Problems Of Metallurgy Research Articles

Strong resistance to hydrogen embrittlement of high-performance superalloy MP35N under 200 MPa (≈30,000 psi) H2 gas pressure

ABSTRACT Embrittlement of steels and alloys in contact with hydrogen gas under pressure is a key problem in metallurgy with important implications for a future energy economy based on hydrogen. Here we report stress–strain measurements recorded under 200 MPa (∼30,000 PSI) hydrogen gas pressure to evaluate the resistance of MP35N to embrittlement. We find that MP35N with a tensile strength of more than 1800 MPa does not suffer any strength loss, retains a significant amount of ductility and hence appears to be highly resistant to hydrogen embrittlement even under elevated stress when exposed over a time-scale of hours. This exceptional resistance to H-embrittlement seems to be unique among all high-performance steels and alloys of comparable strength and bears on the use of this material for high pressure H2 research devices and storage applications.

Study on Oxidation Behavior of Industrial Basic Oxygen Furnace Slag and Recovery of Magnetic Iron‐Containing Phase

The BOF slag contains a lot of iron‐containing species and its efficient recovery is a difficult problem in metallurgy. Herein, the oxidation behavior of industrial BOF slag under air atmosphere is investigated to explore the optimal oxidation conditions for transforming nonmagnetic FeO into magnetic MgFe2O4, including oxidation temperature, oxidation time, and airflow rate. The raw slag and oxidized slags are analyzed using chemical analysis, X‐ray diffraction (XRD) analysis, scanning electron microscope (SEM)‐energy dispersive spectroscopy (EDS) analysis, and Factsage thermodynamic simulation. The results show that the formation of MgFe2O4 phase is closely related to the oxidation temperature, oxidation time, and airflow rate. With the increase in temperature, the conversion rate of MgFe2O4 increases, and reaches the maximum at 1050 °C. However, the conversion rate of MgFe2O4 decreases and part of β‐C2S is converted to α‐C2S above 1050 °C. When the oxidation time and airflow rate increase, the conversion rate of MgFe2O4 increases and reaches the maximum value at 100 min and 1.25 L min−1, respectively. Correspondingly, the grade increased from 16.3% of the raw slag to 27.86% of the magnetic slag, an increase of 11.5%. This is a more convenient and effective method, which can not only bring economic benefits for relevant enterprises but also reduce environmental pollution.

On the Issue of Alloying and Modification of Alloys: Using the Waste Products for Creation of Novel Materials

At the large and powerful industrial (private or state) enterprises of the world, particularly, Kazakhstan, RF, and some other post-Soviet (and not only) countries, the products are manufactured using obsolete technologies with high wastes’ generation. At that, the storage and warehousing are unorganized and technically unreasonable (wastes of different chemical compositions and hazard class are mixed) that does not allow their further efficient recycling. Increased processing of many industrial and household wastes is not only economical, but also considerably improves the environmental situation, significantly reduces the consumption of natural raw materials, and reduces the use of scarce lands for waste storage [1]. The authors of this article carried out a literary review on this topic and attempted to use microsilica, as a waste of silicon production, to create new materials with special properties. This refers to the field of experimental study of structures, phases, structural components for understanding the processes of alloying, modification, diffusion, etc. Understanding physical thinking from the metal physics point of view in the study of the nature and kinetics of the phase transformations, alloying, and modification processes enables using the physical research methods to solve research and technological problems in metallurgy and materials science in order to predict and change the required set of properties. The method of research in this article is electron microscopy as the simplest and fastest method of obtaining information about the microstructure, elemental composition, and distribution of components in the bulk.

