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Influence of Pulsed Interference Laser Heating on Crystallisation of Amorphous Fe 77Cu 1Si 13B 9 Ribbons. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2060. [PMID: 38730864 PMCID: PMC11084967 DOI: 10.3390/ma17092060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 04/18/2024] [Accepted: 04/25/2024] [Indexed: 05/13/2024]
Abstract
Amorphous Fe77Cu1Si13B9 ribbons were treated with pulsed laser interference heating (PLIH). The research results will significantly contribute to a better understanding of the impact of PLIH on crystallisation and magnetic properties in precisely defined micro-areas of Fe77Cu1Si13B9 (FeCuSiB) ribbons, which has not yet been described in the literature. It was confirmed here that the use of the laser heating process allowed for the achievement of two-dimensional crystallised micro-areas, periodically distributed (at a distance of 17 µm) on the surface of the amorphous ribbons. The correlation between structural changes (SEM, TEM, HRTEM) and the distribution of magnetic field lines of heated amorphous Fe77Cu1Si13B9 ribbons is presented. Particular attention is paid to structural changes in micro-areas where, by controlling the laser interference heating process, the partial crystallisation of amorphous alloys and the formation of clusters or single nanocrystallites (α-Fe(Si)) embedded in an amorphous matrix occur. The addition of copper to the FeSiB alloy promoted the inhibition of grain growth. Electron holography of micro-areas confirmed shifts in the magnetic field lines in the areas of nanocrystallites, the presence of which in the structure caused the magnetisation of the surrounding amorphous matrix.
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Performance Study of High-Speed Permanent Magnet Synchronous Motor with Amorphous Alloy Considering Temperature Effect. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1928. [PMID: 38673285 PMCID: PMC11051842 DOI: 10.3390/ma17081928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024]
Abstract
Because the magnetic properties of an amorphous alloy (AA) obviously change with the change of temperature, a finite element simulation method for a motor, considering the effect of temperature, is proposed in this paper. In the early design stage of the high-speed permanent magnet synchronous motor (PMSM), the simulation of motor performance is mainly based on the magnetic performance test data at room temperature provided by the material's manufacturer. However, the influence of the temperature rise during the actual operation of the motor will lead to large errors between the simulation results and the measured results. Therefore, it is of great practical significance to measure the magnetic properties of the AA at different temperatures and use them for simulation purposes. In this paper, the magnetization characteristics and iron loss characteristics of the AA and silicon steel (ST100) used for comparison are measured at different temperatures, and the iron loss separation of the two materials at different temperatures is completed, and the hysteresis loss coefficient and eddy current loss coefficient at different temperatures are obtained. On this basis, the performance simulation of a motor model is carried out. The more accurate simulation method proposed in this paper can provide a reference for the design of AA motors in industry.
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Composition Design Strategy for High Entropy Amorphous Alloys. MATERIALS (BASEL, SWITZERLAND) 2024; 17:453. [PMID: 38255621 PMCID: PMC10821324 DOI: 10.3390/ma17020453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/04/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024]
Abstract
High entropy amorphous alloys (HEAAs) are materials that have received much attention in recent years. They exhibit many unique properties; however, research on their composition design method has not been deep enough. In this paper, we summarized some effective composition design strategies for HEAAs. By adjusting the atomic ratio from quinary bulk metallic glasses, Ti20Zr20Cu20Ni20Be20 HEAA with a high fracture strength of 2315 MPa was designed. By similar element addition/substitution, a series of Ti-(Zr, Hf, Nb)-Cu-Ni-Be HEAAs was developed. They possess good glass-forming ability with a maximum critical diameter of 30 mm. Combining elements from those ternary/quaternary bulk metallic glasses has also proved to be an effective method for designing new HEAAs. The effect of high entropy on the property of the alloy, possible composition design methods, and potential applications were also discussed. This paper may provide helpful inspiration for future development of HEAAs.
