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Volume 14
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Metals, Volume 14, Issue 10 (October 2024) – 16 articles

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10 pages, 994 KiB  
Article
Effect of Electrical Parameters on the Structure and Properties of Aluminum Foil Microarc Oxidation Film
by Haoren Li, Yong Huang, Qingyu Meng and Xun Wang
Metals 2024, 14(10), 1108; https://doi.org/10.3390/met14101108 (registering DOI) - 26 Sep 2024
Abstract
Through a three-factor, two-level orthogonal experiment, the effects of varying electrical parameters (voltage, frequency, and duty cycle) on the thickness, pressure resistance, corrosion resistance, morphology, and phase composition of the micro-arc oxidized film of aluminum foil in constant voltage mode were investigated. The [...] Read more.
Through a three-factor, two-level orthogonal experiment, the effects of varying electrical parameters (voltage, frequency, and duty cycle) on the thickness, pressure resistance, corrosion resistance, morphology, and phase composition of the micro-arc oxidized film of aluminum foil in constant voltage mode were investigated. The aluminum foil was oxidized by micro-arc oxidation for 50 min. Eddy-current thickness gauges were used to measure the oxide film’s thickness, TV characterization testers were used to test the film’s resistance to pressure, kinetic potential polarization curves were used to examine the oxide film’s resistance to electrochemical corrosion, and SEM and XRD composition were used to examine the microstructures and phase compositions of the oxide films that were produced. The oxide film’s thickness was increased from 7 μm to 22 μm and the voltage was increased from 350 V to 450 V. The oxide film’s ramp-up time at a frequency and duty cycle of 2000 Hz and 15% could reach 3 s, and the resistance value could reach 98% of the micro-arc oxidation voltage. The oxide film’s icorr decreased by an order of magnitude at high voltage compared to low voltage and the Rp value increased by an order of magnitude, which improved the corrosion resistance. The oxide film’s thickness increased as the voltage increased. Meanwhile, SEM was used to enhance the corrosion resistance. The oxide film thickens as the voltage increases. At the same voltage, the oxide film with a high frequency and low duty cycle has the best voltage resistance. The oxide film generated under high-voltage conditions has regular and dense surface holes, the oxide film’s α-Al2O3 phase increases, and the corrosion resistance in the NaCl medium is enhanced. Full article
14 pages, 1267 KiB  
Article
The Interfacial Reaction between Amorphous Ni-W-P Coating and Sn-58Bi Solder
by Chenyu Li, Xiaolin Su, Zhongxu Zhang, Haitao Ma, Jinye Yao, Haohao Xia and Yuanbang Zhao
Metals 2024, 14(10), 1107; https://doi.org/10.3390/met14101107 - 26 Sep 2024
Abstract
With the rapid development of the advanced electronic packaging field, the requirements for the connection between solder and Cu substrate are becoming increasingly stringent. Currently, the commonly used Ni-P diffusion barrier layer in the industry lacks long-term reliability, and its resistivity is higher [...] Read more.
With the rapid development of the advanced electronic packaging field, the requirements for the connection between solder and Cu substrate are becoming increasingly stringent. Currently, the commonly used Ni-P diffusion barrier layer in the industry lacks long-term reliability, and its resistivity is higher than that of other substrates. This paper introduces the highly conductive metal element W to modify the binary Ni-P coating and prepares a ternary Ni-W-P coating through electrodeposition to improve this situation. The key parameters for the electrodeposition of ternary Ni-W-P are determined. The isothermal aging reaction of Ni-W-P with Sn-Bi solder at 100 °C was studied, and the results showed that, compared to the conventional Ni-P coating, the Ni-W-P barrier coating with higher W content has a much longer lifespan as a barrier layer and exhibits significantly better electrical conductivity. Additionally, the reaction mechanism between Ni-W-P and the Sn-Bi solder is proposed. This research presents a promising advancement in the development of barrier layers for electronic packaging, potentially leading to more reliable and efficient electronic devices. Introducing tungsten into the Ni-P matrix not only extends the lifespan of the coating but also enhances its electrical performance, making it a valuable innovation for applications requiring high conductivity and durability. This study could guide further investigations into the application of ternary coatings in various electronic components, paving the way for improved designs and materials in the semiconductor industry. Full article
21 pages, 41273 KiB  
Article
Statistical Analysis-Based Prediction Model for Fatigue Characteristics in Lap Joints Considering Weld Geometry, Including Gaps
by Dong-Yoon Kim and Jiyoung Yu
Metals 2024, 14(10), 1106; https://doi.org/10.3390/met14101106 - 26 Sep 2024
Abstract
Automotive chassis components, constructed as lap joints and produced by gas metal arc welding (GMAW), require fatigue durability. The fatigue properties of the weld in a lap joint are largely determined by weld geometry factors. When there is no gap or a consistent [...] Read more.
