Advanced Crystalline Materials, Mechanical Properties and Innovative Production Systems (2nd Edition)

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Crystalline Metals and Alloys".

Deadline for manuscript submissions: closed (21 July 2024) | Viewed by 16348

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Guest Editor
Faculty of Technical and Economic Sciences, Witelon Collegium State University, Sejmowa 5A, 59-220 Legnica, Poland
Interests: foundry; material engineering; metals; composites; mechanical properties; corrosion; wear; heat treatment; management and production engineering
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Guest Editor
Department of Mechanics, Material Science and Engineering, Faculty of Mechanical Engineering, Wrocław University of Science and Technology, Smoluchowskiego 25, 50-370 Wrocław, Poland
Interests: fatigue damage; reliability analysis; fatigue crack growth theory; failure analysis of metal materials; micromechanics of materials; multiscale materials modeling
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Guest Editor
Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, ul. Łukasiewicza 5, 50-371 Wrocław, Poland
Interests: machine learning; intelligent manufacturing systems; optimization of production systems; modeling and simulation of manufacturing processes; risk assessment in manufacturing systems
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Crystalline materials are the most commonly used materials. Thanks to their crystalline structure, they are characterized by a number of beneficial properties, including mechanical and functional properties. In recent years, many discoveries and advances have been made in materials engineering, which materials scientists are using to create countless novel materials through the use of modern modeling and simulation systems, technologies, and manufacturing techniques that enable obtaining advanced materials. These materials include high-quality construction materials, composites, and nanomaterials. For many of the emerging material solutions today, the main focus is on the mechanical properties of the materials. As a result, they are used on a large scale in land and water construction, automotive, aviation, and space engineering, as well as in the power industry.

Mechanical properties are an extremely important metric for evaluating materials, as they determine which areas the materials can be used in. Hardness and strength are the main mechanical properties. The values of these quantities are usually correlated. In order to obtain high hardness/strength, treatments are used to strengthen the structure, and they consist of the appropriate selection of chemical composition and technological processes. These activities must guarantee that a structure is obtained that ensures high hardness and strength. The obtained materials are usually hard and statically strong, but most often also brittle. Because they are not plastic, they have poor impact strength and are not resistant to abrasive wear, considering dynamic factors. Therefore, achieving a high synergy between strength and ductility is a major challenge and has become a topic of general interest.

From the perspective of the exploitation of structural elements, machines, and devices, factors reducing their ability to transfer external loads are also important. These factors include corrosion and wear.

Simulation and modeling processes play a key role in facilitating the rapid dissemination of advanced materials and reaping the benefits they offer. This is of great importance for production processes in terms of costs and product quality. The modeling and simulation of production processes are the best and most cost-effective methods of testing and evaluating the properties of advanced materials in terms of their usability and the quality of the resulting product. Modeling and simulations also enable an easier and cheaper assessment of the effectiveness of production processes and systems, also from the point of view of their management.

In the proposed Special Issue, we are seeking original research articles, perspectives, and reviews on technology, microstructure, mechanical properties, and various applications of crystalline materials. We invite you to submit works that include modeling and simulation of production processes and systems and their management in production, as well as forecasts of the future development of materials and production systems. Potential topics include, but are not limited to, the following: 

  • Alloy design and manufacturing of crystalline materials;
  • Crystalline nanomaterials and composites;
  • Mechanical properties and fracture mechanics;
  • Crystalline materials for power engineering;
  • Casting, welding, and additive manufacturing;
  • Advanced heat treatment techniques;
  • Materials design and modeling, applications in production processes, and their management.

Dr. Daniel Medyński
Dr. Anna Burduk
Dr. Grzegorz Lesiuk
Guest Editors

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

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Keywords

  • metals and alloys
  • nanomaterials
  • composites
  • solidification and crystallization
  • phase transformations
  • materials modelling
  • casting and welding
  • additive manufacturing
  • heat treatment
  • corrosion
  • mechanical properties
  • fracture mechanics
  • production management
  • production processes and systems

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Related Special Issue

Published Papers (13 papers)

