Journal Description
Metals
Metals
is an international, peer-reviewed, open access journal published monthly online by MDPI. The Portuguese Society of Materials (SPM), and the Spanish Materials Society (SOCIEMAT) are affiliated with Metals and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q2 (Metallurgy & Metallurgical Engineering) / CiteScore - Q1 (Metals and Alloys)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 15 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Companion journals for Metals include: Compounds and Alloys.
Impact Factor:
2.9 (2022);
5-Year Impact Factor:
2.9 (2022)
Latest Articles
Effect of Electromagnetic Power on the Microstructure and Properties of 2219 Aluminum Alloy in Electromagnetic Continuous Casting Technology
Metals 2024, 14(4), 393; https://doi.org/10.3390/met14040393 - 27 Mar 2024
Abstract
Electromagnetic continuous casting technology serves as a significant means for enhancing the casting performance of 2219 aluminum alloy. Investigating the influence of electromagnetic field variations on the solidification process is crucial for studying the microstructure and mechanical properties of electromagnetic cast billets. Through
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Electromagnetic continuous casting technology serves as a significant means for enhancing the casting performance of 2219 aluminum alloy. Investigating the influence of electromagnetic field variations on the solidification process is crucial for studying the microstructure and mechanical properties of electromagnetic cast billets. Through experimental research, variations in the microstructure and mechanical properties were examined for ordinary direct chill casting, as well as three different electromagnetic power casting ingots. The COMSOL software (COMSOL Multiphysics 6.0) was utilized to simulate the temperature and flow field, enabling an explanation of the resulting performance changes. The results showed the effect on electromagnetic continuous casting technology by the electromagnetic field generated by the Lorentz force and melt stirring, improving the melt flow and temperature distribution so that the melt center and the edge of the melt forcible convection were enhanced, thus realizing the tissue refinement, mechanical properties, and Cu element segregation of the improvement. With an increase in electromagnetic power, the distribution of the temperature field was more homogeneous, the segregation phenomenon was more alleviated, and the improvement in mechanical properties was more significant. The optimal microstructure and mechanical properties were achieved at a power of 20.0 kW, with a 74.7% improvement in grain refinement in the center and a tensile strength increase of 30.8%. Additionally, significant improvements were observed in segregation phenomena.
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Open AccessArticle
The Effect of Stearic Acid on Microstructure and Properties of (Ti2AlC + Al2O3)p/TiAl Composites
by
Jiawei Zhu, Meini Yuan, Xin Pei, Xiaosheng Zhou and Maohua Li
Metals 2024, 14(4), 392; https://doi.org/10.3390/met14040392 - 27 Mar 2024
Abstract
A new type of multiphase nanoparticle-reinforced TiAl matrix composites ((Ti2AlC + Al2O3)p/TiAl composites) was successfully prepared by vacuum hot-pressing sintering using Ti powder and Al powder, which were ball-milled with different contents of stearic acid
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A new type of multiphase nanoparticle-reinforced TiAl matrix composites ((Ti2AlC + Al2O3)p/TiAl composites) was successfully prepared by vacuum hot-pressing sintering using Ti powder and Al powder, which were ball-milled with different contents of stearic acid (CH3(CH2)16COOH). The component, microstructure, reaction mechanism, and mechanical properties were studied. The results indicated that the composites prepared by adding stearic acid as a process control agent during the ball-milling process not only contained γ-TiAl and α2-Ti3Al phases but also Ti2AlC and Al2O3 phases. The results of SEM and TEM showed that the composites were composed of equiaxed TiAl and Ti3Al grains, and the Ti2AlC and Al2O3 particles were mainly distributed along the TiAl grain boundary in chain form, which can effectively reduce the TiAl grain size. Through the room-temperature compression test, the maximum compression stress was significantly improved in those composites that added the stearic acid, due to the reinforcement particles. The maximum compression stress was 1590 MPa with a 24.3% fracture strain. In addition, the generated crack deflection and Ti2AlC and Al2O3 particles could also enhance the toughness of the TiAl alloy. (Ti2AlC + Al2O3)p/TiAl composites generated by adding stearic acid played a key role in improving the mechanical properties of the TiAl matrix.