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The Effect of Fe Addition on the Curie Temperature and Magnetic Entropy of the Gd 45Co 50Al 5 Amorphous Alloy. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4571. [PMID: 37444885 DOI: 10.3390/ma16134571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 06/18/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023]
Abstract
The new magnetic refrigeration (MR) technology, which uses the magnetocaloric effect (MCE) of materials for refrigeration, has shown apparent advantages over the compression refrigeration of freon and other gases. Therefore, how to obtain materials with excellent magnetic entropy change near room temperature is of great significance for the realization of MR. In order to achieve high Tc of a Gd-based amorphous alloy, Gd45Co50Al5 amorphous alloy with good room temperature MCE was selected, and a series of Gd45Co50-xFexAl5 (x = 2, 5, 10) amorphous alloys were prepared by adding Fe instead of Co. In this paper, the effect of Fe addition on the Curie temperature, and the magnetic entropy change in the alloys, were studied thoroughly. The results show that the Curie temperature is increased to 281 K by adding 5% Fe elements, which is mainly related to the enhanced 3d-3d interaction of transition elements caused by Fe addition, and the maximum value of magnetic entropy change is 3.24 J/(kg·K) under a field of 5 T. The results are expected to provide guidance for further improving the room temperature MCE of Gd-based amorphous alloys.
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Scaling Law for Impact Resistance of Amorphous Alloys Connecting Atomistic Molecular Dynamics with Macroscale Experiments. ACS APPLIED MATERIALS & INTERFACES 2023; 15:13449-13459. [PMID: 36749935 DOI: 10.1021/acsami.2c19719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Establishing scaling laws for amorphous alloys is of critical importance for describing their mechanical behavior at different size scales. In this paper, taking Ni2Ta amorphous metallic alloy as a prototype materials system, we derive the scaling law of impact resistance for amorphous alloys. We use laser-induced supersonic micro-ballistic impact experiments to measure for the first time the size-dependent impact response of amorphous alloys. We also report the results of molecular dynamics (MD) simulations for the same system but at much smaller scales. Comparing these results, we determined a law for scaling both length and time scales based on dimensional analysis. It connects the time and length scales of the experimental results on the impact resistance of amorphous alloys to that of the MD simulations, providing a method for bridging the gap in comparing the dynamic behavior of amorphous alloys at various scales and a guideline for the fabrication of new amorphous alloy materials with extraordinary impact resistance.
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Research on Deterioration Mechanism and High-Precision Modelling of the Core Loss for Amorphous Alloys after Wire-Cut Electric Discharge Machining. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2275. [PMID: 36984155 PMCID: PMC10052962 DOI: 10.3390/ma16062275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/07/2023] [Accepted: 03/10/2023] [Indexed: 06/18/2023]
Abstract
Amorphous alloys (AAs) have the advantage of low core loss. Thus, they can be used in high-speed motor applications. However, compared with the nominal performances, the performance of the wire-cut electric discharge machine (W-EDM)-processed AA iron core changes significantly, which limits its popularization. This paper focuses on the performance degradation mechanism of the AA ribbon caused by W-EDM and establishes a modified core loss model after machining. First, a 308 × 15 mm ribbon-shaped AA sample machined by W-EDM was prepared. The characterization and analysis of the magnetic properties, phase, magnetic domain, nano-indentation, micro-morphology, and composition were carried out. In this paper, by analysing the variation in the magnetic domain distribution based on domain width and nano-mechanical properties, it is proposed that the performance degradation range of AA ribbons processed by W-EDM is within 1 mm from the edge. By comparing the microscopic morphology and chemical composition changes in the affected and the unaffected area, this paper presents a mechanism for the property deterioration of W-EDM-processed AA ribbons based on electrochemical corrosion. Finally, a modified loss model for W-EDM-processed AAs is established based on the division of the affected area. This model can significantly improve the accuracy of core loss estimation in the medium- and high-frequency bands commonly used in high-speed motors.