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Research

18 pages, 14498 KiB  
Article
Evolution of the Microstructure, Phase Composition and Thermomechanical Properties of the CuZnIn Alloys, Achieved by Thermally Controlled Phase Transitions
by Anna Sypien, Tomasz Czeppe, Anna Wojcik, Grzegorz Garzel, Anna Goral, Marek Kopyto and Zbigniew Swiatek
Crystals 2024, 14(7), 669; https://doi.org/10.3390/cryst14070669 - 22 Jul 2024
Viewed by 651
Abstract
Ternary alloys with CuZnIn compositions based on the binary CuZn diagram and the modeled ternary system solidus projection were investigated. The as-cast alloys, hot-rolled sheets, and samples annealed at low temperature were examined. It was found that the α-CuZn solution phase, with minor [...] Read more.
Ternary alloys with CuZnIn compositions based on the binary CuZn diagram and the modeled ternary system solidus projection were investigated. The as-cast alloys, hot-rolled sheets, and samples annealed at low temperature were examined. It was found that the α-CuZn solution phase, with minor indium additions (1–2% at.), was the primary phase crystallizing during casting and remained stable at low temperatures. The ternary phase with an approximate composition of Cu8(In,Zn)4.5 and a structure analogous to the high-temperature γ-Cu9In4 phase crystallized from the liquid state and remained stable at low temperatures. This behavior results from the stabilization against peritectoidal decomposition by the Zn atoms when substituting In in the structure. A new phase γ*-Cu9(In,Zn)4 with a modified structure was identified, characterized by a reduced unit cell and an altered electronic structure. The hot-rolling process preserves the phase composition and forms a composite-like structure, with the matrix composition of γ* and large ellipsoidal α-CuZn solution particles. On a microscale, the γ* matrix exhibited a specific structure resulting from segregation processes and was composed of micrometer-sized α-CuZn(In) solution particles and nano-sized β-CuZn phase precipitates. Low-temperature annealing intensifies the γ* matrix decomposition through binary phase precipitation. Full article
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15 pages, 9769 KiB  
Article
Ag-Coated Super Duplex Stainless Steel AISI2507 with or without Crystallization of Secondary Phase as Advanced Li-Ion Battery Case Material
by Hyeongho Jo, Jung-Woo Ok, Yoon-Seok Lee, Yonghun Je, Shinho Kim, Seongjun Kim, Jinyong Park, Jaeyeong Lee, Byung-Hyun Shin, Jang-Hee Yoon and Yangdo Kim
Crystals 2024, 14(7), 653; https://doi.org/10.3390/cryst14070653 - 16 Jul 2024
Viewed by 888
Abstract
Li-ion batteries used in portable electronic devices and electric vehicles require high safety standards, necessitating the use of high-performance structural materials for battery casings. Super duplex stainless steel (SDSS) is a structural material suitable for portable electronic products owing to its excellent strength [...] Read more.
Li-ion batteries used in portable electronic devices and electric vehicles require high safety standards, necessitating the use of high-performance structural materials for battery casings. Super duplex stainless steel (SDSS) is a structural material suitable for portable electronic products owing to its excellent strength and corrosion resistance. SDSS AISI2507 was used to construct a Li-ion battery casing, a Ag coating was applied via physical vapor deposition (PVD) after the heat treatment of AISI2507 with or without a secondary phase, and the coating thickness was controlled by varying the PVD time. The thickness of the Ag coating layer increased proportionally with time, thereby enhancing the electrical conductivity. The structure and coating behavior were confirmed using FE-SEM, XRD, and GDS. The secondary phase was crystallized by the segregation of the alloy and formed a BCC structure. The FCC lattice structure exhibited excellent coating behavior on the austenite (FCC structure) of AISI2507. Conversely, the secondary phase exhibited low adhesion owing to differences in composition and crystal structure. However, the Ag coating layer on AISI2507 exhibited excellent electrical conductivity, outperforming conventional Ni-plated Li-ion battery casings comprising AISI304. However, the precipitation of the secondary phase must be controlled, as the formation of the secondary phase acts as a factor that decreases electrical conductivity from 58.8 to 53.6 (ICAS) %. The excellent performance of Ag-coated AISI2507 makes it suitable for the fabrication of enhanced Li-ion battery casings. Full article
