349 results on '"cryomilling"'
Search Results
2. Production and characterisation of environmentally relevant microplastic test materials derived from agricultural plastics
- Author
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Hurley, Rachel, Binda, Gilberto, Briassoulis, Demetres, Carroccio, Sabrina Carola, Cerruti, Pierfrancesco, Convertino, Fabiana, Dvořáková, Darina, Kernchen, Sarmite, Laforsch, Christian, Löder, Martin G.L., Pulkrabova, Jana, Schettini, Evelia, Spanu, Davide, Tsagkaris, Aristeidis S., Vox, Giuliano, and Nizzetto, Luca more...
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- 2024
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Catalog
3. Phase composition and magnetic properties of SmCo5/Fe nanocomposite powder prepared by cryomilling
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Li, Bangzhen, An, Shizhong, Li, Wuhui, and Ren, Fengzhang
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- 2025
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4. The effect of PEO/NaCl dual porogens in the fabrication of porous PCL membranes via a solid-state blending approach.
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Allaf, Rula M.
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- *
PHYSICAL & theoretical chemistry , *POLYMERIC membranes , *HOT pressing , *CRYOGENIC grinding , *REGRESSION analysis - Abstract
In this investigation, the influence of a combination of poly(ethylene-oxide) (PEO) and salt (NaCl) as water-soluble porogens on the synthesis of sustainable porous poly(ε-caprolactone) (PCL) membranes is explored. Nine mixture compositions are examined. PCL sheets are fabricated through the cryomilling, hot pressing, and porogen leaching approach. The resulting sheets are investigated for their morphologies, porosities, water uptake, and mechanical properties. Thick sheets display a porous lamellar structure with porosities ranging from 47.4% to 70.8%. Lamellae exhibit various surface features ranging from smooth surfaces, rough with pinholes, globular, fibrillar, and finally skeletal structures. Higher salt contents result in more compact lamellae with higher interconnected porosities on the lamellae surfaces. Samples demonstrate significant water uptake, increasing with higher porosities, while mechanical properties decrease. Regression analysis is used to fit the mechanical properties of the thin sheets, revealing second order polynomial functions of porosity. Additionally, the sandwich method is successfully employed to create porous membrane surfaces, yielding various distinct morphologies, including a notable feather-like layered structure and a hierarchal particulate structure with large particles coated with aggregates of tiny particles. These findings contribute to understanding the synthesis and properties of sustainable porous polymer membranes, with implications for various applications. [ABSTRACT FROM AUTHOR] more...
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- 2025
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5. Enhancement in Mechanical Properties of Bulk Nanocrystalline Aluminum by Grain Boundary Strengthening Mechanism.
- Author
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Kushwaha, Amanendra K., Misra, Manoranjan, and Menezes, Pradeep L.
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CRYSTAL grain boundaries ,TRANSMISSION electron microscopy ,MICROHARDNESS testing ,SCANNING electron microscopy ,FATIGUE testing machines - Abstract
In the present work, commercially pure aluminum (Al) powders were milled at cryogenic temperatures (a) without magnesium (Mg) and (b) with 5 wt.% Mg powders for different durations. The cryomilled powders were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD) to determine the changes in particle morphology, elemental composition, and crystallite size. The results showed a reduction in crystallite size with the increase in cryomilling duration. Thereafter, the spark plasma sintering (SPS) process was carried out to manufacture bulk samples. The mechanical properties of the bulk SPS samples were assessed by conducting microhardness, tensile, and fatigue tests. The Vickers microhardness tests showed improved hardness for the Al-Mg bulk samples as compared to pure Al. The Al-Mg samples also showed an increase in tensile strength with increasing cryomilling time. Fatigue test results showed an improvement in Al-Mg components' high-cycle fatigue response. The mechanism for the enhancement in mechanical properties as a result of crystallite size reduction and grain boundary strengthening by the addition of Mg dopant is also discussed. [ABSTRACT FROM AUTHOR] more...
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- 2025
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6. Smart manufacturing approach to manufacture bulk nanocrystalline aluminum for lightweight applications.
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Kushwaha, Amanendra K., Misra, Manoranjan, and Menezes, Pradeep L.
- Subjects
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TRANSMISSION electron microscopy , *MICROHARDNESS testing , *SCANNING electron microscopy , *TENSILE tests , *CRYOGENIC grinding , *FRACTOGRAPHY - Abstract
In this research, a smart manufacturing approach was used to enhance the mechanical properties of aluminum (Al) for lightweight applications. The smart manufacturing involved cryomilling of Al powders with and without 5 wt.% magnesium (Mg) powders for varying durations followed by a high-pressure cold spray (HPCS) additive manufacturing process to prepare bulk components. The morphological changes, crystallite size, and composition of the cryomilled powders and cold sprayed (CS'ed) components were examined using scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The results showed that the crystallite size reduces with an increase in cryomilling time and the addition of Mg dopant. To test the mechanical properties of the bulk CS'ed components, microhardness tests were performed using a Vickers microhardness tester. Uniaxial tensile tests were also carried out to ascertain the material's tensile properties. The mechanical testing results showed great improvement in the hardness and tensile strength of CS'ed Al–Mg samples as compared to pure Al samples. Subsequently, fractography analysis of the tensile failed samples was carried out to determine the nature of the failure. The research article also discusses the inherent mechanisms for the improvement in mechanical properties of smart manufactured components as a result of Mg doping and cryomilling. [ABSTRACT FROM AUTHOR] more...
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- 2024
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7. Nanostructuring of AlSiCrMnFeNiCu High‐Entropy Alloy via Cryomilling: Exploring Structural, Magnetic, and Thermoelectric Properties.
