipitates forming thermodynamic intermetallic phases at concentrations well below the solubility limit. Recent measurements have shown that Re precipitation can lead to substantial hardening, which may have a detrimental effect on the fracture toughness of W alloys. This puzzle of subsolubility precipitation points to the role played by irradiation induced defects, specifically mixed solute-W interstitials. Here, using first-principles calculations based on density functional theory, we study the energetics of mixed interstitial defects in W-Re, W-V, and W-Ti alloys, as well as the heat of mixing for each substitutional solute. We find that mixed interstitials in all systems are strongly attracted to each other with binding energies of -2.4 to -3:2 eV and form interstitial pairs that are aligned along parallel first-neighbor h111i strings. Low barriers for defect translation and rotation enable defect agglomeration and alignment even at moderate temperatures. We propose that these elongated agglomerates of mixed-interstitials may act as precursors for the formation of needle-shaped intermetallic precipitates. This interstitial-based mechanism is not limited to radiation induced segregation and precipitation in W-Re alloys but is also applicable to other bodycentered cubic alloys. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) technologies and advances made globally in medicine, construction, aerospace, and energy sectors are discussed. The paper further explores the current state of AM innovation and development landscape in Africa as a late comer to this area of smart manufacturing. Peer-reviewed and published literature were retrieved from Scopus database from 2005 to 2021 and analysed. In Africa, out of 500 published articles, South Africa has the highest research throughput, whereas about two-thirds of the continent is not actively participating in this burgeoning field. The main AM techniques most widely used are selective laser melting, fused deposition modelling, and direct energy deposition. Globally, there is an interplay of computational (machine learning and mechanistic models) and experimental approaches to understanding the physical metallurgy of AM techniques and processes. Though this trend is consistent with global practices, Africa lags the world in AM technologies, a niche that could leapfrog the manufacturing sector. Thus, Africa need to foster collaborative partnership within and globally to become an active global player in this industry. [ABSTRACT FROM AUTHOR]

Based on the need to fabricate new or modified materials that possess demanding mechanical and wear properties that are needed for operation in extreme environmental conditions, it is necessary to understand the fundamentals of such materials based on their physical metallurgy and fabrication techniques to match up with industrial growth. The unique properties of titanium and its alloys have prompted research into ways of improving their utilization as a potential candidate for applications in extreme conditions. A way to improve the mechanical properties of titanium and its alloy is to develop a titanium matrix composite by adding ceramic reinforcements and choosing the appropriate fabrication route and parameters. The development of titanium matrix composites, the fabrication methods, and the incorporation of reported research works are discussed in this review. This serves to give a wide range of understanding into the development of titanium matrix composites. [ABSTRACT FROM AUTHOR]