Automotive chassis components, constructed as lap joints and produced by gas metal arc welding (GMAW), require fatigue durability. The fatigue properties of the weld in a lap joint are largely determined by weld geometry factors. When there is no gap or a consistent gap in the lap joint, improving the geometry of the weld toe can alleviate stress concentration and enhance fatigue properties. However, due to machining tolerances, it is difficult to completely eliminate or consistently manage the gap in the joint. In the case of a lap-welded joint with an inconsistent gap, it is necessary to identify the weld geometry factors related to fatigue properties. Evaluating the fatigue behavior of materials and welded joints requires significant time and cost, meaning that research that seeks to predict fatigue properties is essential. More research is needed on predicting fatigue properties related to automotive chassis components, particularly studies on predicting the fatigue properties of lap-welded joints with gaps. This study proposed a regression model for predicting fatigue properties based on crucial weld geometry factors in lap-welded joints with gaps using statistical analysis. Welding conditions were varied in order to build various weld geometries in joints configured in a lap with gaps of 0, 0.2, 0.5, and 1.0 mm, and 87 S–N curves for the lap-welded joints were derived. As input variables, 17 weld geometry factors (7 lengths, 7 angles, and 3 area factors) were selected. The slope of the S–N curve using the Basquin model from the S–N curve and the safe fatigue strength were selected as output variables for prediction in order to develop the regression model. Multiple linear regression models, multiple non-linear regression models, and second-order polynomial regression models were proposed to predict fatigue properties. Backward elimination was applied to simplify the models and reduce overfitting. Among the three proposed regression models, the multiple non-linear regression model had a coefficient of determination greater than 0.86. In lap-welded joints with gaps, the weld geometry factors representing fatigue properties were identified through standardized regression coefficients, and four weld geometry factors related to stress concentration were proposed. Full article
(This article belongs to the Special Issue Advances in Welding Processes of Metallic Materials)
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16 pages, 25268 KiB  
Article
Microstructure and Characteristics of the Welded Joint between Ni-Cr Alloys and Copper
by Jingang Zhang, Wanpeng Zhang, Xiaoquan Yu, Hang Xie, Chao Zhou, Hongbing Song and Jiankang Huang
Metals 2024, 14(10), 1105; https://doi.org/10.3390/met14101105 - 26 Sep 2024
Abstract
In the field of petroleum extraction, the welding technology of the core wire (the hybrid structure of copper and the Ni-Cr alloy) in high-power oilfield heaters is a key process that determines the efficiency of the heater. Using the tungsten inert gas (TIG) [...] Read more.
In the field of petroleum extraction, the welding technology of the core wire (the hybrid structure of copper and the Ni-Cr alloy) in high-power oilfield heaters is a key process that determines the efficiency of the heater. Using the tungsten inert gas (TIG) welding method of filling pure copper wire, this work effectively joins the dissimilar metals of red copper and the Cr20Ni80 nickel–chromium alloy. The microstructure, mechanical properties, and conductivity of the joint were analyzed. The results showed that the surface of the welded dissimilar metal joint was smooth and uniform; radiographic nondestructive testing did not reveal any macroscopic forming defects such as pores or cracks. The microstructure of the joint fusion zone exhibits an equiaxed grain morphology. The interface between the copper and the fusion zone displays a columnar grain structure, growing perpendicular to the fusion line. An interdiffusion layer of elements was formed at the interface between the Ni-Cr alloy and the fusion zone. The microhardness of the joint shows a stepwise decreasing trend, with the highest hardness on the nickel–chromium alloy side, followed by the fusion zone, and the lowest on the copper side. The joint fractures at the copper base material, with a tensile strength greater than 220 MPa, indicating a ductile fracture mode. During the electrical heating process, the joint temperature does not significantly increase compared to the copper side, demonstrating good thermal stability. Full article
(This article belongs to the Special Issue New Technology of Welding/Joining of Metallic Materials)
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19 pages, 10590 KiB  
Article
Miniature Tensile and Small Punch Testing: Mechanical Performance and Application in Hydrogen Embrittlement Analysis
by Ping Tao, Wei Zhou, Xinting Miao, Jian Peng and Xuedong Liu
Metals 2024, 14(10), 1104; https://doi.org/10.3390/met14101104 - 26 Sep 2024
Abstract
The utilization of micro-sample testing has demonstrated its effectiveness in conducting quantitative research on mechanical properties, damage evolutions and fracture features. For in-service equipment, millimicron sampling allows for non-destructive testing and analysis of mechanical performance evolution during operation. This paper presents a comparative [...] Read more.