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Shadangi, Yagnesh, Sherpa, Pema Chida, Jain, Harsh, Varalakshmi, S., Chatterji, Sandip, Ghosh, Labanya, Mukhopadhyay, Nilay Krishna, Tripathi, Ajay, and Tiwari, Archana
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MAGNETIC transitions ,MAGNETIC alloys ,THERMOELECTRIC materials ,ELECTRIC conductivity ,MAGNETIC measurements ,POWDERS - Abstract
Efforts are made to understand the influence of milling intensity on structure, morphology, magnetic and thermoelectric properties of nonequiatomic nanostructured AlSiCrMnFeNiCu high‐entropy alloy (HEA) powders prepared by cryomilling. These powders are cryomilled with different ball‐to‐powder ratios (BPR) and present a dual‐phase structure containing a major B2‐type and a minor Cr5Si3‐type phase. An increase in BPR enhances the refinement of crystallite size, grain size, and particle size accompanied by a decrease in the phase fraction of the minor Cr5Si3‐type phase. Magnetic measurements revealed that at room temperature, sufficient increase in BPR leads to a transition from multi‐domain behavior to single‐domain behavior which leads to enhancement in soft magnetic properties. Thermal measurements show the presence of different magnetic phase transitions which vary with an increase in BPR. A change of charge carrier type from p to n‐type was observed as the grain size is reduced. The figure of merit decreases with the decrease in grain size from 2 × 10–5 for as‐cast powders and is lowest for the smallest grain‐sized sample due to a decrease in electrical conductivity. This study shows the possibility of exploring nonequiatomic low‐density HEAs whose functional properties can be tailored, offering flexibility in material design for specific applications. [ABSTRACT FROM AUTHOR] more...
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- 2024
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8. Effect of Carbon Addition and Mechanical Activation on FeNi Alloys for Permanent Magnet Applications.
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da Silva, Valmir R., Fjellvåg, Øystein S., Pokle, Anuj, Hauback, Bjørn C., and Deledda, Stefano
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SCANNING transmission electron microscopy ,X-ray powder diffraction ,MAGNETIC properties ,LIQUID nitrogen ,CRYOGENIC grinding - Abstract
Tetrataenite is a promising candidate for rare earth-free permanent magnets due to its low cost and intrinsic magnetic properties. This work investigates the effect of combined milling at liquid nitrogen temperatures (cryomilling) and the addition of carbon as an interstitial element for promoting the formation of tetrataenite. Crystal structure, microstructure, and magnetic properties are investigated to understand the influence of mechanical processing and compositional modifications. No unambiguous evidence of the ordered phase of tetrataenite is found in the structural characterization. However, using Scanning Transmission Electron Microscopy (STEM) and powder X-ray diffraction (PXD) analyses, the occurrence of both twinning and stacking faults resulting from the high-energy milling process is observed, which is a relevant factor for identifying tetrataenite in FeNi alloys. The probability of a stacking fault and twinning occurring for a carbon-free FeNi sample before annealing is found to be 2% and 1.4%, respectively. After annealing, the stacking fault probability decreased to 1.2%, while that of twinning was 1.4%. By increasing the carbon concentration to 5 at.%, the stacking faults and twinning probabilities decrease slightly to 1.2% and 1.3%, respectively. The occurrence of stacking faults combined with small crystallite sizes was a hindering factor in identifying the presence of tetrataenite. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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9. Effect of Carbon Addition and Mechanical Activation on FeNi Alloys for Permanent Magnet Applications
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Valmir R. da Silva, Øystein S. Fjellvåg, Anuj Pokle, Bjørn C. Hauback, and Stefano Deledda
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cryomilling ,rare earth-free permanent magnets ,stacking faults ,tetrataenite ,magnetism ,Mining engineering. Metallurgy ,TN1-997 - Abstract
Tetrataenite is a promising candidate for rare earth-free permanent magnets due to its low cost and intrinsic magnetic properties. This work investigates the effect of combined milling at liquid nitrogen temperatures (cryomilling) and the addition of carbon as an interstitial element for promoting the formation of tetrataenite. Crystal structure, microstructure, and magnetic properties are investigated to understand the influence of mechanical processing and compositional modifications. No unambiguous evidence of the ordered phase of tetrataenite is found in the structural characterization. However, using Scanning Transmission Electron Microscopy (STEM) and powder X-ray diffraction (PXD) analyses, the occurrence of both twinning and stacking faults resulting from the high-energy milling process is observed, which is a relevant factor for identifying tetrataenite in FeNi alloys. The probability of a stacking fault and twinning occurring for a carbon-free FeNi sample before annealing is found to be 2% and 1.4%, respectively. After annealing, the stacking fault probability decreased to 1.2%, while that of twinning was 1.4%. By increasing the carbon concentration to 5 at.%, the stacking faults and twinning probabilities decrease slightly to 1.2% and 1.3%, respectively. The occurrence of stacking faults combined with small crystallite sizes was a hindering factor in identifying the presence of tetrataenite. more...