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Research on Chemical Mechanical Polishing Technology for Zirconium-Based Amorphous Alloys. MICROMACHINES 2023; 14:584. [PMID: 36984991 PMCID: PMC10059127 DOI: 10.3390/mi14030584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 02/25/2023] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
Crystallization often occurs in the processing of amorphous alloys, causing the materials lose their excellent properties. The study adopts chemical mechanical polishing of amorphous alloys, presenting the effect of the rotational speed of the polishing turntable, size of abrasive, polishing pressure, and oxidant concentration. The Taguchi method is used to find the best processing parameters, and AFM is used to characterize the machined material surface. At the same time, XPS is used to detect the change of oxide film composition with the addition of oxidant. The results indicate the optimum process parameters: rotational speed of the polishing turntable is 75 r/min, polishing pressure is 28.3 kPa, the size of abrasive is 0.5 μm, and the size of abrasive is a significant factor affecting surface roughness Sa. In addition, as the size of abrasive increases, the material removal rate increases while the surface roughness Sa increases. At pH 10, with an abrasive particle size of 0.5 μm, as the H2O2 concentration increases, the MRR first rapidly decreases at 0.21 wt.% H2O2, and then gradually increases, while the Sa decreases. Furthermore, with the addition of oxidant, the main composition of the surface oxide film changes from oxide to hydroxide, and the contents of Zr4+ and Cu0/Cu1+ elements increase. The findings can provide a feasible chemical mechanical polishing process for zirconium-based amorphous alloys to obtain a satisfactory polishing effect.
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Effect of Local Annealing on Magnetic Flux Distribution and Noise in a Micro-Generator with Amorphous Shell. MICROMACHINES 2022; 13:2086. [PMID: 36557384 PMCID: PMC9781415 DOI: 10.3390/mi13122086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
This study examined micro-alternators with two different housing structures--an uncoated shell and a shell coated with an iron-based amorphous-alloy soft magnetic material. The electromagnetic power and noise characteristics of generators with these shell structures were measured and analyzed. The material used for the shell coating was the SA1 amorphous alloy. The magnetic property of the SA1 material was evaluated, including its hysteresis expansion, hysteresis-loop parameters, α-Fe crystal formation, thermogravimetric transfer, and Curie temperature. The center point of the casing was subjected to flame local-heating annealing to attain ferromagnetism and paramagnetism material characteristics. The experimental shell was between these magnetic-phase-transition properties and was used to observe the magnetic power and noise characteristics of the microgenerator. The measured magnetic flux at the center of the amorphous shell was 1.2-2.4 mT, and the magnetic flux distributed around the shell was 0.6-1.0 mT. The generator with the amorphous-alloy shell had the lowest demagnetization rate in the permanent magnet region, which was close to the bottom of the pole piece, and the magnetic flux leakage of the pole-piece side frame changed the magnetic flux path, thus affecting the demagnetization performance. For the noise experiment, the flame-annealing temperature of the local center point of the amorphous casing reached the Curie temperature, and the noise characteristics of the casing can be reduced by 15 dB compared to those of the generator without the casing. However, the overall performance of generator harmonics and power were not fully improved.
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Metallic Glass-Reinforced Metal Matrix Composites: Design, Interfaces and Properties. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8278. [PMID: 36499775 PMCID: PMC9739044 DOI: 10.3390/ma15238278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/11/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
When metals are modified by second-phase particles or fibers, metal matrix composites (MMCs) are formed. In general, for a given metallic matrix, reinforcements differing in their chemical nature and particle size/morphology can be suitable while providing different levels of strengthening. This article focuses on MMCs reinforced with metallic glasses and amorphous alloys, which are considered as alternatives to ceramic reinforcements. Early works on metallic glass (amorphous alloy)-reinforced MMCs were conducted in 1982-2005. In the following years, a large number of composites have been obtained and tested. Metallic glass (amorphous alloy)-reinforced MMCs have been obtained with matrices of Al and its alloys, Mg and its alloys, Ti alloys, W, Cu and its alloys, Ni, and Fe. Research has been extended to new compositions, new design approaches and fabrication methods, the chemical interaction of the metallic glass with the metal matrix, the influence of the reaction products on the properties of the composites, strengthening mechanisms, and the functional properties of the composites. These aspects are covered in the present review. Problems to be tackled in future research on metallic glass (amorphous alloy)-reinforced MMCs are also identified.