Full article
(This article belongs to the Special Issue Metal Matrix Composites: Fabrication, Mechanical Properties and Application)
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Open AccessArticle
Effect of Nitrogen on the Corrosion Resistance of 6Mo Super Austenitic Stainless Steel
by
Haiyu Tian, Jian Wang, Zhiqiang Liu and Peide Han
Metals 2024, 14(4), 391; https://doi.org/10.3390/met14040391 - 26 Mar 2024
Abstract
6Mo super austenitic stainless steel (SASS) with nitrogen contents of 0.2 and 0.4 (wt.%) was melted, and solution treatments at 1100, 1180, and 1250 °C for 30 min were performed. The effects of nitrogen on the microstructure and pitting resistance of the two
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6Mo super austenitic stainless steel (SASS) with nitrogen contents of 0.2 and 0.4 (wt.%) was melted, and solution treatments at 1100, 1180, and 1250 °C for 30 min were performed. The effects of nitrogen on the microstructure and pitting resistance of the two steels that signed as 0.2N and 0.4N samples were investigated. At a heat-treatment temperature of 1180 °C, the alloy demonstrates the highest corrosion resistance, attributed to the combined effects of grain size and precipitates. The structure of the passivation film changes with increasing nitrogen content, with the Cr/Fe ratio is significantly higher in the 0.4N sample compared to the 0.2N sample. Moreover, the increase in nitrogen content results in thicker Cr and Mo oxide layers and higher levels of NH3 and NH4+, thereby improving the corrosion resistance of the stainless steel.
Full article
(This article belongs to the Special Issue Corrosion Science and Engineering: Recent Research, Insights, and Challenges)
Open AccessArticle
Detection and Imaging of Corrosion Defects in Steel Structures Based on Ultrasonic Digital Image Processing
by
Dazhao Chi, Zhixian Xu and Haichun Liu
Metals 2024, 14(4), 390; https://doi.org/10.3390/met14040390 - 26 Mar 2024
Abstract
Corrosion is one of the critical factors leading to the failure of steel structures. Ultrasonic C-scans are widely used to identify corrosion damage. Limited by the range of C-scans, multiple C-scans are usually required to cover the whole component. Thus, stitching multiple C-scans
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Corrosion is one of the critical factors leading to the failure of steel structures. Ultrasonic C-scans are widely used to identify corrosion damage. Limited by the range of C-scans, multiple C-scans are usually required to cover the whole component. Thus, stitching multiple C-scans into a panoramic image of the area under detection is necessary for interpreting non-destructive testing (NDT) data. In this paper, an image mosaic method for ultrasonic C-scan based on scale invariant feature transform (SIFT) is proposed. Firstly, to improve the success rate of registration, the difference in the probe starting position in two scans is used to filter the matching pairs of feature points obtained by SIFT. Secondly, dynamic programming methods are used to search for the optimal seam path. Finally, the pixels in the overlapping area are fused by fade-in and fade-out fusion along the seam line. The improved method has a higher success rate of registration and lower image distortion than the conventional method in the mosaic of ultrasonic C-scan images. Experimental results show that the proposed method can stitch multiple C-scan images of a testing block containing artificial defects into a panorama image effectively.
Full article
(This article belongs to the Special Issue Corrosion Protection for Metallic Materials)
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Open AccessArticle
Effects of Annealing Temperature on Microstructural Evolution and Mechanical Properties in Cold-Rolled High-Nitrogen Austenitic Steel
by
Jong-Ho Shin, Jeon-Young Song and Young-Wha Ma
Metals 2024, 14(4), 389; https://doi.org/10.3390/met14040389 - 26 Mar 2024
Abstract
High-nitrogen austenitic steel (HNS) cold-rolled with a reduction rate of 25% was subjected to an investigation of the effect of annealing temperature on microstructural evolution, tensile properties and the variation in fracture surface morphology. In cold-rolled HNS, matrix recovery occurred at an annealing
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High-nitrogen austenitic steel (HNS) cold-rolled with a reduction rate of 25% was subjected to an investigation of the effect of annealing temperature on microstructural evolution, tensile properties and the variation in fracture surface morphology. In cold-rolled HNS, matrix recovery occurred at an annealing temperature of 600 °C, and recrystallization was locally initiated at an annealing temperature of 800 °C. The 0.2% offset yield strength (0.2% YS) and ultimate tensile strength (UTS) were almost constant up to an annealing temperature of 500 °C, and these values gradually decreased above the annealing temperature of 600 °C, while a sharp reduction in the percentage reduction in area (RA) occurred at the annealing temperatures of 600 and 700 °C due to Cr2N precipitation along the grain and twin boundaries. The ratio of 0.2% offset yield strength to ultimate tensile strength (0.2% YS/UTS) remained constant until matrix recovery took place; however, once recrystallization occurred, the ratio decreased significantly. Furthermore, the variation in the morphology of Cr2N along the grain boundaries in the annealing temperature range from 600 to 800 °C influenced the intergranular fracture morphology, resulting in a transition from dimple to ledge and back to dimple.