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- 2024
- Full Text
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10. An assessment of methods used for the generation and characterization of cryomilled polystyrene micro- and nanoplastic particles
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Campbell J. McColley, Jeffrey A. Nason, Bryan J. Harper, and Stacey L. Harper
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Microplastics ,Nanoplastics ,Cryomilling ,Particle sizing ,Polystyrene ,Environmental pollution ,TD172-193.5 ,Polymers and polymer manufacture ,TP1080-1185 - Abstract
Abstract There is a critical need to generate environmentally relevant microplastics (MPs) and nanoplastics (NPs) to better investigate their behavior in laboratory settings. Environmental MPs are heterogenous in size and shape, unlike monodisperse and uniform microspheres commonly used as surrogates. Cryogenic grinding, or cryomilling, was successfully utilized to transform polystyrene (PS) bulk material into heterogenous micro and nano fragments. Fourier-Transform Infrared (FTIR) spectroscopy confirmed that this approach did not alter polymer surface chemistry. The number of milling cycles (time of milling) and frequency of grinding (intensity of milling) were varied to investigate the role cryomilling parameters had on generated MP characteristics. The resulting particle size distributions of cryomilled samples were measured and compared. Coulter Counter and Nanoparticle Tracking Analysis (NTA) were used to measure the particle size distributions at the micro and nanoparticle size ranges, respectively. Microspheres were used to determine what camera settings yielded more accurate sizing and to reduce bias in the NTA analysis. Increasing milling cycles generally increased the number of smaller particles. The evolution of the measured size distributions indicated that small nanosized fragments broke off from larger MPs during cryomilling, steadily eroding larger MP fragments. The number of milling cycles was observed to more consistently impact the size distributions of fragments compared to the frequency of milling. This study offers both analysis of the cryomilling process and recommendations for generating more realistic PS MP/NPs for examining environmental fate and effects. more...
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- 2023
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11. Solid-state blending for the preparation of porous eco-friendly PCL membranes: Potential for filtration applications.
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Allaf, Rula M and Futian, Mohammad
- Subjects
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WATER filtration , *MEMBRANE separation , *MANUFACTURING processes , *CONTACT angle , *POLYMERIC composites , *CRYOGENIC grinding , *HOT pressing , *POLYCAPROLACTONE - Abstract
Cryomilling is a promising method for fabricating polymeric blend and composite powder raw materials for various subsequent manufacturing processes. In this study, biodegradable porous membranes were fabricated from poly (ε-caprolactone) (PCL) using the cryomilling/hot pressing/porogen leaching approach. Powder mixtures of six different model compositions were compounded by cryomilling; thereafter, films were fabricated by hot-pressing. Poly (ethylene-oxide) (PEO) and salt were utilized as eco-friendly porogens in these mixtures, which were dissolved in water to introduce porosity in the films. Wood sawdust (WSD) and alum were investigated as fillers potentially capable of manipulating the hydrophilicity, mechanical and antimicrobial properties of the membranes. The morphological, hydrophilicity, mechanical, and filtration efficiency properties were explored and compared to those of commercial laboratory microfiltration (MF) membranes. SEM analysis revealed dense membrane skins for all compositions, along with lamellar porous structures. Mean pore radius ranged from 0.15 to 0.21 μm, which is within the MF pore size range. Water contact angle measurements averaged 70° and decreased with the addition of WSD and alum, indicating increased hydrophilicity. Tensile test results showed a decrease in mechanical properties, with higher porosities and with the addition of WSD. Adding alum (≥10 wt%) resulted in embrittled membranes. Filtration performance was evaluated in terms of pure water flux and turbidity reduction for textile wastewater, and it compared favorably to commercial membranes. In conclusion, this study has successfully introduced a new facile and versatile membrane fabrication approach. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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12. An assessment of methods used for the generation and characterization of cryomilled polystyrene micro- and nanoplastic particles.
- Author
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McColley, Campbell J., Nason, Jeffrey A., Harper, Bryan J., and Harper, Stacey L.
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POLYSTYRENE ,PARTICLE size distribution ,CRYOGENIC grinding ,NANOPARTICLE size ,NANOPARTICLES - Abstract
There is a critical need to generate environmentally relevant microplastics (MPs) and nanoplastics (NPs) to better investigate their behavior in laboratory settings. Environmental MPs are heterogenous in size and shape, unlike monodisperse and uniform microspheres commonly used as surrogates. Cryogenic grinding, or cryomilling, was successfully utilized to transform polystyrene (PS) bulk material into heterogenous micro and nano fragments. Fourier-Transform Infrared (FTIR) spectroscopy confirmed that this approach did not alter polymer surface chemistry. The number of milling cycles (time of milling) and frequency of grinding (intensity of milling) were varied to investigate the role cryomilling parameters had on generated MP characteristics. The resulting particle size distributions of cryomilled samples were measured and compared. Coulter Counter and Nanoparticle Tracking Analysis (NTA) were used to measure the particle size distributions at the micro and nanoparticle size ranges, respectively. Microspheres were used to determine what camera settings yielded more accurate sizing and to reduce bias in the NTA analysis. Increasing milling cycles generally increased the number of smaller particles. The evolution of the measured size distributions indicated that small nanosized fragments broke off from larger MPs during cryomilling, steadily eroding larger MP fragments. The number of milling cycles was observed to more consistently impact the size distributions of fragments compared to the frequency of milling. This study offers both analysis of the cryomilling process and recommendations for generating more realistic PS MP/NPs for examining environmental fate and effects. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
13. Cryomilling of Isotope-Enriched Ti Powders for HIVIPP Deposition to Manufacture Targets for Nuclear Cross Section Measurement.