The utilization of micro-sample testing has demonstrated its effectiveness in conducting quantitative research on mechanical properties, damage evolutions and fracture features. For in-service equipment, millimicron sampling allows for non-destructive testing and analysis of mechanical performance evolution during operation. This paper presents a comparative study of the miniature uniaxial tensile test (MUTT) and small punch test (SPT) by experimental and finite element methods. As a comparison, the standard conventional-size tensile tests were also carried out. Detailed analyses of the elastoplastic behaviors and damage evolutions of MUTT and SPT were presented, followed by an application case illustrating the characterization of hydrogen embrittlement sensitivity based on MUTT and SPT. An inverse finite element modeling method of load–displacement curve reproduction was used to calibrate the variations of damage parameters of hydrogen-charged MUTT and SPT specimens. Hydrogen embrittlement (HE) indexes were determined by using different calculation methods. The results reveal that the HE sensitivity estimated by MUTT is higher than that measured by SPT, which is related to the different deformation processes and strain rates of the two testing methods. Full article
(This article belongs to the Special Issue Modeling, Simulation and Experimental Studies in Metal Forming)
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23 pages, 8690 KiB  
Article
The Triaxiality Effect on Damage Evolution in Al-2024 Tensile Samples
by Álvaro González, Diego Celentano, Marcela Cruchaga and Jean-Philippe Ponthot
Metals 2024, 14(10), 1103; https://doi.org/10.3390/met14101103 - 26 Sep 2024
Abstract
The effect of triaxiality on the evolution of damage in Al-2024 aluminum cylindrical specimens is studied in this work. Uncoupled and coupled damage models, all of them explicitly dependent on triaxiality, are assessed and compared. These models are characterized by tensile tests on [...] Read more.
The effect of triaxiality on the evolution of damage in Al-2024 aluminum cylindrical specimens is studied in this work. Uncoupled and coupled damage models, all of them explicitly dependent on triaxiality, are assessed and compared. These models are characterized by tensile tests on cylindrical specimens without notches, to obtain the material parameters for each model. The capability of each model to predict fracture when different positive triaxial conditions evolve is then evaluated through tensile tests on notched cylindrical specimens. In particular, the damage index, evaluated at the fracture strain level, is compared with the experimental results validating the models. Moreover, the triaxiality evolution in the different specimens is studied in order to assess its effect on damage, demonstrating that the fracture strain decreases at greater triaxiality values. Observations through scanning electron microscopy confirm this pattern; i.e., an increase in triaxiality reveals a shift in the fracture mechanism from a more ductile condition in the original specimens to a more brittle one as the notch radius decreases. In addition, bilinear damage evolution is proposed to describe the physical behavior of the material when the Lemaitre coupled model is considered. In such a case, special attention must be devoted to the material characterization since coupling between hardening material parameters and damage affects the results. Full article
(This article belongs to the Special Issue Fatigue, Creep Behavior and Fracture Mechanics of Metals)
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15 pages, 7393 KiB  
Article
Effects of Aging Processes on the Dynamic Impact Mechanical Behavior of Mg-Gd System Alloys
by Yibing Ren, Youqiang Wang, Xuezhao Wang and Ying Xu
Metals 2024, 14(10), 1102; https://doi.org/10.3390/met14101102 - 25 Sep 2024
Viewed by 169
Abstract
Exploring the effect of the magnesium alloy aging process on dynamic impact performance could plays an important role in the application of magnesium alloy in automotive lightweighting. In this work, the effects of single-stage, two-stage, and reverse two-stage aging processes on the dynamic [...] Read more.