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23 pages, 30432 KiB  
Article
Application of Organo-Modified Silica Nanoparticles to Improve the Load-Bearing Capacity of Bonded Joints of Dissimilar Steel Substrates
by Anna Guzanová, Dagmar Draganovská, Miroslav Tomáš, Petr Szelag, Nikita Veligotskyi, Miroslav Džupon and Marek Vojtko
Crystals 2024, 14(6), 558; https://doi.org/10.3390/cryst14060558 - 17 Jun 2024
Viewed by 1055
Abstract
The paper deals with the joining of dissimilar steels by adhesive bonding. The base materials for the experimental work were deep-drawn low-carbon steel DC04, and hot-dip galvanized HSLA steel HX340LAD+Z. Adhesive bonding was performed using rubber-based and epoxy-based adhesives. The research aimed to [...] Read more.
The paper deals with the joining of dissimilar steels by adhesive bonding. The base materials for the experimental work were deep-drawn low-carbon steel DC04, and hot-dip galvanized HSLA steel HX340LAD+Z. Adhesive bonding was performed using rubber-based and epoxy-based adhesives. The research aimed to verify the importance of surface preparation of steel substrates using a formulation with organically modified silica nanoparticles and epoxy organic functional groups, where one end of the functional group can be incorporated into the organic binder of the coating material and the other end can be firmly bonded to substances of an inorganic nature (metals). Since the binder base of adhesives is very similar to that of coatings, verifying the performance of this surface preparation when interacting with the adhesive is necessary. The load-bearing tensile shear capacity of single-lapped joints and the resistance of the joints against corrosion-induced disbanding in a climate chamber were tested. The energy dissipated by the joints up to fracture was calculated from the load-displacement curves. Bonded joints with organosilane were compared with joints without surface preparation and joints prepared by chroman-free zirconate passivation treatment. Exposure of the joints in the climatic chamber did not cause a relevant reduction in the characteristics of the joints. Organosilicate formulation was proved effective when bonding ungalvanized steels with a rubber-based structural adhesive, where it improves the bond quality between the adhesive and the substrate. Full article
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14 pages, 916 KiB  
Article
Research on Fe Removal, Regeneration Process, and Mechanical Properties of Mg Alloy AM50A
by Zhao Chen, Changfa Zhou, Wenbo Liu, Sanxing Chen, Cong Gao, Shaowei Jia, Xiaowen Yu, Wang Zhou, Bolin Luo and Qingshuang Zhang
Crystals 2024, 14(5), 407; https://doi.org/10.3390/cryst14050407 - 26 Apr 2024
Cited by 1 | Viewed by 753
Abstract
In recent years, the widespread application of Mg alloy casting and Mg alloy products has generated a large amount of Mg alloy waste. This experiment used a single factor experimental analysis method to study the optimal process for removing Fe from Mg alloy [...] Read more.
In recent years, the widespread application of Mg alloy casting and Mg alloy products has generated a large amount of Mg alloy waste. This experiment used a single factor experimental analysis method to study the optimal process for removing Fe from Mg alloy AM50A waste, and developed an efficient Fe removal and regeneration process for Mg alloy AM50A. It was found that the optimal refining temperature for removing Fe ions was 670 °C, the optimal refining (RJ-2) agent mass ratio was 1.5%, and the optimal refining time was 40 min. Regenerated J40-1.5-AM50A Mg alloy was prepared using the best refining process, and its composition and mechanical properties were tested and analyzed. The experimental results show that the composition of the regenerated J40-1.5-AM50A Mg alloy prepared by this method is consistent with AM50A, with an Fe removal rate of 96.2%. The mechanical properties were improved compared to the original AM50A sample, with a maximum tensile strength increase of 1.611 KN and a tensile strength increase of 26.333 MPa. The elongation after fracture is 2.25 times that of the original sample. Research has shown that the RJ-2 refining agent can provide mechanical properties of magnesium alloys during the refining process. By analyzing the composition, XRD, SEM, and EDS of AM50A (Fe) and J40-1.5-AM50A, it was found that the refining process accelerates the removal of Fe in the form of Fe deposition. Full article