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Cisternino, Sara, De Dominicis, Lucia, Mou, Liliana, Esposito, Juan, Gennari, Claudio, Calliari, Irene, and Pupillo, Gaia
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RADAR cross sections , *NUCLEAR cross sections , *NUCLEAR reactions , *CRYOGENIC grinding , *POWDERS , *METALLURGICAL analysis - Abstract
The realization of isotopically enriched Ti targets for nuclear cross-section measurements requires particular attention, from the starting material preparation up to the deposition technique. In this work, a cryomilling process was developed and optimized, aimed at reducing the size of 49,50Ti metal sponge as provided by the supplier (size up to 3 mm), to the optimal size of 10 µm, to fit the High Energy Vibrational Powder Plating technique used for target manufacturing. The optimization of the cryomilling protocol and the HIVIPP deposition using natTi material was thus performed. The scarce amount of the enriched material to be treated (about 150 mg), the need to obtain a non-contaminated final powder and a uniform target thickness of about 500 µg/cm2 were taken into account. The 49,50Ti materials were then processed and 20 targets of each isotope were manufactured. Both powders and the final Ti targets produced were characterized by SEM-EDS analysis. The amount of Ti deposited was measured by weighing, indicating reproducible and homogeneous targets, with an areal density of 468 ± 110 µg/cm2 for 49Ti (n = 20) and 638 ± 200 µg/cm2 for 50Ti (n = 20). The uniformity of the deposited layer was also confirmed by the metallurgical interface analysis. The final targets were used for the cross section measurements of the 49Ti(p,x)47Sc and 50Ti(p,x)47Sc nuclear reaction routes aimed at the production of the theranostic radionuclide 47Sc. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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14. Mechanical Particle-Size Reduction Techniques
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Morales, Javier O., Watts, Alan B., McConville, Jason T., Perrie, Yvonne, Series Editor, Williams III, Robert O., editor, Davis Jr., Daniel A., editor, and Miller, Dave A., editor
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- 2022
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15. Evidence of an unusual magnetic behavior at the morphotropic phase boundary of La doped BiFeO3 ceramics.
- Author
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Oliveira, Roger Carvalho, Volnistem, Eduardo Azzolini, dos Santos, Ivair Aparecido, Dias, Gustavo Sanguino, Cotica, Luiz Fernando, Eiras, José Antonio, and Garcia, Ducinei
- Subjects
- *
HYSTERESIS loop , *LEAD-free ceramics , *MORPHOTROPIC phase boundaries , *BISMUTH iron oxide , *CERAMICS , *MAGNETIZATION - Abstract
In this paper, Bi(1-x)LaxFeO3 ceramics were processed considering two compositions inside (Bi0.85La0.15FeO3) and outside (Bi0.95La0.05FeO3) the morphotropic phase boundary that separates the rhombohedral and orthorhombic phases. An unusual magnetic behavior, characterized by a double hysteresis loop, was observed at room temperature for the Bi0.85La0.15FeO3 sample. Langevin analyses revealed that this behavior is related to both the linear and non-linear components of the magnetization, indicating possible changes of the magnetic phase with doping. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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16. A high-Nb–TiAl alloy with ultrafine-grained structure fabricated by cryomilling and spark plasma sintering.
- Author
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Deng, Hao, Wei, Yong-Qiang, Tang, Jun, Chen, Ai-Jun, Chen, Long-Qing, and Xia, Zu-Xi
- Abstract
In this work, an ultrafine-grained high-Nb–TiAl alloy with a nominal composition of Ti–45Al–8Nb–0.2W–0.2B (at%) was prepared by cryomilling and subsequent spark plasma sintering (SPS) technique. The chemical composition, particle size, morphology and crystallite size of cryomilled powder were studied. It is found that cryomilling can effectively reduce the particle size and enhance grain refinement. The ingots sintered at 900 and 1000 °C show an equiaxed near-γ microstructure with grain sizes < 700 nm, while the sample sintered at 1100 °C exhibits duplex microstructure. Especially, the one sintered at 1000 °C has excellent mechanical properties, whose compression yield strength, fracture strength, bending strength and plastic strain achieve 1310, 2174, 578 MPa and 16.8%, respectively. The reasons for the effect of cryomilling and the mechanical behavior of sintered ingots were discussed. It is suggested that cryomilling in combination with SPS is an effective way to synthesize high-Nb–TiAl alloy with ultrafine-grained structure. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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17. Effect of Magnesium Dopant on the Grain Boundary Stability of Nanocrystalline Aluminum Powders during Cryomilling.
- Author
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Kushwaha, Amanendra K., Misra, Manoranjan, and Menezes, Pradeep L.
- Subjects
CRYSTAL grain boundaries ,CRYOGENIC grinding ,DOPING agents (Chemistry) ,ALUMINUM-magnesium alloys ,ALUMINUM powder ,MAGNESIUM ,TRANSMISSION electron microscopy - Abstract
In this investigation, pure aluminum (Al) powders were cryomilled with and without magnesium dopants to study (a) the effect of cryomilling time on the crystallite size and (b) the effect of magnesium dopant on Al to achieve grain boundary stability. The cryomilling process was carried out using liquid nitrogen for different durations. The characterization of the cryomilled powders was carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) to understand the particle morphology, crystallite size, and elemental composition. The results demonstrated that the size of the crystallites in both Al and Mg-doped Al powders reduces as the cryomilling duration increases. The results also indicated that the preferential segregation of Mg dopant at the grain boundaries of Al provides stability to the cryomilled powders at elevated temperatures. This article discusses the mechanism for the changes in crystallite size and the effect of the Mg dopant on the grain boundary stability in Al powders. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
18. Enhanced ionic conductivity of sulfide solid electrolyte with high lithium content based on cryomilling
- Author
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Zhenggang Jia, Xuexi Zhang, Mingfang Qian, Yingmin Jin, and Yueping Xiong
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Sulfide solid electrolyte ,Solid-state battery ,Cryomilling ,Industrial electrochemistry ,TP250-261 ,Chemistry ,QD1-999 - Abstract
Considering the high ion conductivity and good machining properties of lithium thiophosphate (LPS), it has attracted increasing attention as a solid electrolyte for all-solid-state batteries. Chemical and thermal stability can be significantly enhanced by increasing lithium content. However, in past reports, the lithium content of LPS is commonly less than 40 %. LPS with high lithium content (Li > 40 at%) shows low ion conductivity and high grain boundary resistance. In the present work, LPS with 47.2 at% lithium was prepared by cryomilling and solid-state reaction, avoiding crystallization and adhesion in the ball milling process. By improving the ball milling process, the ion conductivity (1.36 mS/cm) and ion activation energy (10.80 kJ/mol) were optimized by 106.1 % and 41.5 %, respectively. The resulting all-solid-state battery showed a high capacity retention of 104 % after 100 cycles. more...