The use of artificial intelligence technologies in solving practical problems of metallurgy

The use of artificial intelligence technologies in solving practical problems of metallurgy

Machine Learning for Energy Systems

The objective of this editorial is to overview the content of the special issue “Machine Learning for Energy Systems”. This special issue collects innovative contributions addressing the top challenges in energy systems development, including electric power systems, heating and cooling systems, and gas transportation systems. The special attention is paid to the non-standard mathematical methods integrating data-driven black box dynamical models with classic mathematical and mechanical models. The general motivation of this special issue is driven by the considerable interest in the rethinking and improvement of energy systems due to the progress in heterogeneous data acquisition, data fusion, numerical methods, machine learning, and high-performance computing. The editor of this special issue has made an attempt to publish a book containing original contributions addressing theory and various applications of machine learning in energy systems’ operation, monitoring, and design. The response to our call had 27 submissions from 11 countries (Brazil, Canada, China, Denmark, Germany, Russia, Saudi Arabia, South Korea, Taiwan, UK, and USA), of which 12 were accepted and 15 were rejected. This issue contains 11 technical articles, one review, and one editorial. It covers a broad range of topics including reliability of power systems analysis, power quality issues in railway electrification systems, test systems of transformer oil, industrial control problems in metallurgy, power control for wind turbine fatigue balancing, advanced methods for forecasting of PV output power as well as wind speed and power, control of the AC/DC hybrid power systems with renewables and storage systems, electric-gas energy systems’ risk assessment, battery’s degradation status prediction, insulators fault forecasting, and autonomous energy coordination using blockchain-based negotiation model. In addition, review of the blockchain technology for information security of the energy internet is given. We believe that this special issue will be of interest not only to academics and researchers, but also to all the engineers who are seriously concerned about the unsolved problems in contemporary power engineering, multi-energy microgrids modeling.

Research of plasma impact on migration of silicon in ceramic substrates prepared on the basis of MgO

To solve a number of problems in metallurgy and construction, it seems promising to obtain physical and chemical methods of coatings on ceramic materials. In particular, the plasma-arc method makes it possible to obtain coatings with a thickness of 100–200 μm from oxides and carbides. To solve this problem, it is necessary to investigate the interaction processes of the ceramic substrate and the coating that occur during plasma spraying. In this work, ceramics with different Si contents with a deposited Al2O3 coating were selected as the object of study.

On Best Corrected Mixture Problems in Metallurgy: A Case Study

We consider three simple mixture problems occurring in metallurgy. The first problem considered is the classic minimum cost mixture problem. For the second problem, we consider finding a correction to a given mixture, a premix, without considering the cost of this premix. We only consider the cost and the weight of the quantity used as a correction. We show that the minimum cost correction does not correspond to the minimum weight correction, and we built the Pareto curve that gives all intermediate solutions between these two extreme solutions. Finally, the third problem is the correction problem for a nonfree premix. The correction is done to obtain a minimum cost corrected mixture.

Analysis of a numerical benchmark for columnar solidification of binary alloys

During the solidification of metal alloys, chemical heterogeneities at the scale of the product develop. It is referred to as "macrosegregation". Numerical simulation tools exist in the industry. However, their predictive capabilities are not validated and are still limited. A 2D numerical benchmark is presented, based on the solidification of metallic Pb-Sn alloys. Concerning the numerical benchmark, a "minimal" common model of solidification is assumed, including columnar growth without undercooling, fixed solid, isotropic permeability of the mushy region, local thermodynamic equilibrium, lever-rule assumption for the local average composition. We focus our attention on the numerical method used to solve the average conservation equations: Finite Volume, Finite Element, Velocity-Pressure coupling treatment, scheme for convective terms, etc. At this stage of the work, we cannot exhibit a reference solution. However we draw some conclusions on the effects of the grid dependency, in particular on the location and sizes of the segregate channels. The development of both thermally and solutal driven convections in the first stage of the process (cf. low Prandtl and high Lewis numbers) and the relative independency of the convective scheme are also discussed. This presentation also have the goal to call other contributors to join this benchmark [1] in order to enrich the exercise and to reach a reference solution for this important problem in metallurgy.

Nucleation problems in metallurgy of the solid state: recent developments and open questions

Nucleation processes play a key role in the microstructure evolution of metallic alloys during thermomechanical treatments. These processes can involve phase transformations (such as precipitation) and structural instabilities (such as recrystallisation). Although the word ‘nucleation’ is used in both cases, the situation is profoundly different for precipitation and for recrystallisation on which this article is focussed. In the case of precipitation, species are conserved and the underlying physics is stochastic fluctuations, allowing the apparition of critical germs of the new phase. In the case of recrystallisation, the underlying physical phenomenon is the progressive growth of subgrain structures leading to an unstable configuration, allowing a dislocation free grain to grow at the expense of a dislocated one. The two cases require different types of modelling which are presented in the article. To cite this article: Y. Bréchet, G. Martin, C. R. Physique 7 (2006).