Exploring the effect of the magnesium alloy aging process on dynamic impact performance could plays an important role in the application of magnesium alloy in automotive lightweighting. In this work, the effects of single-stage, two-stage, and reverse two-stage aging processes on the dynamic mechanical properties of Mg-8.5 Gd-3 Y-0.5 Zr alloy were studied by means of SEM analysis, hardness testing, a quasi-static compression experiment, and SHPB. The results show that the compressive strength of the materials after single-stage, two-stage, and reverse two-stage aging treatments is improved to different degrees compared with that of the alloys in the extruded state. Due to the generation of dynamic precipitation with semi-annular distribution during SHPB, the compressive strength of the reverse two-stage aging alloys reached an excellent 761 MPa, while the two-stage aging alloys had more dynamic precipitation phases at the strain rate of 3500 s−1, resulting in a compressive strength of 730 MPa, which is superior to that of the aluminum alloys used in a wide range of automotive applications. The results of this study can provide a reference for the application of Mg-Gd magnesium alloys under dynamic loading. Full article
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20 pages, 4839 KiB  
Article
Critical Resolved Shear Stress and Work Hardening Determination in HCP Metals: Application to Zr Single Crystals
by Jean-Sébastien Lecomte, Jérôme Crépin and Pierre Barberis
Metals 2024, 14(10), 1101; https://doi.org/10.3390/met14101101 - 25 Sep 2024
Viewed by 194
Abstract
Obtaining precise parameters of deformation modes remains a significant challenge in materials science research. Critical resolved shear stresses (CRSS) and work hardening, particularly in hexagonal metals, are crucial parameters for constitutive laws in crystal plasticity. This paper presents a novel approach to determine [...] Read more.
Obtaining precise parameters of deformation modes remains a significant challenge in materials science research. Critical resolved shear stresses (CRSS) and work hardening, particularly in hexagonal metals, are crucial parameters for constitutive laws in crystal plasticity. This paper presents a novel approach to determine CRSS and specific hardening matrix coefficients for commercially pure zirconium (α-Zr) at room temperature. In situ methods are employed to measure displacement fields using grids applied to the sample surface, while a comprehensive characterization of the activated deformation systems is performed via SEM and TEM. The CRSS for prismatic ⟨a⟩, pyramidal ⟨a⟩, and 101¯2 and 112¯1 twinning systems, as well as the self-hardening for prismatic slip and several work-hardening coefficients (for prismatic/prismatic and prismatic/pyramidal interactions), are reported in Zr single crystals. Finally, the results are compared with findings from the literature and atomistic simulations. Full article
(This article belongs to the Special Issue Metal Plastic Deformation and Forming)
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15 pages, 4344 KiB  
Article
Phase-Field Simulation and Dendrite Evolution Analysis of Solidification Process for Cu-W Alloy Contact Materials under Arc Ablation
by Hanwen Ren, Jian Mu, Siyang Zhao, Junke Li, Yateng Yang, Zhiyun Han, Zexi Xing and Qingmin Li
Metals 2024, 14(10), 1100; https://doi.org/10.3390/met14101100 - 25 Sep 2024
Viewed by 206
Abstract
Cu-W alloys are widely used in high-voltage circuit breaker contacts due to their high resistance to arc ablation, but few studies have analyzed the microstructure of Cu-W alloys under arc ablation. This study applied a phase-field model based on the phase-field model developed [...] Read more.