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Sm-Co-based amorphous alloy films for zero-field operation of transverse thermoelectric generation. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2022; 23:767-782. [PMID: 36386550 PMCID: PMC9662036 DOI: 10.1080/14686996.2022.2138538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/05/2022] [Accepted: 10/17/2022] [Indexed: 06/15/2023]
Abstract
Transverse thermoelectric generation using magnetic materials is essential to develop active thermal engineering technologies, for which the improvements of not only the thermoelectric output but also applicability and versatility are required. In this study, using combinatorial material science and lock-in thermography technique, we have systematically investigated the transverse thermoelectric performance of Sm-Co-based alloy films. The high-throughput material investigation revealed the best Sm-Co-based alloys with the large anomalous Nernst effect (ANE) as well as the anomalous Ettingshausen effect (AEE). In addition to ANE/AEE, we discovered unique and superior material properties in these alloys: the amorphous structure, low thermal conductivity, and large in-plane coercivity and remanent magnetization. These properties make it advantageous over conventional materials to realize heat flux sensing applications based on ANE, as our Sm-Co-based films can generate thermoelectric output without an external magnetic field. Importantly, the amorphous nature enables the fabrication of these films on various substrates including flexible sheets, making the large-scale and low-cost manufacturing easier. Our demonstration will provide a pathway to develop flexible transverse thermoelectric devices for smart thermal management.
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Direct Observation of Evolution from Amorphous Phase to Strain Glass. MATERIALS (BASEL, SWITZERLAND) 2022; 15:ma15227900. [PMID: 36431386 PMCID: PMC9692269 DOI: 10.3390/ma15227900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/09/2022] [Accepted: 11/07/2022] [Indexed: 06/12/2023]
Abstract
The amorphous phase and strain glass are both disordered states of solids. The amorphous phase is an atomic packing disordered phase, while strain glass is a glassy state with transformation strain disorder in a crystalline matrix, which both bring extraordinary properties to alloys. Previous studies have mostly focused on the properties and structure of single glass; however, the link between them has seldom been considered. In this work, the specimen of the almost amorphous state was obtained from the heavy-defects-doping Fe67.8Pd32.2 strain glass ingot by arc melting and 90% cold rolling, which were characterized by amorphous packages in X-ray diffraction and amorphous rings in transmission electron microscope diffraction. The evolution from the amorphous phase (metallic glass) back to strain glass was directly observed by an in situ high-resolution transmission electron microscope, which revealed that strain nanodomains began to form on the amorphous matrix below the crystallization temperature of the amorphous phase. Here, direct observation of the evolution process provides a theoretical basis for achieving precise control of crystallinity to obtain the desired microstructure, while the study of the unusual crystallization process offers a possible way to tailor the mechanical and functional properties through tuning the amorphous and strain glass coexistence. This work presents the specific pathway and realization possibilities for the design of glass composite materials with enhanced properties.
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Formation and Penetration Properties of a Shaped Charge with Zr 41.2Ti 13.8Cu 12.5Ni 10Be 22.5 Liner. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3947. [PMID: 36432234 PMCID: PMC9698890 DOI: 10.3390/nano12223947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/03/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
In the military field, determining how to increase the hole-expanding ability of shaped charge warheads is a key and difficult issue with respect to warhead development. Amorphous alloys have grains or grain boundaries, with unique mechanical properties. Zr41.2Ti13.8Cu12.5Ni10Be22.5 can be used as the liner material of shaped charges, resulting in high-speed particle flows that differ from those of traditionally shaped charges. In this paper, based on the analysis of the mechanical response characteristics of Zr41.2Ti13.8Cu12.5Ni10Be22.5 and its fracture morphology under impact, combined with the formation theory of shaped charge jets, a semi-empirical formula is derived to calculate the velocity of non-cohesive high-speed particle flow considering the elastic strain energy loss. Additionally, the reliability of the proposed theoretical model is verified through experiments. The penetration process of Zr-based amorphous alloy high-speed particle flow into a concrete target is theoretically analyzed, and the penetration stages of the high-speed particle flow into the target are clearly distinguished. Combined with the penetration theory of shaped charge particle jets, a high-speed particle flow penetration model is proposed, and a pore expansion model is established through an energy method. The experimentally obtained data on depth of penetration are in agreement with the theoretical calculation results.