- Published
- 2023
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19. Manufacturing Bulk Nanocrystalline Al-3Mg Components Using Cryomilling and Spark Plasma Sintering.
- Author
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Kushwaha, Amanendra K., Misra, Manoranjan, and Menezes, Pradeep L.
- Subjects
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POWDERS , *CRYOGENIC grinding , *SCANNING transmission electron microscopy , *ALUMINUM-magnesium alloys , *SINTERING , *SCANNING electron microscopy - Abstract
In the current study, pure aluminum (Al) powders were cryomilled with and without 3 wt.% pure magnesium (Mg) dopant for varying durations followed by spark plasma sintering (SPS) of powders to prepare bulk components with superior mechanical properties. The crystallite sizes were determined for powders and the bulk components by analyzing the X-ray diffraction (XRD) spectrum. The calculations indicated a reduction in crystallite size with the increase in the cryomilling duration. The results also showed a more significant decrease in the crystallite sizes for Al-3Mg samples than that of pure Al. The changes in the surface morphology of powders were characterized using scanning electron microscopy (SEM). The elemental mapping analysis at nanoscale was carried out using Energy-dispersive X-ray spectroscopy (EDX) in Scanning transmission electron microscopy (STEM). The mechanical properties of the bulk components were assessed using a Vickers Microhardness tester. The test results demonstrated an improvement in the hardness of Mg-doped components. Higher hardness values were also reported with an increase in the cryomilling duration. This article discusses the mechanisms for the reduction in crystallite size for pure Al and Al-3Mg and its subsequent impact on improving mechanical properties. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
- Full Text
- View/download PDF
20. Microplastics for Use in Environmental Research.
- Author
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Tewari, Arundhati, Almuhtaram, Husein, McKie, Michael J., and Andrews, Robert C.
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PLASTIC marine debris ,MICROPLASTICS ,SOLUTION (Chemistry) ,PLASTICS ,MARINE debris ,POLYETHYLENE terephthalate ,ENVIRONMENTAL reporting - Abstract
Microplastics < 20 μm are being increasingly reported in treated drinking water as well as in surface waters. As such, ongoing microplastic-related research in various fields is beginning to focus on smaller particle sizes as these appear to be most important from a human health perspective. However, no standardized methods for preparing microplastics of this size have been reported in the literature. This study proposes a cryomilling-based method for preparing microplastics to be used in aqueous stock suspensions. Polymers of 22 different types were obtained from the Centre for Marine Debris Research, Hawai'i Pacific University. Polymers were produced that ranged in size from 2 to 125 μm of which 98% were classified as fragments with 2% as fibers. Size distributions for polyethylene terephthalate (PET) and polypropylene (PP), which are frequently reported in environmental samples, were determined using microscopy. Approximately 80% of the particles resulting from cryomilling were < 20 μm long (major dimension). A stock suspension prepared using PET was employed to illustrate and assess recovery for sampling equipment which incorporated in-line filtration. Recoveries exceeding 80% were observed for individual particle sizes ranging from 2 to 45 μm. Results of these trials suggest that stock suspensions of microplastics are heterogeneous and cannot be treated in a similar manner to chemical solutions. In conclusion, this study represents a forward step towards harmonization of environmental microplastic research methods and improving comparability of future studies. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
- Full Text
- View/download PDF
21. Effect of nanostructure on phase transformations during heat treatment of 2024 aluminum alloy
- Author
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K. B. Demétrio, A.P. G. Nogueira, C. Menapace, T. Bendo, and A. Molinari
- Subjects
Cryomilling ,2024 Al alloy ,Nanostructured ,Thermal stability ,Artificial aging ,Phase transformation ,Mining engineering. Metallurgy ,TN1-997 - Abstract
In this work, we studied the transformations involving the coherent (θ”/S”), semicoherent (θ’/S’), and incoherent (θ/S) precipitates (θ = Al2Cu, S = Al2CuMg) formed during the heat treatment of an annealed nanostructured powder of Al 2024 produced by cryogenic milling. These precipitates form over a wide temperature range (300–500 °C) depending on the chemical composition. They influence grain growth during sintering and may facilitate the formation of a fully dense nanostructured material. Mechanical milling was performed for 20 h at a cryogenic temperature to obtain nanostructured particles. The structural evolution and morphology of the particles during the heat treatment were investigated for three particle size ranges ( more...
- Published
- 2021
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22. Enhanced Reactivity and Compound Mechanism of Mg/B Composite Powders Prepared by Cryomilling.