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11 pages, 3784 KiB  
Article
Crystallization of Secondary Phase on Super-Duplex Stainless Steel SAF2507: Advanced Li-Ion Battery Case Materials
by Byung-Hyun Shin, Dohyung Kim and Jang-Hee Yoon
Crystals 2024, 14(4), 378; https://doi.org/10.3390/cryst14040378 - 18 Apr 2024
Cited by 1 | Viewed by 1318
Abstract
The demand for Li-ion batteries has increased because of their extensive use in vehicles and portable electronic devices. This increasing demand implies greater interaction between batteries and humans, making safety a paramount concern. Although traditional batteries are fabricated using Al, recent efforts to [...] Read more.
The demand for Li-ion batteries has increased because of their extensive use in vehicles and portable electronic devices. This increasing demand implies greater interaction between batteries and humans, making safety a paramount concern. Although traditional batteries are fabricated using Al, recent efforts to enhance safety have led to the adoption of AISI304. The strength and corrosion resistance of AISI304 are greater than those of Al; however, issues such as stress-induced phase transformation and low high-temperature strength have been observed during processing. Duplex stainless steel SAF2507, which is characterized by a dual-phase structure consisting of austenite and ferrite, exhibits excellent strength and corrosion resistance. Although SAF2507 demonstrated outstanding high-temperature strength up to 700 °C, it precipitated a secondary phase. The precipitation of this secondary phase, believed to be caused by the precipitation of the carbides of Cr and Mo, has been extensively studied. Research on the precipitation of the secondary phase near 1000 °C has been conducted owing to the annealing temperature (1100 °C) of the SAF2507 solution. The secondary phase precipitates at approximately 1000 °C because of slow cooling rates. However, few studies have been conducted on the precipitation of the secondary phase at approximately 700 °C. This study analyzed the precipitation behavior of the secondary phase at 700 °C when SAF2507 was applied and assessed its safety during heat generation in Li-ion batteries. The precipitation behavior was analyzed using field emission scanning electron microscopy for morphology, energy-dispersive X-ray spectroscopy for composition, and X-ray diffraction for phase identification. Full article
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14 pages, 4725 KiB  
Article
Improved Joint Formation and Ductility during Electron-Beam Welding of Ti6Al4V and Al6082-T6 Dissimilar Alloys
by Georgi Kotlarski, Darina Kaisheva, Maria Ormanova, Borislav Stoyanov, Vladimir Dunchev, Angel Anchev and Stefan Valkov
Crystals 2024, 14(4), 373; https://doi.org/10.3390/cryst14040373 - 16 Apr 2024
Cited by 2 | Viewed by 1212
Abstract
The current work is based on investigating the influence of different technological conditions of electron-beam welding on the microstructure and mechanical properties of joints between Ti6Al4V and Al6082-T6 dissimilar alloys. The plates were in all cases preheated to 300 °C. Different strategies of [...] Read more.
The current work is based on investigating the influence of different technological conditions of electron-beam welding on the microstructure and mechanical properties of joints between Ti6Al4V and Al6082-T6 dissimilar alloys. The plates were in all cases preheated to 300 °C. Different strategies of welding were investigated such as varying the electron-beam current/welding speed ratio (Ib/vw) and applying a beam offset towards the aluminum side. The heat input during the experiments was varied in order to guarantee full penetration of the electron beam. The macrostructure of the samples was studied, and the results indicated that using a high beam power and a high welding speed leads to an increased formation of defects within the structure of the weld seam. Utilizing a lower beam current along with a lower welding speed leads to the stabilization of the electron-beam welding process and thus to the formation of an even weld seam with next to no defects and high ductility. Using this approach gave the highest ultimate tensile strength (UTS) of 165 MPa along with a yield strength (YS) of 80 MPa and an elongation (ε) figure of 18.4%. During the investigation, improved technological conditions of electron-beam welding of Ti6Al4V and Al6082-T6 dissimilar alloys were obtained, and the results were discussed regarding possible practical applications of the suggested approach along with its scientific contribution to developing further strategies for electron-beam welding of other dissimilar alloys. The downsides and the economic effect of the presented method for welding Ti6Al4V and Al6082-T6 were also discussed. Full article