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(This article belongs to the Section Metal Casting, Forming and Heat Treatment)
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Open AccessArticle
Corrosion of API 5L X60 Pipeline Steel in Soil and Surface Defects Detection by Ultrasonic Analysis
by
Fatima Benkhedda, Ismail Bensaid, Abderrahim Benmoussat, Sid Ahmed Benmansour and Abdeldjelil Amara Zenati
Metals 2024, 14(4), 388; https://doi.org/10.3390/met14040388 - 26 Mar 2024
Abstract
The corrosion steels phenomenon is one of the main problems in the oil industry, such as in buried transmission pipelines used for high gas pressure for long distances. Steels are protected from the external soil corrosion through a bituminous coating, whose action is
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The corrosion steels phenomenon is one of the main problems in the oil industry, such as in buried transmission pipelines used for high gas pressure for long distances. Steels are protected from the external soil corrosion through a bituminous coating, whose action is coupled with a cathodic protection system, which aims to maintain steel in its protection field and thus to avoid any corrosion risk. However, steels in service may experience external surface defects like corrosion pitting and cracking due to electrochemical or mechanical interactions of bare steel with an aggressive soil solution after steel protection failure. These are concerning phenomena and are the major threats of the pipeline transmission system’s reliability and ecological safety. Corrosion mechanisms are varied and can be evaluated by different methods, such as electrochemical measurements, which are influenced by various factors like temperature, pH, soil characteristics, resistivity, water content, and as well mechanical stresses. Corrosion results from simulated artificial soil solutions showed that steel is sensitive to corrosion by soil. Surface defects detection was carried out using an ultrasonic non-destructive method such as C-Scan Emission testing and the time of flight diffraction technique (TOFD) ultrasonic non-contact testing method. After propagation of the ultrasonic waves, the diffracted ultrasonic reflected wave occurring at the edges of the defects appears due to the presence of a corrosion defect by generating defect echoes. The C-Scan ultrasonic image shows surface reflection, including corrosion defects on interfaces with varying acoustic impedances. The cross-transverse speed ultrasonic propagation through the plate including defect is modified, revealing more surface defects, and cross-transverse speed is shown to increase ultrasonic detection presents some advantages, such as precision and speed of detection without alteration to the structure. This method can be used in the industrial context as an intelligent industrial robotics technique.
Full article
(This article belongs to the Special Issue Environmentally-Assisted Degradation of Metals and Alloys)
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Open AccessFeature PaperArticle
Introducing Auxetic Behavior to Syntactic Foams
by
Nejc Novak, Miha Kolar, Nima Movahedi, Matej Vesenjak, Zoran Ren and Thomas Fiedler
Metals 2024, 14(4), 387; https://doi.org/10.3390/met14040387 - 26 Mar 2024
Abstract
This paper proposes an innovative multi-material approach for introducing auxetic behaviour to syntactic foams (SFs). By carefully designing the size, shape, and orientation of the SFs, auxetic deformation behaviour was induced. Re-entrant hexagon-shaped SF elements were fabricated using expanded perlite (EP) particles and
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This paper proposes an innovative multi-material approach for introducing auxetic behaviour to syntactic foams (SFs). By carefully designing the size, shape, and orientation of the SFs, auxetic deformation behaviour was induced. Re-entrant hexagon-shaped SF elements were fabricated using expanded perlite (EP) particles and a plaster of Paris slurry first. Then, an auxetic pattern of these SF elements was arranged within a stainless-steel casting box. The empty spaces between the SF elements were filled with molten aluminium alloy (A356) using the counter-gravity infiltration casting technique. The cast auxetic composite had a bulk density of 1.52 g/cm3. The cast composite was then compressed under quasi-static loading to characterise its deformation behaviour and to determine the mechanical properties, especially the Poisson’s ratio. The cast composite deformation was auxetic with a Poisson’s ratio of −1.04. Finite Element (FE) simulations were conducted to understand the deformation mechanism better and provide means for further optimisation of the geometry.