- Author
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Zhang, Chi, Wang, Qin, Tang, Liying, and Chen, Fei
- Subjects
- *
POWDERS , *CRYOGENIC grinding , *RAW materials , *SURFACE structure , *ENERGY density - Abstract
Boron is one of the highest energy density materials. The heat of boron is difficult to carry out due to its poor combustion performance. Magnesium (10 wt.%), acting as combustion adjuvant, is added into boron powder to improve the combustion performance. In this study, two kinds of boron powder were used as raw material, boron powder with an average size of 40 μm is named B1, and B2 has an average powder size of 3 μm. Mg/B composite powder was prepared though a cryomilling method. Two compound mechanisms for Mg/B composite powder were applied. For Mg/B1 composite powder, an Mg-coating structure on the surface of B was generated. For Mg/B2, a structure that small particles were agglomerated with Mg in the interior or on the surface of B was generated. Compared with either B powder or blended Mg/B powder, the reactivity of Mg/B composite powder by cryomilling is enhanced. In addition, the atomic ratio of Mg to B and activity content of Mg on the surface of Mg/B composite powder have great impacts on the improvement of reactivity. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
- Full Text
- View/download PDF
23. Effect of Magnesium Dopant on the Grain Boundary Stability of Nanocrystalline Aluminum Powders during Cryomilling
- Author
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Amanendra K. Kushwaha, Manoranjan Misra, and Pradeep L. Menezes
- Subjects
nanocrystalline aluminum ,magnesium ,cryomilling ,characterization ,thermal stability ,sintering ,Crystallography ,QD901-999 - Abstract
In this investigation, pure aluminum (Al) powders were cryomilled with and without magnesium dopants to study (a) the effect of cryomilling time on the crystallite size and (b) the effect of magnesium dopant on Al to achieve grain boundary stability. The cryomilling process was carried out using liquid nitrogen for different durations. The characterization of the cryomilled powders was carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) to understand the particle morphology, crystallite size, and elemental composition. The results demonstrated that the size of the crystallites in both Al and Mg-doped Al powders reduces as the cryomilling duration increases. The results also indicated that the preferential segregation of Mg dopant at the grain boundaries of Al provides stability to the cryomilled powders at elevated temperatures. This article discusses the mechanism for the changes in crystallite size and the effect of the Mg dopant on the grain boundary stability in Al powders. more...
- Published
- 2023
- Full Text
- View/download PDF
24. Sampling Procedure, Characterization, and Quantitative Analyses of Industrial Aluminum White Dross
- Author
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Solem, Cathrine Kyung Won, Deledda, Stefano, Tranell, Gabriella, and Aune, Ragnhild E.
- Published
- 2023
- Full Text
- View/download PDF
25. Hydrogen sorption characteristics of nanostructured Pd–10Rh processed by cryomilling
- Author
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San Marchi, Chris [Sandia National Lab. (SNL-CA), Livermore, CA (United States)]
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- 2014
- Full Text
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26. Correlation between Microstructure and Exothermic Reaction Kinetics of Al-CuO Thermite Nanocomposite Powders Fabricated by Cryomilling
- Author
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Minseok Oh, Kwanil Kim, and Byungmin Ahn
- Subjects
al-cuo ,thermite ,nanocomposite ,cryomilling ,high energy density materials ,Mining engineering. Metallurgy ,TN1-997 ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Al-CuO is a thermite material exhibiting the exothermic reaction only when aluminum melts. For wide spread of its application, the reaction temperature needs to be reduced in addition to the enhancement of total reaction energy. In the present study, a thermite nanocomposite with a large contact area between Al and CuO was fabricated in order to lower the exothermic reaction temperature and to improve the reactivity. A cryomilling process was performed to achieve the nanostructure, and the effect of composition on the microstructure and its reactivity was studied in detail. The microstructure was characterized using SEM and XRD, and the thermal property was analyzed using DSC. The results show that as the molar ratio between Al and CuO varies, the fraction of uniform nanocomposite structure was changed affecting the exothermic reaction characteristics. more...
- Published
- 2019
- Full Text
- View/download PDF
27. La doped BiFeO3 ceramics synthesized under extreme conditions: Enhanced magnetic and dielectric properties.
- Author
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Oliveira, Roger C., Volnistem, Eduardo A., Astrath, Eduardo A.C., Dias, Gustavo S., Santos, Ivair A., Garcia, Ducinei, and Eiras, José A.
- Subjects
- *
DIELECTRIC properties , *MAGNETIC properties , *CERAMICS , *CERAMIC powders , *CRYOGENIC grinding , *LEAD-free ceramics - Abstract
Multiferroic Bi 0.85 La 0.15 FeO 3 powders and ceramics were synthesized under extreme conditions by a combination of high-energy ball cryomilling, fast firing and spark plasma sintering procedures. Single-phased and perovskite structured samples, where both rhombohedral (R3c space group) and orthorhombic (Pnma) phases coexist, were successfully processed. Highly dense (7.92 g/cm3, 97.5% of the theoretical one) and electrically resistive (2.19 × 10 11 Ω ⋅ c m) nano-structured ceramics with high internal micro-strain levels (up to 1.08%), small crystallite size (24 nm) and elevated magnetization (ranging from 0.204 to 0.350 e m u / g at 15 kOe) with an expressive non-linear response were obtained by combining cryomilling, SPS and oxidative annealing. Particularly, the dielectric response is improved by oxidative annealing at 200 °C, reaching 170 at 1 kHz with very low loss tangent (2.5%). This study demonstrated the effectiveness of the chosen synthesis route in the production of BFO-based ceramics with enhanced ferroic properties. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