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Glass-Forming Ability and Corrosion Behavior of Ti-Based Amorphous Alloy Ti-Zr-Si-Fe. MATERIALS (BASEL, SWITZERLAND) 2022; 15:7229. [PMID: 36295294 PMCID: PMC9608703 DOI: 10.3390/ma15207229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/09/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Ti-based alloy Ti75Zr11Si9Fe5 (At %) and Ti66Zr11Si15Fe5Mo3 (At %) ribbons are fabricated by a single roller spun-melt technique, according to the three empirical rules. Both alloys are found to have a large, supercooled liquid region (ΔTx) before crystallization that reaches 80-90 K. The results show that both alloys possess excellent glass-forming abilities. The electrochemical measurement proves both amorphous alloys possess relatively high corrosion resistance in 3 mass% NaCl solution.
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Effect of Pre-Oxidation Treatment on Corrosion Resistance of FeCoSiBPC Amorphous Alloy. MATERIALS 2022; 15:ma15093206. [PMID: 35591540 PMCID: PMC9099908 DOI: 10.3390/ma15093206] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 12/10/2022]
Abstract
In this paper, the corrosion resistance of FeCoSiBPC amorphous alloy after pre-oxidation and non-oxidation heat treatment is investigated. The corrosion behaviors of Fe80Co3Si3B10P1C3 amorphous alloys in 1 mol/L NaCl solution were investigated by the electrochemical workstation. The pre-oxidation heat treatment can improve the corrosion resistance of FeCoSiBPC amorphous alloy through an increase in the Ecorr value from −0.736 to −0.668 V, which makes it easy to reach a passive state. The corroded morphology and products of amorphous alloys were tested by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM/TEM analysis showed that, after pre-oxidation treatment, the oxide layer was divided into two layers: the inner layer was amorphous, the outer layer appeared crystalline, and the main oxide was Fe2O3. During the oxidation process, Co and P elements diffused from the inner layer to the outer layer, forming phosphorus and cobalt oxides with high corrosion resistance on the surface of the ribbon, thereby improving the corrosion resistance of the ribbon.
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Investigation of Mechanical and Magnetic Properties of Co-Based Amorphous Powders Obtained by Atomization. MATERIALS 2021; 14:ma14237357. [PMID: 34885509 PMCID: PMC8658695 DOI: 10.3390/ma14237357] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 11/16/2022]
Abstract
Properties of Co-based alloys with high Glass Forming Ability (GFA) in the form of powder are still not widely known. However, powders of high GFA alloys are often used for the development of bulk metallic glasses by additive manufacturing. In this work Co47.6B21.9Fe20.4Si5.1Nb5% at. and Co42B26.5Fe20Ta5.5Si5Cu1% at. were developed by gas-atomization. Obtained powders in size 50-80 µm were annealed at Tg and Tx of each alloy. Then SEM observation, EDS analyses, differential thermal analysis, X-ray diffraction, nanoindentation, Mössbauer, and magnetic properties research was carried out for as-atomized and annealed states. The gas atomization method proved to be an efficient method for manufacturing Co-based metallic glasses. The obtained powder particles were spherical and chemically homogeneous. Annealing resulted in an increase of mechanical properties such as hardness and the elastic module of Co47.6B21.9Fe20.4Si5.1Nb5% at and Co42B26.5Fe20Ta5.5Si5Cu1%, which was caused by crystallization. The magnetic study shows that Co47.6B21.9Fe20.4Si5.1Nb5 and Co42B26.5Fe20Ta5.5Si5Cu1 are soft magnetic and semi-hard magnetic materials, respectively.
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Study on the Impact-Induced Energy Release Characteristics of Zr 68.5Cu 12Ni 12Al 7.5 Amorphous Alloy. MATERIALS 2021; 14:ma14061447. [PMID: 33809647 PMCID: PMC8002326 DOI: 10.3390/ma14061447] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/08/2021] [Accepted: 03/14/2021] [Indexed: 11/16/2022]
Abstract
As a new kind of multifunctional energetic structural material (MESM), amorphous alloy will undergo a chemical reaction and release energy under impact load. In this paper, an analysis method for the impact-induced reaction parameters of solid materials was derived based on a three-term equation of state and Avrami-Erofeev equation. The relation between the degree of reaction, pressure, and temperature of Zr68.5Cu12Ni12Al7.5 amorphous alloy was obtained. The influence of participation of an oxidizing reaction on the material energy release efficiency was analyzed. The relation between the energy release efficiency and impact velocity was achieved by an experiment in which Zr68.5Cu12Ni12Al7.5 amorphous alloy fragments impact a steel plate. The variations of pressure and temperature during the impact process were obtained. In the end, a reaction kinetic model was modified, and the kinetic parameters for the impact-induced reaction of materials in an air environment were obtained.