Full article
(This article belongs to the Special Issue Metal-Based Composite Materials: Properties, Synthesis, Prospects and Challenges)
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Open AccessArticle
Effect of Copper Content on the Microstructure and Properties of the Sintered Porous Aluminum Wick
by
Yanbo Cai and Bohua Duan
Metals 2024, 14(4), 386; https://doi.org/10.3390/met14040386 - 26 Mar 2024
Abstract
Porous aluminum has been widely used as a wick, an electrode, and in other products, due to its advantages of a light weight, pore uniformity, and corrosion resistance. However, the dense alumina layer on the surface of Al powder hinders its densification during
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Porous aluminum has been widely used as a wick, an electrode, and in other products, due to its advantages of a light weight, pore uniformity, and corrosion resistance. However, the dense alumina layer on the surface of Al powder hinders its densification during sintering. In this paper, porous aluminum was prepared via loose powder sintering with the addition of Cu as a sintering aid. The effects of Cu content on the microstructure and wick properties of the porous aluminum were investigated. The results showed that, with increasing Cu content, the porosity and capillary properties of porous Al decreased, while the compressive strength improved. The optimal Cu content was determined to be 3 wt.% and the prepared porous Al has a porosity of 47.5%, plateau stress of 11.82 MPa, and capillary characteristic parameter of 6.72 × 10−8 N, meeting the requirements for wicks in heat pipes. These findings contribute to the demand for the lightweight design of heat pipes for aerospace applications.
Full article
(This article belongs to the Special Issue High-Performance Powder Metallurgy Structural Materials)
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Open AccessArticle
Structure, Microstructure and Magnetocaloric/Thermomagnetic Properties at the Early Sintering of MnFe(P,Si,B) Compounds
by
Tvrgvn Qianbai, Hargen Yibole and Francois Guillou
Metals 2024, 14(4), 385; https://doi.org/10.3390/met14040385 - 26 Mar 2024
Abstract
Minimizing the sintering time while ensuring high performances is an important optimization step for the preparation of magnetocaloric or thermomagnetic materials produced by powder metallurgy. Here, we study the influence of sintering time on the properties of a Mn0.95Fe1P
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Minimizing the sintering time while ensuring high performances is an important optimization step for the preparation of magnetocaloric or thermomagnetic materials produced by powder metallurgy. Here, we study the influence of sintering time on the properties of a Mn0.95Fe1P0.56Si0.39B0.05 compound. In contrast to former reports investigating different annealing temperatures during heat treatments of several hours or days, we pay special attention to the earliest stages of sintering. After ball-milling and powder compaction, 2 min sintering at 1100 °C is found sufficient to form the desired Fe2P-type phase. Increasing the sintering time leads to a sharper first-order magnetic transition, a stronger latent heat, and usually to a larger isothermal entropy change, though not in all cases. As demonstrated by DSC or magnetization measurements, these parameters present dissimilar time evolutions, highlighting the existence of various underlying mechanisms. Chemical inhomogeneities are likely responsible for broadened transitions for the shortest sinterings. The development of strong latent heat requires longer sinterings than those for sharpening the magnetic transition. The microstructure may play a role as the average grain size progressively increases with the sintering time from 3.5 μm (2 min) to 30.1 μm (100 h). This systematic study has practical consequences for optimizing the preparation of MnFe(P,Si,B) compounds, but also raises intriguing questions on the influence of the microstructure and of the chemical homogeneity on magnetocaloric or thermomagnetic performances.
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(This article belongs to the Special Issue Feature Papers in Metallic Functional Materials)
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Open AccessArticle
Ultrasound-Assisted Synthesis of High-Entropy Materials for Enhanced Oxygen Evolution Electrocatalysis
by
Zhiyuan Wang, Chengxu Zhang, Yue Zhang and Jue Hu
Metals 2024, 14(4), 384; https://doi.org/10.3390/met14040384 - 25 Mar 2024
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High-entropy materials (HEMs) play a significant role in the electrocatalytic oxygen evolution reaction (OER) due to their unique properties. However, there are still challenges in the preparation of HEMs for OER catalysts. In this study, the FeCoNiMnCr catalyst is synthesized for the first
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High-entropy materials (HEMs) play a significant role in the electrocatalytic oxygen evolution reaction (OER) due to their unique properties. However, there are still challenges in the preparation of HEMs for OER catalysts. In this study, the FeCoNiMnCr catalyst is synthesized for the first time using the ultrasonic hydrothermal-sintering technique and exhibits excellent performance for OER electrocatalysis. There is an optimal ultrasonic hydrothermal time and power for achieving the best OER performance. The results demonstrate that the performance of FeCoNiMnCr catalysts prepared through ultrasonic hydrothermal sintering (US-FeCoNiMnCr) is significantly improved compared with the traditional hydrothermal-sintering method. The US-FeCoNiMnCr catalyst exhibits an overpotential of 228 mV at the current density of 10 mA cm−2 and a Tafel slope as low as 45.39 mV dec−1 in an alkaline medium. Moreover, the US-FeCoNiMnCr catalyst demonstrates remarkable stability in electrocatalytic OER with a minimal potential increase observed even after 48 h. This work not only provides valuable insights into high-entropy material synthesis, but also presents a powerful electrocatalyst for water electrolysis.