- Full Text
- View/download PDF
28. Cryogenic mechanical alloying of aluminum matrix composites for powder bed fusion additive manufacturing.
- Author
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Hamilton, Jakob D, Ramesh, Srikanthan, Harrysson, Ola LA, Rock, Christopher D, and Rivero, Iris V
- Subjects
- *
ALUMINUM composites , *MECHANICAL alloying , *ALUMINUM alloying , *PARTICLE size distribution , *POWDERS , *METAL powders , *POWDER metallurgy - Abstract
Cryogenic mechanical alloying (cryomilling) was employed to fabricate aluminum matrix composite powder feedstock for additive manufacturing. The high energy milling of the powder system induces a homogenous distribution of reinforcement particles in the matrix powder by recurrent fracture and cold welding. In this study, aluminum matrix composite feedstock were produced via different cryomilling techniques at varying compositions, powder charges, and milling times. As-milled powders were characterized for particle size distribution, morphology, and homogeneity. Resultant powder demonstrated varying characteristics correlated to milling parameters. Powder metallurgy samples were also fabricated to understand as-sintered reinforcement distribution and the resultant strengthening. This research provides an indication of cryomilling capabilities to become an effective method for custom alloy powder production for powder bed fusion additive manufacturing. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
- Full Text
- View/download PDF
29. Micrograin Superplasticity: Characteristics and Utilization.
- Author
-
Mohamed, Farghalli
- Subjects
cavitation ,cryomilling ,dislocation activity ,ductility ,grain boundary sliding ,high-strain rate superplasticity ,impurity effect ,micrograin superplasticity ,nanocrystalline materials - Abstract
Micrograin Superplasticity refers to the ability of fine-grained materials (1 µm < d < 10 μm, where d is the grain size) to exhibit extensive neck-free elongations during deformation at elevated temperatures. Over the past three decades, good progress has been made in rationalizing this phenomenon. The present paper provides a brief review on this progress in several areas that have been related to: (a) the mechanical characteristics of micrograin superplasticity and their origin; (b) the effect of impurity content and type on deformation behavior, boundary sliding, and cavitation during superplastic deformation; more...
- Published
- 2011
30. Quantitative Analysis of Cryomilled Nanocrystalline Ti-6Al-4V Alloy Powder by X-Ray Diffraction
- Author
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M. Oh, H.K. Yu, J.-H. Lee, M.C. Oh, S.-H. Jung, and B. Ahn
- Subjects
nanocrystalline ,cryomilling ,ti alloy ,x-ray diffraction ,size-strain plot method ,Mining engineering. Metallurgy ,TN1-997 ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
A nanocrystalline Ti alloy powder was fabricated using cryomilling. The grain size and lattice strain evolution during cryomilling were quantitatively analyzed using X-ray diffraction (XRD) based on the Scherrer equation, Williamson-Hall (W-H) plotting method, and size-strain (S-S) method assuming uniform deformation. Other physical parameters including stress and strain have been calculated. The average crystallite size and the lattice strain evaluated from XRD analysis are in good agreement with the result of transmission electron microscopy (TEM). more...
- Published
- 2018
- Full Text
- View/download PDF
31. Preparation of Nickel Powders by Reduction of Nickel Hydroxide Usingthe Taylor Fluid Flow
- Author
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I.-J. Park, D.-W. Kim, G.-H. Kim, H.-J. Chae, and S.-H. Jung
- Subjects
nanocrystalline ,cryomilling ,ti alloy ,x-ray diffraction ,size-strain plot method ,Mining engineering. Metallurgy ,TN1-997 ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
A nanocrystalline Ti alloy powder was fabricated using cryomilling. The grain size and lattice strain evolution during cryomilling were quantitatively analyzed using X-ray diffraction (XRD) based on the Scherrer equation, Williamson-Hall (W-H) plotting method, and size-strain (S-S) method assuming uniform deformation. Other physical parameters including stress and strain have been calculated. The average crystallite size and the lattice strain evaluated from XRD analysis are in good agreement with the result of transmission electron microscopy (TEM). more...
- Published
- 2018
- Full Text
- View/download PDF
32. Effect of Cryomilling on Microstructure and Mechanical Properties of 7050 Aluminum Alloy
- Author
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ZHANG Haiping, WANG Xudong, LI Jiongli, HE Tianbing, CAO Zhen, and CHEN Junzhou
- Subjects
powder metallurgy ,cryomilling ,7050 aluminum alloy ,mechanical property ,Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
The 7050 aluminum alloy samples were prepared from as-atomized 7050 aluminum alloy powder through cryomilling, hot isostatic pressing, hot extrusion and T6 heat treatment. The influence of cryomilling on morphology, grain size and microscopic strain of aluminum alloy powder were analyzed by SEM and XRD. The influence of cryomilling on microstructure and mechanical property of the sample after heat treatment was analyzed by OM, EBSD, TEM, XRD, microhardness and tensile test. The results show that cryomilling can effectively refine the grain size of the material and increase the number of nano-precipitates in the matrix. Compared to the as-atomized powder, the mechanical properties of the 7050 aluminum alloy sample prepared by cryomillied powder are obviously improved. more...
- Published
- 2018
- Full Text
- View/download PDF
33. Thermal Stability of Cryomilled Mg Alloy Powder
- Author
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Guan, Dikai, Mark Rainforth, W., Sharp, Joanne, Gao, Junheng, Solanki, Kiran N., editor, Orlov, Dmytro, editor, Singh, Alok, editor, and Neelameggham, Neale R., editor