Cu-W alloys are widely used in high-voltage circuit breaker contacts due to their high resistance to arc ablation, but few studies have analyzed the microstructure of Cu-W alloys under arc ablation. This study applied a phase-field model based on the phase-field model developed by Karma and co-workers to the evolution of dendrite growth in the solidification process of Cu-W alloy under arc ablation. The process of columnar dendrite evolution during solidification was simulated, and the effect of the supercooling degree and anisotropic strength on the morphology of the dendrites during solidification was analyzed. The results show that the solid–liquid interface becomes unstable with the release of latent heat, and competitive growth between dendrites occurs with a large amount of solute discharge. In addition, when the supercooling degree is 289 K, the interface is located at a lower height of only 15 μm, and the growth rate is slow. At high anisotropy, the side branches of the dendrites are more fully developed and tertiary dendritic arms appear, leading to a decrease in the alloy’s relative density and poorer ablation resistance. In contrast, the main dendrites are more developed under high supercooling, which improves the density and ablation resistance of the material. The results in this paper may provide a novel way to study the microstructure evolution and material property changes in Cu-W alloys under the high temperature of the arc for high-voltage circuit breaker contacts. Full article
(This article belongs to the Special Issue Crystallography on Metallic Metasatable Phases in Materials Design, Processing, Science and Engineering)
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19 pages, 7634 KiB  
Article
The Influence of the Hot-Rolling Temperature on the Microstructure and Mechanical Properties of Ti-Nb Microalloyed 21%Cr Ferritic Stainless Steel
by Yahui Meng, Jie Sheng, Zongwen Ma, Yang Gao, Lixu Tuo, Hongyan Duan and Kun Man
Metals 2024, 14(10), 1099; https://doi.org/10.3390/met14101099 - 25 Sep 2024
Viewed by 276
Abstract
Microalloying and heat treatment are essential processing techniques for ferritic stainless steel (FSS). Three different compositions of 21%Cr FSS with 0.28Ti, 0.21Ti + 0.05Nb, and 1.05Ti + 0.17Nb were prepared. The interaction effects of the Nb and Ti contents and hot-rolling annealing on [...] Read more.
Microalloying and heat treatment are essential processing techniques for ferritic stainless steel (FSS). Three different compositions of 21%Cr FSS with 0.28Ti, 0.21Ti + 0.05Nb, and 1.05Ti + 0.17Nb were prepared. The interaction effects of the Nb and Ti contents and hot-rolling annealing on the microstructure, mechanical properties, and precipitate phases of FSS were studied. The microstructure, crystal structure, and precipitation phase of steel at 930, 980, and 1030 °C with Ti-Nb microalloying were investigated using an optical microscope (OM), X-ray diffractometer (XRD), and scanning electron microscope (SEM). The room-temperature tensile properties, surface roughness, and hardness were tested separately. This study found that the composite addition of Ti and Nb had a dual effect of fine-grain strengthening and precipitation strengthening. The 1.05Ti + 0.17Nb steel specimen had a moderate grain size and the best uniformity after hot rolling at 980 °C. The tensile strength and elongation were 454 MPa and 34.2%, which achieved an optimal balance between strength and plasticity. Full article
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23 pages, 4416 KiB  
Article
Water Separation and Formation of Cells with Differential Aeration as Factors Controlling Corrosion of Steel Pipelines in a Crude Oil Storage Facility
by Václav Šefl, Rojina Shrestha and Tomáš Prošek
Metals 2024, 14(10), 1098; https://doi.org/10.3390/met14101098 - 24 Sep 2024
Viewed by 307
Abstract
The mechanism causing the dramatic intensification of the corrosion deterioration of carbon steel pipes in a crude oil storage facility has been investigated. This study considers a number of factors affecting corrosion in crude oil, such as the water content, the corrosivity of [...] Read more.
The mechanism causing the dramatic intensification of the corrosion deterioration of carbon steel pipes in a crude oil storage facility has been investigated. This study considers a number of factors affecting corrosion in crude oil, such as the water content, the corrosivity of the aqueous phase, the kinetics of water–oil separation, the effect of dissolved oxygen, the effect of the crude oil quality, the degree of stagnancy inside of the pipes, the possible contribution of microbially induced corrosion (MIC) and the presence of deposits. The key root of the corrosion intensification was the separation of the water phase, supported by stagnancy, which eventually led to the formation of stable shallow pits surrounded by cathodic areas. Full article
(This article belongs to the Special Issue Corrosion of Metals: Behaviors and Mechanisms)
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16 pages, 10238 KiB  
Article
Optimizing Wear Resistance and Tensile Strength of Nickel-Based Coatings through Tungsten Carbide Reinforcement
by Li Zhang, Shengli Li, Chunlin Zhang, Shihan Zhang, Xingang Ai and Zhiwen Xie
Metals 2024, 14(10), 1097; https://doi.org/10.3390/met14101097 - 24 Sep 2024
Viewed by 252
Abstract
While the addition of WC increases the hardness and wear resistance of coatings, an excessive WC content can also induce crack initiation and propagation, increasing brittleness and leading to premature failure. Therefore, in this study, WC particles were incorporated into nickel-based coatings by [...] Read more.