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11 pages, 733 KiB  
Article
Machine Learning-Based Predictions of Power Factor for Half-Heusler Phases
by Kaja Bilińska and Maciej J. Winiarski
Crystals 2024, 14(4), 354; https://doi.org/10.3390/cryst14040354 - 9 Apr 2024
Viewed by 1231
Abstract
A support vector regression model for predictions of the thermoelectric power factor of half-Heusler phases was implemented based on elemental features of ions. The training subset was composed of 53 hH phases with 18 valence electrons. The target values were calculated within the [...] Read more.
A support vector regression model for predictions of the thermoelectric power factor of half-Heusler phases was implemented based on elemental features of ions. The training subset was composed of 53 hH phases with 18 valence electrons. The target values were calculated within the density functional theory and Boltzmann equation. The best predictors out of over 2000 combinations regarded for the p-type power factor at room temperature are: electronegativity, the first ionization energy, and the valence electron count of constituent ions. The final results of support vector regression for 70 hH phases are compared with data available in the literature, revealing good ability to determine favorable thermoelectric materials, i.e., VRhGe, TaRhGe, VRuSb, NbRuAs, NbRuBi, LuNiAs, LuNiBi, TaFeBi, YNiAs, YNiBi, TaRuSb and NbFeSb. The results and discussion presented in this work should encourage further fusion of ab initio investigations and machine learning support, in which the elemental features of ions may be a sufficient input for reasonable predictions of intermetallics with promising thermoelectric performance. Full article
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17 pages, 7742 KiB  
Article
Cavitation Erosion of the Austenitic Manganese Layers Deposited by Pulsed Current Electric Arc Welding on Duplex Stainless Steel Substrates
by Ion Mitelea, Daniel Mutașcu, Ion-Dragoș Uțu, Corneliu Marius Crăciunescu and Ilare Bordeașu
Crystals 2024, 14(4), 315; https://doi.org/10.3390/cryst14040315 - 28 Mar 2024
Viewed by 2733
Abstract
Fe-Mn-Cr-Ni alloys like Citomangan, delivered in the form of powders, tubular wires, and coated electrodes, are intended for welding deposition operations to create wear-resistant layers. Their main characteristic is their high capacity for surface mechanical work-hardening under high shock loads, along with high [...] Read more.
Fe-Mn-Cr-Ni alloys like Citomangan, delivered in the form of powders, tubular wires, and coated electrodes, are intended for welding deposition operations to create wear-resistant layers. Their main characteristic is their high capacity for surface mechanical work-hardening under high shock loads, along with high toughness and wear resistance. In order to increase the resistance to cavitation erosion, hardfacing of Duplex stainless steel X2CrNiMoN22-5-3 with Citomangan alloy was performed using a new welding technique, namely one that uses a universal TIG source adapted for manual welding with a coated electrode in pulsed current. Cavitation tests were conducted in accordance with the requirements of ASTM G32—2016 standard. Comparing the characteristic cavitation erosion parameters of the manganese austenitic layer, deposited by this new welding technique, with those of the reference steel, highlights an 8–11 times increase in its resistance to cavitation erosion. Metallographic investigations by optical microscopy and scanning electron microscopy (SEM), as well as hardness measurements, were carried out to understand the cavitation phenomena. Full article
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13 pages, 14003 KiB  
Article
Effects of Si Addition on Interfacial Microstructure and Corrosion Resistance of Hot-Dip Zn–Al–Mg–Si Alloy-Coated Steel
by Seong-Min So, Srinivasulu Grandhi, Eui-Pyo Kwon and Min-Suk Oh
Crystals 2024, 14(4), 294; https://doi.org/10.3390/cryst14040294 - 22 Mar 2024
Viewed by 1055
Abstract
Alloy coatings protect steel from corrosion in various applications. We investigated the effects of Si addition on the microstructure, electrochemical behavior, and corrosion resistance of steel sheets coated with a hot-dip Zn–Mg–Al–Si alloy using a batch-type galvanization process. Microstructural analysis revealed that the [...] Read more.