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Open AccessArticle
Experimental Investigation of the Three-Point Bending Property of a Sandwich Panel with a Metal Rubber Core
by
Wei Zhang, Shanshan Wang, Xiaoyuan Zheng and Xin Xue
Metals 2024, 14(4), 383; https://doi.org/10.3390/met14040383 - 25 Mar 2024
Abstract
Sandwich structures and porous materials have been applied widely in various fields due to their excellent mechanical performance, and multifunctional composites will have a significant engineering demand in the future. Studying damped composites’ mechanical properties and failure forms has significant engineering value and
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Sandwich structures and porous materials have been applied widely in various fields due to their excellent mechanical performance, and multifunctional composites will have a significant engineering demand in the future. Studying damped composites’ mechanical properties and failure forms has significant engineering value and significance. However, the current connecting processes for sandwich panels and porous materials must be improved. Therefore, to explore the ambiguity of the connection interface between the core material and panel in sandwich panels, as well as the mechanical properties of such structures, a sandwich panel with a metal rubber core material was prepared using vacuum brazing and cementing processes. Microscopic examinations using scanning electron microscopy and energy-dispersive spectroscopy were conducted to observe the physical bonding mechanism at the interface of the sandwich panel. The results indicate that the brazed sandwich panels exhibited a more uniform and continuous interface than the cemented sandwich panels. This work designs three-point bending compression experiments to investigate the effects of core material thickness, density, and preparation process on the bending mechanical properties of the sandwich panel. Failure modes of the sandwich panel during the experiments are analyzed. The experimental results show that the failures of the brazed sandwich panels are attributable to the bending deformation of the panel and the shear failure of the metal wire core material. The cemented sandwich panels exhibit separation failures in the area below the indenter and at both ends of the panel. The core material’s thickness and density significantly influence the bending performance of the sandwich panels. An increase in the core material’s thickness and density effectively enhances the sandwich panels’ peak load and energy absorption capacity.
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(This article belongs to the Special Issue Modeling, Testing and Applications of Metallic Foams and Cellular Materials)
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The Influence of Groove Geometry on the Creep Fracture Behavior of Dissimilar Metal Welds between Ferritic Heat-Resistant Steels and Nickel-Based Alloys
by
Tengfei Zhang, Qu Liu, Xiaogang Li, Kejian Li and Zhipeng Cai
Metals 2024, 14(4), 382; https://doi.org/10.3390/met14040382 - 25 Mar 2024
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This study investigates the influence of groove geometry on the high-temperature creep life and fracture behavior of Dissimilar Metal Welds (DMWs) between low-alloy steel 2.25Cr1Mo and austenitic stainless steel 347H using Inconel 82 nickel-based filling metal. This research aims to reveal the effect
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This study investigates the influence of groove geometry on the high-temperature creep life and fracture behavior of Dissimilar Metal Welds (DMWs) between low-alloy steel 2.25Cr1Mo and austenitic stainless steel 347H using Inconel 82 nickel-based filling metal. This research aims to reveal the effect of groove geometry, especially the stepped groove, on creep crack propagation path and creep life, through a combined approach of finite element simulation considering stress triaxiality and experimental validation. The study reveals that the stepped groove alters the creep crack propagation path, enhancing the endurance life by deflecting cracks away from the weld/heat-affected zone (HAZ) interface and directing them into regions with higher creep resistance. The experimental results verify the simulation findings, revealing that the stepped groove joints exhibited longer creep life with changes in failure location and mechanism compared to the V-groove joints. However, it was found that the stepped groove intensified the stress concentration at the early creep stage. Thus, a good balance should be achieved between the negative (stress concentration at interface) and positive (changing crack paths) effects of the stepped groove to extend the creep life of DMWs.