While the addition of WC increases the hardness and wear resistance of coatings, an excessive WC content can also induce crack initiation and propagation, increasing brittleness and leading to premature failure. Therefore, in this study, WC particles were incorporated into nickel-based coatings by plasma-arc surfacing to optimize their content and distribution, balancing their tensile properties and wear resistance. The coatings were comprehensively evaluated through microstructural analysis, hardness testing, wear resistance assessment, and tensile testing. The results show that as the mass fraction of WC increased from 45% to 65%, the increase in carbon significantly promoted the formation of M7C3, M6C, and M23C6 carbides and suppressed the formation of the γ-phase. The microstructural analysis showed that the content of massive carbides increased significantly with the increasing WC content, and the XPS analysis further confirmed that the changes in the WC and Cr7C3 phases were particularly pronounced in the high-WC coating. The 65% WC coating showed higher hardness (a 232 increase in HV1.0), a lower and more stable coefficient of friction (0.42), and better wear resistance than the 45% WC coating, with a wear rate of 3.329 × 10−6 mm3/(N·m)−1, which was 3.709 × 10−6 mm3/(N·m)−1 lower than that of the 45% WC coating. The conventional tensile test results show that the maximum stress and strain of the 45% WC coating were 71% and 36% higher than those of the 65% WC coating, respectively. In addition, the 45% WC coating exhibited better ductility and quasi-cleavage characteristics, whereas the 65% WC coating showed typical brittle cracking behavior. The results of the field tensile tests also showed that the fracture time of the 65% WC coating was 27 s shorter than that of the 45% WC coating. Overall, the 45% WC coating had a good combination of strength and toughness. Full article
(This article belongs to the Special Issue Friction and Wear of Metallic Materials—State of the Art)
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23 pages, 15459 KiB  
Article
Modeling Microstructure Development upon Continuous Cooling of 42CrMo4 Steel Grade for Large-Size Components
by Sergio Fernandez-Sanchez, Amaia Iza-Mendia and Denis Jorge-Badiola
Metals 2024, 14(10), 1096; https://doi.org/10.3390/met14101096 - 24 Sep 2024
Viewed by 274
Abstract
42CrMo4-type steel grades are widely used in a great variety of components that require ad hoc mechanical properties. However, due to the dimensions of large components and the previous thermomechanical treatments, the presence of heterogeneities in the chemical compositions are expected to impact [...] Read more.
42CrMo4-type steel grades are widely used in a great variety of components that require ad hoc mechanical properties. However, due to the dimensions of large components and the previous thermomechanical treatments, the presence of heterogeneities in the chemical compositions are expected to impact those mechanical properties. In the present work, a detailed analysis of phase transformation behavior upon cooling was carried out through a dilatometry test on samples of 42CrMo4 belonging to a component that has a non-homogeneous chemical distribution. The analysis of the dilatation signals and the quantitative metallography shows a rather complex behavior depending on the cooling rate as well as on the region of observation. Two different phase transformation models based on Li’s approach were applied to the present composition to determine the CCT curve as well as the fraction of the microconstituents. An extensive discussion was carried out on some aspects about Kirkaldy-based approaches that need to be improved so as to attain more reliable quantitative results when modeling phase transformations in heterogenous systems. Full article
(This article belongs to the Special Issue Advances in Phase Transformation Behavior of Steels)
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26 pages, 6292 KiB  
Review
Salar de Atacama Lithium and Potassium Productive Process
by David Torres, Kevin Pérez, Felipe M. Galleguillos Madrid, Williams H. Leiva, Edelmira Gálvez, Eleazar Salinas-Rodríguez, Sandra Gallegos, Ingrid Jamett, Jonathan Castillo, Manuel Saldana and Norman Toro
Metals 2024, 14(10), 1095; https://doi.org/10.3390/met14101095 - 24 Sep 2024
Viewed by 265
Abstract
The average lithium content in the Earth’s crust is estimated at about 0.007%. Despite this, lithium is considered abundant and widely distributed, with significant extraction from various sources. Notably, the brines in the Salar de Atacama are highlighted for their high lithium concentration [...] Read more.