The nonlinear algorithm of adaptive identification

In work is considered the generalized iterative algorithm of nonlinear adaptive model in distinction of the particular algorithm described in [4]. The functioning of such class of algorithms, so as the class of linear algorithms [5], is determined with state of adaptive identification [6], functioning of statistic modelling system [3], the stochastic properties of identification of plants of metallurgic processes [2]. This algorithm has self-adjusting properties and can successfully function during the identification of complex processing objects with time varying parameters. Some aspects of using such algorithms for identification problems in metallurgy are described.

The Application of Theoretical Knowledge to the Study of Metals

The topic Metals in the school chemistry syllabus[for the tenth grade] is divided into three sections. In the first, pupils are given a general orientation on the structure and properties of metals; in the second, they examine these properties, the occurrence of metals in nature, and the uses of various metals and their compounds; and in the third, they take up the problems of metallurgy.

Field-ion microscopy: Recent advances and present problems

It is now 21 years since Müller first published details of the operation of the field-ion microscope. In spite of early promise, this technique has been slow in contributing to fundamental research. New technological developments, in particular the atom probe and the channel plate intensifier, have done much to remove the ambiguity of earlier results. The field-ion microscope has been applied to a wide range of problems in Metallurgy and Surface Physics, but an improved theory of the technique is urgently required. It is unfortunate that the advances that have taken place over the past ten years have been primarily experimental and technological rather than theoretical. At the present time there is little chance of the field-ion microscope becoing a routine tool for solid state research.

Some fundamental ideas in topology and their application to problems in metallurgy

The topological ideas and results that have been used by metallurgists, together with several results not previously presented in the metallurgical literature, are developed in a systematic manner. Based on this presentation, a review is given of the use of topology in metallurgy. The additional topology that is introduced includes the Alexander duality theorem, the Euler-Poincare formula, and the concept of deformation retract. These concepts are used to establish interrelationships among the results of several papers and to clarify the mathematical treatment.

Magnetometallurgy—Applications and Techniques

The use of measurements of intrinsic magnetic properties—susceptibility, saturation magnetization, and transition temperature—in solving problems in metallurgy is discussed. Applications to phase-diagram determinations, precipitation studies, kinetics, detection of inhomogeneities, and quantitative analysis are considered. Methods of measurement requiring little capital investment are pointed out in the hope of stimulating metallurgy graduate students to apply magnetic analysis to their problems.

Heat Economy in Metal Melting

THE outstanding feature of the proceedings at the annual meeting of the Institute of Metals, held at Burlington House on March 21 and 22, was a general discussion on metal melting, organised by the council. Whether it was chiefly due to the fact that this subject aroused an unusual amount of interest among the members, or that war problems in metallurgy have created a desire to discuss those problems more freely than hitherto, the fact remains that in the last three months the institute has added more new members than it did in the previous two years; that the attendance was very much larger than it has ever been at any other meeting in the course of its history; and that the discussions on the various papers contributed were of unusual fullness and value.

Iron and Steel Institute

THE annual general meeting of the Iron and Steel Institute was held on May 8 and 9. Sir William RobertsAusten, K C.B., the retiring president, announced that Andrew Carnegie Research Scholarships, each of the value of 100l., had been awarded to Dr. A. Stansfield (London), to Dr. J. A. Mathews (New York) and to Mr. J. Goldberg (Leoben, Austria). Mr. Carnegie announced his intention of doubling his original donation for the purpose of founding these scholarships. Mr. William Whitwell was then inducted into the presidential chair. Having presented the Bessemer Gold Medal for 1901 to Mr. John Edward Stead, in recognition of the value of his investigations of the physical and chemical properties of iron and steel, the president delivered his inaugural address, in which he reviewed the scientific and industrial achievements of the past reign, and enumerated some of the most important problems in metallurgy that still await solution. A vote of thanks to the president for his admirable address was proposed by Mr. Carnegie and seconded by Sir Lowthian Bell.