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Open AccessArticle
Fretting Fatigue Life Prediction for Aluminum Alloy Based on Particle-Swarm-Optimized Back Propagation Neural Network
by
Xin Li, Haoran Yang and Jianwei Yang
Metals 2024, 14(4), 381; https://doi.org/10.3390/met14040381 - 25 Mar 2024
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Fretting fatigue is a specific fatigue phenomenon. Due to the complex mechanisms and multitude of influencing factors, it is still hard to predict fretting fatigue life accurately, despite there being many works on this topic. This paper developed a particle-swarm-optimized back propagation neural
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Fretting fatigue is a specific fatigue phenomenon. Due to the complex mechanisms and multitude of influencing factors, it is still hard to predict fretting fatigue life accurately, despite there being many works on this topic. This paper developed a particle-swarm-optimized back propagation neural network to predict the fretting fatigue life of aluminum alloys using the test data gathered from the published literature. A commonly used critical plane model, the Smith, Watson, and Topper criterion, was used as a contrast. The analysis result shows that the proposed fretting fatigue life prediction neural network model achieves a higher prediction accuracy compared to the traditional SWT model. Experimental validation demonstrates the effectiveness of the model in improving the accuracy of fretting fatigue life prediction. This research provides a new data-driven methodology for fretting fatigue life prediction.
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Open AccessArticle
Evolution of Microstructure, Properties, and Fracture Behavior with Annealing Temperature in Complex Phase Steel with High Formability
by
Xiaohong Chu, Feng Zhou, Lei Liu, Xiaolong Xu, Xiaoyue Ma, Weinan Li and Zhengzhi Zhao
Metals 2024, 14(4), 380; https://doi.org/10.3390/met14040380 - 25 Mar 2024
Abstract
In recent years, with the continuous improvement in the requirements for automobile steel formability, complex phase steel with high formability (CH steel) has been widely used. In the present study, the microstructure of CH steel was regulated using the actual production process as
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In recent years, with the continuous improvement in the requirements for automobile steel formability, complex phase steel with high formability (CH steel) has been widely used. In the present study, the microstructure of CH steel was regulated using the actual production process as a basis and annealing temperature as a variable, and the effects of annealing temperature on the microstructure, properties, and fracture behavior of CH steel were analyzed. As the annealing temperature increases, the ferrite content decreases from 36.3% to 0, the martensite content decreases from 49.3% to 8.8%, the bainite content increases from 11.9% to 87.1%, and the retained austenite content first increases and then decreases within the range of 2.5~5.1%. Consequently, the tensile strength shows a decreasing trend, the yield strength first decreases and then increases, and the total elongation and the hole expansion ratio first increase and then decrease. The deformation coordination of each phase gradually becomes better, and the voids and cracks in the tensile and hole expansion samples expand along the ferrite and martensite or martensite/austenite (M/A) island interface, transforming into the bainitic ferrite and martensite or M/A islands. The test steel’s best tensile and hole expansion properties occur at annealing temperatures of 940 °C.
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(This article belongs to the Special Issue Development of Advanced High-Strength Steels)
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Open AccessArticle
Synthesis of TiCx/Al Composites via In Situ Reaction between AlxTi Melt and Dissolvable Solid Carbon
by
Lei Guo, Hao Sun and Zhancheng Guo
Metals 2024, 14(4), 379; https://doi.org/10.3390/met14040379 - 24 Mar 2024
Abstract
TiCx/Al composites were successfully prepared in this study by dissolving graphite particles in Al-Ti melt based on the principle of a solid–liquid in situ reaction. It was observed that the microstructure of the TiCx/Al composites changed with changes in
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TiCx/Al composites were successfully prepared in this study by dissolving graphite particles in Al-Ti melt based on the principle of a solid–liquid in situ reaction. It was observed that the microstructure of the TiCx/Al composites changed with changes in the reaction temperature and graphite particle size. With an increase in reaction temperature, the TiCx particles in the TiCx/Al composites transitioned from a spider-like distribution to being evenly dispersed in the Al matrix. Additionally, the morphology of the TiCx particles changed from polygons of various sizes to quasi-spherical shapes with a uniform particle size, while the presence of Al4C3 and Al3Ti in the matrix diminished. The size variation of the graphite particles had minimal impact on the particle size and stoichiometric ratio of TiCx generated in the sample. Furthermore, an appropriate graphite particle size was found to mitigate the agglomeration and residue of graphite particles during the in situ reaction.
