A data identifier (DID) is an essential tag or label in all kinds of databases—particularly those related to integrated computational materials engineering (ICME), inheritable integrated intelligent manufacturing (I3M), and the Industrial Internet of Things. With the guidance and quick acceleration of the development of advanced materials, as envisioned by official documents worldwide, more investigations are required to construct relative numerical standards for material informatics. This work proposes a universal DID format consisting of a set of build chains, which aligns with the classical form of identifier in both international and national standards, such as ISO/IEC 29168-1:2000, GB/T 27766–2011, GA/T 543.2–2011, GM/T 0006–2012, GJB 7365–2011, SL 325–2014, SL 607–2018, WS 363.2–2011, and QX/T 39–2005. Each build chain is made up of capital letters and numbers, with no symbols. Moreover, the total length of each build chain is not restricted, which follows the formation of the Universal Coded Character Set in the international standard of ISO/IEC 10646. Based on these rules, the proposed DID is flexible and convenient for extending and sharing in and between various cloud-based platforms. Accordingly, classical two-dimensional (2D) codes, including the Hanxin Code, Lots Perception Matrix (LP) Code, Quick Response (QR) code, Grid Matrix (GM) code, and Data Matrix (DM) Code, can be constructed and precisely recognized and/or decoded by either smart phones or specific machines. By utilizing these 2D codes as the fingerprints of a set of data linked with its cloud-based platforms, progress and updates in the composition–processing–structure–property–performance workflow process can be tracked spontaneously, paving a path to accelerate the discovery and manufacture of advanced materials and enhance research productivity, performance, and collaboration.
Macroscopic materials are heterogeneous, multi-elementary, and complex. No material is homogeneous or isotropic at a certain small scale. Parts of the material that differ from one another can be termed ‘‘natural chips.” At different spots on the material, the composition, structure, and properties vary slightly, and the combination of these slight differences establishes the overall material performance. This article presents a state-of-the-art review of research and applications of high-throughput statistical spatialmapping characterization technology based on the intrinsic heterogeneity within materials. Highthroughput statistical spatial-mapping uses a series of rapid characterization techniques for analysis from the macroscopic to the microscopic scale. Datasets of composition, structure, and properties at each location are obtained rapidly for practical sample sizes. Accurate positional coordinate information and references to a point-to-point correspondence are used to set up a database that contains spatialmapping lattices. Based on material research and development design requirements, dataset spatialmapping within required target intervals is selected from the database. Statistical analysis can be used to select a suitable design that better meets the targeted requirements. After repeated verification, genetic units that reflect the material properties are determined. By optimizing process parameters, the assembly of these genetic unit(s) is verified at the mesoscale, and quantitative correlations are established between the microscale, mesoscale, macroscale, practical sample, across-the-scale span composition, structure, and properties. The high-throughput statistical spatial-mapping characterization technology has been applied to numerous material systems, such as steels, superalloys, galvanization, and ferrosilicon alloys. This approach has guided the composition and the process optimization of various materials.
Ni–Ti–based shape memory alloys (SMAs) have found widespread use in the last 70 years, but improving their functional stability remains a key quest for more robust and advanced applications. Named for their ability to retain their processed shape as a result of a reversible martensitic transformation, SMAs are highly sensitive to compositional variations. Alloying with ternary and quaternary elements to finetune the lattice parameters and the thermal hysteresis of an SMA, therefore, becomes a challenge in materials exploration. Combinatorial materials science allows streamlining of the synthesis process and data management from multiple characterization techniques. In this study, a composition spread of Ni–Ti–Cu–V thin-film library was synthesized by magnetron co-sputtering on a thermally oxidized Si wafer. Composition-dependent phase transformation temperature and microstructure were investigated and determined using high-throughput wavelength dispersive spectroscopy, synchrotron X-ray diffraction, and temperature-dependent resistance measurements. Of the 177 compositions in the materials library, 32 were observed to have shape memory effect, of which five had zero or near-zero thermal hysteresis. These compositions provide flexibility in the operating temperature regimes that they can be used in. A phase map for the quaternary system and correlations of functional properties are discussed with respect to the local microstructure and composition of the thin-film library.
This study was conducted to understand the relationship between various critical temperatures and the stability of the secondary phases inside the heat-affected-zone (HAZ) of welded Grade 91 (Gr.91) steel parts. Type IV cracking has been observed in the HAZ, and it is widely accepted that the stabilities of the secondary phases in Gr.91 steel are critical to the creep resistance, which is related to the crack failure of this steel. In this work, the stabilities of the secondary phases, including those of the M23C6, MX, and Z phases, were simulated by computational thermodynamics. Equilibrium cooling and Scheil simulations were carried out in order to understand the phase stability in welded Gr.91 steel. The effect of four critical temperatures—that is, Ac1 (the threshold temperature at which austenite begins to form), Ac3 (the threshold temperature at which ferrite is fully transformed into austenite), and the M23C6 and Z phase threshold temperatures—on the thickness of the HAZ and phase stability in the HAZ is discussed. Overall, the simulations presented in this paper explain the mechanisms that can affect the creep resistance of Gr.91 steel, and can offer a possible solution to the problem of how to increase creep resistance at elevated temperatures by optimizing the steel composition, welding, and heat treatment process parameters. The simulation results from this work provide guidance for future alloy development to improve creep resistance in order to prevent type IV cracking.