Alloy coatings protect steel from corrosion in various applications. We investigated the effects of Si addition on the microstructure, electrochemical behavior, and corrosion resistance of steel sheets coated with a hot-dip Zn–Mg–Al–Si alloy using a batch-type galvanization process. Microstructural analysis revealed that the Zn–Al–Mg alloy coating layer contained a significant amount of Fe that diffused from the substrate, leading to delamination due to the formation of brittle Fe–Zn intermetallic compounds. However, the introduction of Si resulted in the formation of a stable Fe2Al3Si inhibition layer at the substrate–coating interface; this layer prevented interdiffusion of Fe as well as enhanced the coating adhesion. Additionally, the formation of acicular Mg2Si phases on the coating surface improved the surface roughness. As the Si content increased, the corrosion resistance of the coating improved. Specifically, the Zn–Al–Mg coating layer with 0.5 wt.% Si exhibited excellent anti-corrosion performance, without red rust formation on its surface even after 2600 h, during a salt spray test. Full article
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14 pages, 2234 KiB  
Article
CaH2-Assisted Molten Salt Synthesis of Zinc-Rich Intermetallic Compounds of RhZn13 and Pt3Zn10 for Catalytic Selective Hydrogenation Application
by Yasukazu Kobayashi, Koharu Yamamoto and Ryo Shoji
Crystals 2024, 14(3), 278; https://doi.org/10.3390/cryst14030278 - 15 Mar 2024
Viewed by 1215
Abstract
Zinc-included intermetallic compound catalysts of RhZn, PtZn, and PdZn with a molar ration of Zn/metal = 1/1, which are generally prepared using a hydrogen reduction approach, are known to show excellent catalytic performance in some selective hydrogenations of organic compounds. In this study, [...] Read more.
Zinc-included intermetallic compound catalysts of RhZn, PtZn, and PdZn with a molar ration of Zn/metal = 1/1, which are generally prepared using a hydrogen reduction approach, are known to show excellent catalytic performance in some selective hydrogenations of organic compounds. In this study, in order to reduce the incorporated mounts of the expensive noble metals, we attempted to prepare zinc-rich intermetallic compounds via a CaH2-assisted molten salt synthesis method with a stronger reduction capacity than the common hydrogen reduction method. X-ray diffraction results indicated the formation of RhZn13 and Pt3Zn10 in the samples prepared by the reduction of ZnO-supported metal precursors. In a hydrogenation reaction of p-nitrophenol to p-aminophenol, the ZnO-supported RhZn13 and Pt3Zn10 catalysts showed a higher selectivity than the RhZn/ZnO and PtZn/ZnO catalysts with the almost similar conversions. Thus, it was demonstrated that the zinc-rich intermetallic compounds of RhZn13 and Pt3Zn10 could be superior selective hydrogenation catalysts compared to the conventional intermetallic compound catalysts of RhZn and PtZn. Full article
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13 pages, 16522 KiB  
Article
Effect of Oxygen in Mo-TM (TM = Ti, Zr, Hf) Solid Solutions as Studied with Density Functional Theory Calculations
by Rachid Stefan Touzani, Rostyslav Nizinkovskyi and Manja Krüger
Crystals 2024, 14(3), 213; https://doi.org/10.3390/cryst14030213 - 23 Feb 2024
Cited by 1 | Viewed by 1072
Abstract
Mo-Ti-Si, Mo-Zr-B, and Mo-Hf-B are promising alloy systems for high-temperature applications as they show higher toughness and higher creep resistance than other Mo-based alloys. Regarding ductility and toughness, the chemical composition of the Mo solid-solution phase is the main parameter with which to [...] Read more.
Mo-Ti-Si, Mo-Zr-B, and Mo-Hf-B are promising alloy systems for high-temperature applications as they show higher toughness and higher creep resistance than other Mo-based alloys. Regarding ductility and toughness, the chemical composition of the Mo solid-solution phase is the main parameter with which to tweak these properties of multiphase Mo-based alloys. Besides the common solid-solution hardening, one goal is to minimize embrittlement by decreasing the detrimental effects of interstitials like oxygen atoms in Mo alloys, which might be present in the bulk material due to trapping. For a better understanding of the trapping mechanisms and behavior of Mo solid solutions, the bonding situation and interaction of Mo atoms with the atoms of the alloying partners, as well as oxygen atoms, is worthwhile to investigate. For this, an in-depth analysis of the chemical bonding situation with calculations based on density functional theory in selected Mo-TM(-O) (TM = Ti, Zr, Hf) solid solutions is conducted in this work. It is shown that Ti atoms in a Mo solid solution are strong traps for oxygen atoms, while Hf and, even more clearly, Zr atoms are not. It is pointed out that the ionic and covalent interactions are the primary influence on the trapping behavior, as the change in ionic and covalent interactions between trapping and nontrapping models follows the trend Mo-1Ti > Mo-1Hf > Mo-1Zr, which resembles the trend of the trapping energy. Full article