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Effect of Strain Rate on Compressive Behavior of a Zr-Based Metallic Glass under a Wide Range of Strain Rates. MATERIALS 2020; 13:ma13122861. [PMID: 32630616 PMCID: PMC7345190 DOI: 10.3390/ma13122861] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 11/17/2022]
Abstract
The strain rate effect on the mechanical behavior of amorphous alloys has aroused general interest. Most studies in this area have focused on quasi-static and high strain-rate compressive deformations. However, experimental results have been few, or even non-existent, under a moderate strain-rate loading. This article extends the traditional split Hopkinson pressure bar (SHPB) technique to characterize compressive deformation of an amorphous alloy at medium strain rates. The compressive behavior of Zr65.25Cu21.75Al8Ni4Nb1 amorphous alloy shows a negative strain rate effect on the yield strength with a quasi-static, moderate to high strain-rate range, and the fracture angle increases from 44° at 10−5 s−1 to 60° at 4000 s−1 as strain rate increases. Herein, we introduce a modified cooperative shear model to describe the compressive behavior of the current amorphous alloy under a broad strain rate range. The model predicts that the normalized yield strength will linearly descend with logarithmic strain rate when the strain rate is less than a critical strain rate, however, which rapidly decreases linearly with the square of the strain rate at high strain rates. The predicted data of the model are highly consistent with the current experimental results. These findings provide support for future engineering applications of amorphous alloys.
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Amorphous TiCu-Based Additives for Improving Hydrogen Storage Properties of Magnesium Hydride. ACS APPLIED MATERIALS & INTERFACES 2019; 11:38868-38879. [PMID: 31559817 DOI: 10.1021/acsami.9b16076] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Magnesium hydride has long been regarded as a promising candidate material for hydrogen and heat storage due to its high hydrogen capacity, reversibility, and low cost. Catalytic doping has been demonstrated as one of the most effective methods to improve hydrogen storage properties of MgH2. In this study, amorphous Ti45Cu41Ni9Zr5 and Ti40Cu47Zr10Sn3 alloys are used as additives for MgH2. Nanostructured MgH2 doped with amorphous or crystalline TiCu-based alloys are prepared by using a high-energy mechanochemical synthesis method. Results show that the amorphous TiCu additives provide enhanced catalytic effects compared to crystalline alloys of the same composition. Doping MgH2 using an amorphous Ti45Cu41Ni9Zr5 alloy yielded improved dehydrogenation kinetics compared to using crystalline Ti40Cu47Zr10Sn3 alloy. The analysis using transmission electron microscopy reveals that there are nanostructured catalytic particles uniformly distributed in the amorphous TiCu-catalyzed MgH2. The MgH2 system catalyzed by amorphous TiCu-based alloy shows little degradation during hydrogenation and dehydrogenation cycling at 300 °C. The amorphous TiCu-based catalysts are thermally stable at temperatures up to 360 °C. Heating the amorphous Ti45Cu41Ni9Zr5-catalyzed MgH2 to temperatures above 360 °C led to disproportionation of the catalyst alloy and the formation of MgCu2 and Ti2Cu. In addition, PCI analysis of the amorphous Ti45Cu41Ni9Zr5-catalyzed MgH2 shows a slight increase in hydrogen equilibrium pressure, resulting in a reaction enthalpy of -78.7 kJ/mol·H2 and an entropy of 145.0 J/K·mol·H2. The entropy calculated from this study is approximately 10 J/K·mol·H2 higher than values previously reported for undoped and catalyzed Mg-H systems.
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Tensductor- Amorphous Alloy Based Magnetoelastic Tensile Force Sensor. SENSORS 2018; 18:s18124420. [PMID: 30558113 PMCID: PMC6308646 DOI: 10.3390/s18124420] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 12/07/2018] [Accepted: 12/12/2018] [Indexed: 11/25/2022]
Abstract
In this paper new, tensile force sensor is presented, based on Pressductor topology and single layer of ferromagnetic amorphous ribbon. Simplified operating principle of the magnetic core with orthogonal coils is described. Straight and diagonal cut sensors are compared. The load vs. induced voltage characteristics are presented, as well as possibility of higher harmonics utilization. The effect of supply current on signal amplitude and measurement hysteresis is given. The developed ‘Tensductor’ sensor has near-linear characteristics and is relatively easy to manufacture. The measurement range is scalable, the experimental unit had 0–12 N measurement range with 1% accuracy, mostly due to magnetoelastic hysteresis.