The average lithium content in the Earth’s crust is estimated at about 0.007%. Despite this, lithium is considered abundant and widely distributed, with significant extraction from various sources. Notably, the brines in the Salar de Atacama are highlighted for their high lithium concentration ~1800 mg/L. Lithium is currently recovered from these brines through a solar evaporation process. The brine is transferred through a series of ponds, increasing the lithium concentration from 0.2% to 6% over 18 months, while decanting other minerals like potassium, magnesium, and boron. This method is the most efficient and cost-effective globally due to the Salar de Atacama’s high lithium concentration of approximately 1800 ppm and the region’s intense solar radiation, which facilitates evaporation at no economic cost. This manuscript describes in detail the lithium and potassium extraction processes used in the Salar de Atacama. Full article
(This article belongs to the Special Issue Sustainability Approaches in the Recycling of Light Alloys)
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17 pages, 8186 KiB  
Article
Crack Growth Patterns of Aluminum Tubular Specimens Subjected to Cyclic Tensile Loads
by Lenin Abatta-Jacome, Luis Caminos, Antonio Gonzalez-Herrera and Jose Manuel Garcia-Manrique
Metals 2024, 14(10), 1094; https://doi.org/10.3390/met14101094 - 24 Sep 2024
Viewed by 229
Abstract
This study presents a detailed analysis of a fatigue test campaign in order to identify different crack patterns. It was conducted on 6061-T6 aluminum tubular specimens featuring an internal diameter of 10 mm and different thicknesses (2, 3 and 4 mm). These specimens [...] Read more.
This study presents a detailed analysis of a fatigue test campaign in order to identify different crack patterns. It was conducted on 6061-T6 aluminum tubular specimens featuring an internal diameter of 10 mm and different thicknesses (2, 3 and 4 mm). These specimens were subjected to cyclic tensile loads with a load ratio of R = 0.1, utilizing a sinusoidal load function at a frequency of 3 Hz. The investigation examines the crack growth rates, the stress intensity factor, and the final and intermediate fracture zones by applying overloads in some cases. The differences with two-dimensional specimens and the importance of this study for the interpretation of results with biaxial loading states are highlighted. The different states of crack growth detected are analyzed using artificial vision techniques. The differences between the exterior and interior faces of the specimen are revealed, and a series of states prior to the formation of the radial crack front expected in these specimens are identified. Full article
(This article belongs to the Special Issue Fatigue, Damage and Fracture of Metallic Materials)
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15 pages, 8735 KiB  
Article
Enhanced Strengthening and Toughening of T6-Treated 7046 Aluminum Alloy through Severe Plastic Deformation
by Yuna Wu, Hongchen Dong, Hao Huang, Ting Yuan, Jing Bai, Jinghua Jiang, Feng Fang and Aibin Ma
Metals 2024, 14(10), 1093; https://doi.org/10.3390/met14101093 - 24 Sep 2024
Viewed by 268
Abstract
The 7046 aluminum alloy possesses a favorable fatigue property, corrosion resistance and weldability, but its moderate strength and plasticity limit its wider application and development. In the present study, severe plastic deformation (SPD) was applied prior to T6 treatment to significantly enhance the [...] Read more.
The 7046 aluminum alloy possesses a favorable fatigue property, corrosion resistance and weldability, but its moderate strength and plasticity limit its wider application and development. In the present study, severe plastic deformation (SPD) was applied prior to T6 treatment to significantly enhance the strength and toughness of the 7046 aluminum alloy. The results show that the alloy processed by four passes of equal channel angular pressing (ECAP) at 300 °C prior to T6 treatment exhibits an excellent mechanical performance, achieving an ultimate tensile strength (UTS) and elongation (EL) of 485 MPa and 19%, respectively, which are 18.6% and 375% higher than that of the T6 alloy. The mechanical properties of the alloy are further improved by an additional room temperature (RT) rolling process, resulting in a UTS of 508 MPa and EL of 23.4%, respectively. The increased presence of η′ and Al6Mn phases in the 300°C4P-R80%-T6 and 300°C4P-T6 alloys contributes to a strengthening and toughening enhancement in the SPD-processed T6 alloy. The findings from this work may shed new insights into enhancing the 7046 aluminum alloy. Full article
(This article belongs to the Special Issue Development, Characterization and Properties of High-Performance Aluminum Alloys)
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