In the context of the current serious problems related to energy demand and climate change, substantial progress has been made in developing a sustainable energy system. Electrochemical hydrogen–water conversion is an ideal energy system that can produce fuels via sustainable, fossil-free pathways. However, the energy conversion efficiency of two functioning technologies in this energy system—namely, water electrolysis and the fuel cell—still has great scope for improvement. This review analyzes the energy dissipation of water electrolysis and the fuel cell in the hydrogen–water energy system and discusses the key barriers in the hydrogen- and oxygen-involving reactions that occur on the catalyst surface. By means of the scaling relations between reactive intermediates and their apparent catalytic performance, this article summarizes the frameworks of the catalytic activity trends, providing insights into the design of highly active electrocatalysts for the involved reactions. A series of structural engineering methodologies (including nanoarchitecture, facet engineering, polymorph engineering, amorphization, defect engineering, element doping, interface engineering, and alloying) and their applications based on catalytic performance are then introduced, with an emphasis on the rational guidance from previous theoretical and experimental studies. The key scientific problems in the electrochemical hydrogen–water conversion system are outlined, and future directions are proposed for developing advanced catalysts for technologies with high energy-conversion efficiency.
Herein, we report on the effect of a high gravity field on metal-free catalytic reduction, taking the nitrobenzene (NB) reduction and methylene blue (MB) degradation as model reactions in a highgravity rotating tube reactor packed with three-dimensional (3D) nitrogen-doped graphene foam (NGF) as a metal-free catalyst. The apparent rate constant (kapp) of the metal-free catalytic reduction of NB in the rotating tube reactor under a high gravity level of 6484g (g = 9.81 m·s-2) was six times greater than that in a conventional stirred reactor (STR) under gravity. Computational fluid dynamics (CFD) simulations indicated that the improvement of the catalytic efficiency was attributed to the much higher turbulent kinetic energy and faster surface renewal rate in the high-gravity tube reactor in comparison with those in a conventional STR. The structure of the 3D metal-free catalysts was stable during the reaction process under a high gravity field, as confirmed by X-ray photoelectron spectroscopy (XPS) and Raman spectra. In the other model reaction, the rate of MB degradation also increased as the high gravity level increased gradually, which aligns with the result for the NB catalytic reduction system. These results demonstrate the potential to use a high-gravity rotating packed tube reactor for the process intensification of metal-free catalytic reduction reactions.
The time-varying network topology can significantly affect the stability of multi-agent systems. This paper examines the stability of leader–follower multi-agent systems with general linear dynamics and switching network topologies, which have applications in the platooning of connected vehicles. The switching interaction topology is modeled as a class of directed graphs in order to describe the information exchange between multi-agent systems, where the eigenvalues of every associated matrix are required to be positive real. The Hurwitz criterion and the Riccati inequality are used to design a distributed control law and estimate the convergence speed of the closed-loop system. A sufficient condition is provided for the stability of multi-agent systems under switching topologies. A common Lyapunov function is formulated to prove closed-loop stability for the directed network with switching topologies. The result is applied to a typical cyber–physical system—that is, a connected vehicle platoon—which illustrates the effectiveness of the proposed method.
China is the largest producer and user of ordinary Portland cement (OPC), and the rapid growth of infrastructure development demands more sustainable building materials for concrete structures. Alkaliactivated materials (AAMs) are a new type of energy-saving and environmentally friendly building material with a wide range of potential applications. This paper compares the durability of AAMs and OPCbased materials under sulfate attack, acid corrosion, carbonation, and chloride penetration. Different AAMs have shown distinct durability properties due to different compositions being formed when different raw materials are used. According to the calcium (Ca) concentration of the raw materials, this paper interprets the deterioration mechanisms of three categories of AAMs: calcium-free, low-calcium, and calcium-rich. Conflicts found in the most recent research are highlighted, as they raise concerns regarding the consistence and long-term properties of AAMs. Nevertheless, AAMs show better durability performances than OPC-based materials in general.
In 2003, Railsback proposed the Earth Scientist's Periodic Table, which displays a great deal of elemental geology information in accordance with the natural environment of the earth. As an applied science, metallurgy is based on mineral composition and element behavior, that is similar to geochemistry. In this paper, connections and similarities between geology and metallurgy are identified, based on geochemical laws and numerous metallurgical cases. An obvious connection is that simple cations with high and low ionic potential are commonly extracted by hydrometallurgy, while those with intermediate ionic potential are extracted by pyrometallurgy. In addition, element affinity in geology is associated with element migration in metallurgic phases. To be specific, in pyrometallurgy, lithophile elements tend to gather in slags, chalcophile elements prefer the matte phase, siderophile elements are easily absorbed into metal melt, and atmophile elements readily enter the gas phase. Furthermore, in hydrometallurgy, the principles of hard/soft acids and bases (HSAB) offer an explanation of how precipitation and dissolution occur in different solutions, especially for fluoride and chloride. This article provides many metallurgical examples based on the principles of geochemistry to verify these similarities and connections.