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Estimation of Residual Stress in Selective Laser Melting of a Zr-Based Amorphous Alloy. MATERIALS 2018; 11:ma11081480. [PMID: 30127268 PMCID: PMC6120054 DOI: 10.3390/ma11081480] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 08/11/2018] [Accepted: 08/17/2018] [Indexed: 11/17/2022]
Abstract
An accurate estimation of residual stresses is crucial to ensure dimensional accuracy and prevent premature fatigue failure of 3D printed components. Different from their crystalline counterparts, the effect of residual stress would be worse for amorphous alloys owing to their intrinsic brittleness with low fracture toughness. However, the generation of residual stress and its performance in 3D printed amorphous alloy components still remain unclear. Here, a finite element method combined with experiments and theoretical analyses was introduced to estimate the residual stress in selective laser melting of a Zr-based amorphous alloy. The results revealed that XY cross scanning strategy exhibits relatively low residual stress by comparison with X and Y strategies, and the residual stress becomes serious with increasing bar thickness. The residual stress, on the other hand, could be tuning by annealing or preheating the substrate. The above scenario is thoroughly understood according to the temperature gradient mechanism and its effect on microstructure evaluation.
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Deformation-driven catalysis of nanocrystallization in amorphous Al alloys. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:1428-1433. [PMID: 27826517 PMCID: PMC5082720 DOI: 10.3762/bjnano.7.134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/16/2016] [Indexed: 06/06/2023]
Abstract
Nanocrystals develop in amorphous alloys usually during annealing treatments with growth- or nucleation-controlled mechanisms. An alternative processing route is intense deformation and nanocrystals have been shown to develop in shear bands during the deformation process. Some controversy surrounded the idea of adiabatic heating in shear bands during their genesis, but specific experiments have revealed that the formation of nanocrystals in shear bands has to be related to localized deformation rather than thermal effects. A much less debated issue has been the spatial distribution of deformation in the amorphous alloys during intense deformation. The current work examines the hypothesis that intense deformation affects the regions outside shear bands and even promotes nanocrystal formation in those regions upon annealing. Melt-spun amorphous Al88Y7Fe5 alloy was intensely cold rolled. Microcalorimeter measurements at 60 °C indicated a slight but observable growth of nanocrystals in shear bands over the annealing time of 10 days. When the cold-rolled samples were annealed at 210 °C for one hour, transmission electron images did not show any nanocrystals for as-spun ribbons, but nanocrystals developed outside shear bands for the cold rolled samples. X-ray analysis indicated an increase in intensity of the Al peaks following the 210 °C annealing while the as-spun sample remained "X-ray amorphous". These experimental observations strongly suggest that cold rolling affects regions (i.e., spatial heterogeneities) outside shear bands and stimulates the formation of nanocrystals during annealing treatments at temperatures well below the crystallization temperature of undeformed ribbons.
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Abstract
A high-resolution compositional map of glass-forming ability (GFA) in the Ni-Cr-Nb-P-B system is experimentally determined along various compositional planes. GFA is shown to be a piecewise continuous function formed by intersecting compositional subsurfaces, each associated with a nucleation pathway for a specific crystalline phase. Within each subsurface, GFA varies exponentially with composition, wheres exponential cusps in GFA are observed when crossing from one crystallization pathway to another. The overall GFA is shown to peak at multiple exponential hypercusps that are interconnected by ridges. At these compositions, quenching from the high-temperature melt yields glassy rods with diameters exceeding 1 cm, whereas for compositions far from these cusps the critical rod diameter drops precipitously and levels off to 1 to 2 mm. The compositional landscape of GFA is shown to arise primarily from an interplay between the thermodynamics and kinetics of crystal nucleation, or more precisely, from a competition between driving force for crystallization and liquid fragility.
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