Full article
(This article belongs to the Special Issue Metal Matrix Composites Reinforced with Carbon Nanomaterials)
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Open AccessArticle
Buckling Defect Optimization of Constrained Ring Rolling of Thin-Walled Conical Rings with Inner High Ribs Combining Response Surface Method with FEM
by
Wei Feng and Peng Zhao
Metals 2024, 14(4), 378; https://doi.org/10.3390/met14040378 - 24 Mar 2024
Abstract
A buckling defect will appear on the outer surface of the deformed ring during the constrained ring rolling (CRR) of an aluminum alloy thin-wall conical ring with inner high ribs (AATWCRIHR) if the geometrical dimension of the ribs does not match the wall
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A buckling defect will appear on the outer surface of the deformed ring during the constrained ring rolling (CRR) of an aluminum alloy thin-wall conical ring with inner high ribs (AATWCRIHR) if the geometrical dimension of the ribs does not match the wall thickness. To avoid the buckling defect, a quantitative method for characterizing the degree of the buckling defect is proposed using the area of the buckling profile. Then, an orthogonal experimental scheme was designed, taking the width of the middle rib, thickness of wall, and height of the middle rib as the design variables and defining the area of the buckling profile as the optimization objective. Subsequently, a quadratic polynomial response surface model was established by combining the optimization algorithm with the finite element method (FEM), and the geometrical dimension of the middle ribs of the deformed AATWCRIHR is optimized. Moreover, the optimal parameter combination to minimize the area of the buckling profile is obtained and verified using FE simulation. The results show that the AATWCRIHR after optimization does not generate the buckling defect during constrained ring rolling, and it is proven that the quantitative buckling defect representation method and the optimization design method based on the response surface model and the finite element simulation results are feasible for the constrained ring-rolling process of the AATWCRIHR.
Full article
(This article belongs to the Special Issue Advanced Rolling, Heat Treatment and Electromagnetic Processing Technology of High Performance Metals (Second Edition))
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Open AccessArticle
Numerical Study on the Heat Transfer of Confined Air-Jet Quenching of Steel Sheets
by
Yanqi Ye, Tianliang Fu, Guanghao Liu and Guodong Wang
Metals 2024, 14(4), 377; https://doi.org/10.3390/met14040377 - 24 Mar 2024
Abstract
The high flatness quenching of ultra-high-strength steel sheets is a technical problem in the steel industry. In this study, the traditional water and spray quenching methods were abandoned, and the roller-constrained slot air-jet quenching method was proposed for steel sheets below 3 mm
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The high flatness quenching of ultra-high-strength steel sheets is a technical problem in the steel industry. In this study, the traditional water and spray quenching methods were abandoned, and the roller-constrained slot air-jet quenching method was proposed for steel sheets below 3 mm thickness, which provided a theoretical reference for producing thinner, wider, and higher-flatness steel sheets. A 2D roller-constrained slot air-jet numerical model was established to study the flow field and heat transfer characteristics under the conditions of Reynolds number 24,644–41,076, a dimensionless jet height of 16–24, and a jet angle of 45°–135°. The results showed that the average Nusselt number on the heat transfer surface was proportional to Rem. At the same time, high-intensity heat transfer was achieved when the dimensionless height and jet angle were properly combined. At the same Reynolds number, the heat transfer intensity could be increased by 289%. In addition, the position of the peak Nusselt number was affected by reducing the jet angle, which served as an effective strategy for adjusting the martensite ratio and obtaining ideal mechanical properties.
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(This article belongs to the Special Issue Metal Rolling and Heat Treatment Processing)
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Corrosion Behavior of Carbon Steel in LiCl/H2O Mixtures
by
Modesto Avilés-Flores, Ana Karen Larios-Gálvez, José Martínez-González, Roy Lopez-Sesenes, Alfredo Brito-Franco, Jesús Cerezo, Francisco Christian Martinez Tejeda, America Maria Ramirez-Arteaga and Jose Gonzalo Gonzalez-Rodriguez
Metals 2024, 14(4), 376; https://doi.org/10.3390/met14040376 - 23 Mar 2024
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The corrosion behavior of 1018 carbon steel in LiCl/H2O mixtures has been evaluated by using potentiodynamic polarization curves, electrochemical noise and electrochemical impedance spectroscopy techniques. Two different concentrations of LiCl were employed, namely 35 and 40 wt. %, and the testing
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The corrosion behavior of 1018 carbon steel in LiCl/H2O mixtures has been evaluated by using potentiodynamic polarization curves, electrochemical noise and electrochemical impedance spectroscopy techniques. Two different concentrations of LiCl were employed, namely 35 and 40 wt. %, and the testing temperatures included 25, 35 and 70 °C. It was found that the steel showed a passive zone; the corrosion current density value increased with an increase in the solution temperature and concentration. The pitting potential value decreased with an increase in the testing temperature and the solution concentration. The corrosion process was under charge transfer control. This mechanism was unaltered either by the solution temperature or concentration. The charge transfer resistance value decreased with an increase in both the solution temperature and concentration. A localized, pitting type of corrosion dominated the corrosion morphology at 25 and 35 °C, whereas at 70 °C, the main type of attack was a mixed type of corrosion.