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12 pages, 7029 KiB  
Article
Cast Microstructure and Crystallographic Features of Al3Sc Dendrites in High Sc-Contained Al-Sc Alloys
by Jinjiang He, Qian Jia, Zhaochong Ding, Xingquan Wang, Xiaomeng Cao, Ziqi Cao and Xinfu Gu
Crystals 2024, 14(2), 200; https://doi.org/10.3390/cryst14020200 - 19 Feb 2024
Viewed by 1271
Abstract
Al-Sc alloys containing high Sc content are employed as sputtering targets for the fabrication of high-performance piezoelectric films during magnetic sputtering. Due to the high proportion of the Al3Sc phase, their workability is quite limited, and they are often used in [...] Read more.
Al-Sc alloys containing high Sc content are employed as sputtering targets for the fabrication of high-performance piezoelectric films during magnetic sputtering. Due to the high proportion of the Al3Sc phase, their workability is quite limited, and they are often used in the as-cast state. In this study, the crystallography of Al3Sc dendrites in as-casted Al-10at.%Sc and Al-20at.%Sc samples is examined using electron backscatter diffraction (EBSD). With increasing Sc content, the fraction of Al3Sc also increases. The Al3Sc dendrites exhibit a cubic relationship with the Al matrix in both alloys. However, in Al-10%Sc alloys, the facets of the Al3Sc dendrites are parallel to {001} planes, while twinning is observed in Al-20at.%. The twinning plane is parallel to the {111} plane, and the dendrite growth direction aligns with the <110> directions. The different morphologies of the dendrite structures in these two alloys are discussed in relation to thermodynamic and kinetic considerations based on the phase diagram and nucleation rate. Full article
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13 pages, 19810 KiB  
Article
High-Temperature Phase Transformations in Al-Li-Cu-Mg-Zr-Sc Alloy Studied via In Situ Electron Microscopy
by Rostislav Králík, Lucia Bajtošová, Barbora Kihoulou, Dalibor Preisler and Miroslav Cieslar
Crystals 2024, 14(2), 136; https://doi.org/10.3390/cryst14020136 - 29 Jan 2024
Cited by 1 | Viewed by 1261
Abstract
A homogenization of billets from Al-Cu-Li-Mg-Sc-Zr alloys should be accomplished at high annealing temperatures exceeding 500 °C. This type of aluminum alloy is susceptible to the depletion of surface layers from Li. Therefore, choosing a suitable homogenization temperature and duration is a crucial [...] Read more.
A homogenization of billets from Al-Cu-Li-Mg-Sc-Zr alloys should be accomplished at high annealing temperatures exceeding 500 °C. This type of aluminum alloy is susceptible to the depletion of surface layers from Li. Therefore, choosing a suitable homogenization temperature and duration is a crucial step in assuring a homogeneous distribution of alloying elements and optimal exploitation of the potential of the alloy. In situ heating in an electron microscope was performed on a twin-roll-cast Al-Cu-Li-Mg-Sc-Zr alloy to understand the peculiarities of the homogenization process. Four types of primary phase particles rich in Cu, Li, Mg, and Fe were identified in the as-cast material. They appear as coarse particles at the boundaries of eutectic cells. Their partial dissolution occurs at temperatures above 450 °C. They are almost fully dissolved at 550 °C, except for complex phases containing Fe and Cu. Small dimensions of eutectic cells in the range of 10 µm assure a homogeneous distribution of the main alloying elements within the matrix after 20 min of annealing at 530 °C. Direct comparison with the same material prepared by mold casting indicates that such short annealing times result in the dissolution of the main primary phase particles but do not assure a homogeneous distribution of the alloying elements in the whole volume of the specimen. Full article
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