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Effect of Aging Temperature on Microstructure, Mechanical, and Wear Properties of 18Ni-300 Maraging Steel Produced by Powder Bed Fusion
by
Nawon Kwak, Yujin Lim, Seokha Heo, Chami Jeon and Ilguk Jo
Metals 2024, 14(4), 375; https://doi.org/10.3390/met14040375 - 23 Mar 2024
Abstract
Additive manufacturing technologies for metallic materials based on powder bed fusion have enormous industrial potential. In this study, we manufactured 18Ni-300 maraging steel using the powder bed fusion (PBF) process and investigated the effects of annealing temperatures of 430 °C, 490 °C, and
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Additive manufacturing technologies for metallic materials based on powder bed fusion have enormous industrial potential. In this study, we manufactured 18Ni-300 maraging steel using the powder bed fusion (PBF) process and investigated the effects of annealing temperatures of 430 °C, 490 °C, and 550 °C for 3 h on its microstructure, tensile fracture mechanism, and wear properties compared with the as-built specimen. The results show that annealing heat treatment effectively improved the dry sliding friction, wear properties, and room temperature tensile properties compared to the as-built specimen. Compared to other aging-treated samples, specimens that underwent heat treatment in optimal settings had superior properties. With optimal heat treatment, while melt pool boundaries remained, the cellular and columnar structures became finer compared to the un-treated specimens, and the number of dimples decreased. Consequently, the hardness and tensile strength improved by approximately 56.17% and 40.63%, respectively. The 18Ni-300 maraging steel sample that underwent heat treatment at optimal settings exhibited a coefficient of friction approximately 33.33% lower than the as-built alloy.
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(This article belongs to the Special Issue Microstructure and Properties of Alloys Manufactured by Selective Laser Melting)
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Microstructural and Mechanical Characterization of Low-Alloy Fire- and Seismic-Resistant H-Section Steel
by
Jinhyuk Kim, Gyeongsik Yu, Sangeun Kim, Jinwoo Park, Minkyu Ahn, Jun-Ho Chung, Chang-Hoon Lee and Chansun Shin
Metals 2024, 14(4), 374; https://doi.org/10.3390/met14040374 - 23 Mar 2024
Abstract
This study investigates the microstructure and nano-hardness distribution across the thickness of an H-section steel beam, specifically designed for seismic and fire resistance and fabricated using a quenching and self-tempering process. The beam dimensions include a 24 mm thick flange, with flange and
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This study investigates the microstructure and nano-hardness distribution across the thickness of an H-section steel beam, specifically designed for seismic and fire resistance and fabricated using a quenching and self-tempering process. The beam dimensions include a 24 mm thick flange, with flange and web lengths of 300 mm and 700 mm, respectively. Our findings indicate that the mechanical properties across the flange thickness meet the designed criteria, with yield strengths exceeding 420 MPa, tensile strengths of over 520 MPa, and a yield-to-tensile strength ratio below 0.75. Microstructurally, the central part of the flange predominantly consists of granular bainite with a small fraction of martensite–austenite (MA) constituents, while locations closer to the surface show increased acicular ferrite and decreased MA constituents due to faster cooling rates. Furthermore, thermal exposure at 600 °C reveals that while the matrix microstructure remains thermally stable, the MA phase undergoes tempering, leading to a decrease in nano-hardness. These insights underline the significant impact of MA constituents on the elongation properties and stress concentrations, contributing to the overall understanding of the material’s behavior under seismic and fire conditions. The study’s findings are crucial for enhancing the reliability and safety of construction materials in demanding environments.
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(This article belongs to the Special Issue Phase Transformation and Microstructure Characterization in Steels)
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