- Published
- 2017
- Full Text
- View/download PDF
34. Catalytic activity of novel thermoplastic/cellulose-Au nanocomposites prepared by cryomilling.
- Author
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KWICZAK-YİĞİTBAŞI, Joanna
- Subjects
- *
NANOCOMPOSITE materials , *CATALYTIC activity , *CRYOGENIC grinding , *GOLD nanoparticles , *X-ray photoelectron spectroscopy , *THERMOPLASTICS , *BIOPOLYMERS , *THERMOPLASTIC composites - Abstract
Due to environmental concerns, increasing attention has been focused on the application and preparation of biobased polymers and their blends. In this study, cellulose, the most spread biopolymer on Earth, was used in the preparation of novel cotton/polypropylene- Au and cotton/polyethylene-Au nanocomposites via a green mechanochemical approach. First, mechanoradicals were generated by ball milling of the cotton and thermoplastics under cryo conditions, and then, these radicals were used in the reduction of Au ions to Au nanoparticles (Au NPs). Nanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The application of mechanochemistry in obtaining the cotton/thermoplastic blends allowed homogenous and fine blending of the samples and in addition, excluded the usage of toxic solvents. Since Au NPs exhibit a wide range of applications, e.g., in catalysis, cotton/thermoplastic-Au nanocomposites were used to catalyze the reduction reaction of 4-nitrophenol to 4-aminophenol, followed by UV-Vis spectroscopy. Finally, the hydrophobicity of the nanocomposites was alternated by tuning the blend composition. In the prepared nanocomposites, cotton and thermoplastics acted as very good supporting matrices for the Au NPs and provided satisfactory access to the NPs. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
- Full Text
- View/download PDF
35. Cryomilling-assisted high purity β-chitin extraction from Uroteuthis edulis pens.
- Author
-
Kim, Joong-Kwon, Song, Myeong-Oh, Kim, Jihye, Kim, Seoi, and Jin, Jungho
- Subjects
- *
CHITIN , *CRYOGENIC grinding , *OPTICAL films , *SQUIDS , *RAW materials , *ACETYLATION - Abstract
We report on the extraction of β-chitin from pens (or Gladius) of Uroteuthis edulis , a squid species prevalent in the Pacific coastal regions of East Asia. In particular, we employ cryogenic mechanical grinding (or cryomilling) as a pre-treatment process for the raw squid pens. We show that the cryomilling step enables an effective pulverization of the raw materials, which facilitates the removal of protein residues allowing the extraction of high-purity β-chitin with a high acetylation degree (∼97 %) and crystallinity (∼82 %). We also demonstrate that the Uroteuthis edulis extract β-chitin affords a free-standing film with excellent optical transmittance and mechanical properties. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
36. Influence of Cryomilling on Crystallite Size of Aluminum Powder and Spark Plasma Sintered Component
- Author
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Amanendra K. Kushwaha, Raven Maccione, Merbin John, Sridhar Lanka, Manoranjan Misra, and Pradeep L. Menezes
- Subjects
nanocrystalline aluminum ,cryomilling ,spark plasma sintering ,synthesis ,characterization ,microstructures ,Chemistry ,QD1-999 - Abstract
The present investigation aims to develop nanocrystalline (NC) pure aluminum powders using cryomilling technique and manufacture bulk components using spark plasma sintering (SPS). The cryomilling was performed on pure Al powders for 2, 6, and 8 h. The cryomilled powders were then consolidated using SPS to produce bulk components. The particle morphology and crystallite size of the powders and the bulk SPS components were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results showed that the crystallite size of pure Al powders decreases with increased cryomilling time. The results also showed that the SPS at elevated temperatures resulted in a slight increase in crystallite size, however, the changes were insignificant. The mechanical properties of the bulk components were determined using a Vickers microhardness tester. The hardness of the cryomilled SPS component was determined to be three times higher than that of the unmilled SPS component. The mechanism for the reduction in crystallite size with increasing cryomilling time is discussed. This fundamental study provides an insight into the development of bulk nanomaterials with superior mechanical properties for automotive, aerospace, marine, and nuclear applications. more...
- Published
- 2022
- Full Text
- View/download PDF
37. Mechanical Particle-Size Reduction Techniques
- Author
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Morales, Javier O., Watts, Alan B., McConville, Jason T., Crommelin, Daan J. A., Editor-in-chief, Lipper, Robert A., Editor-in-chief, Williams III, Robert O., editor, Watts, Alan B., editor, and Miller, Dave A., editor more...
- Published
- 2016
- Full Text
- View/download PDF
38. Strain Hardening, Strain Softening and the Portevin-Le Chatelier Effect in Cryomilled, Ultrafine Grained AA 5083
- Author
-
Topping, Troy D., Lavernia, Enrique J., Weiland, Hasso, editor, Rollett, Anthony D., editor, and Cassada, William A., editor
- Published
- 2016
- Full Text
- View/download PDF
39. Effect of Process Control Agent on the Microstructure and Mechanical Behavior of an Aluminum and B4C Metal Matrix Composite
- Author
-
Hofmeister, C., Giri, A., Brennan, S., Sohn, Y. H., Delahanty, T., Cho, K., and Grandfield, John, editor
- Published
- 2016
- Full Text
- View/download PDF
40. Nanocrystalline Materials: Synthesis, Characterization, Properties, and Applications
- Author
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Amanendra K. Kushwaha, Merbin John, Manoranjan Misra, and Pradeep L. Menezes
- Subjects
nanocrystalline materials ,cryomilling ,characterization ,synthesis ,mechanical properties ,microstructures ,Crystallography ,QD901-999 - Abstract
Nanostructuring is a commonly employed method of obtaining superior mechanical properties in metals and alloys. Compared to conventional polycrystalline counterparts, nanostructuring can provide remarkable improvements in yield strength, toughness, fatigue life, corrosion resistance, and hardness, which is attributed to the nano grain size. In this review paper, the current state-of-the-art of synthesis methods of nanocrystalline (NC) materials such as rapid solidification, chemical precipitation, chemical vapor deposition, and mechanical alloying, including high-energy ball milling (HEBM) and cryomilling was elucidated. More specifically, the effect of various process parameters on mechanical properties and microstructural features were explained for a broad range of engineering materials. This study also explains the mechanism of grain strengthening using the Hall-Petch relation and illustrates the effects of post-processing on the grain size and subsequently their properties. This review also reports the applications, challenges, and future scope for the NC materials. more...
- Published
- 2021
- Full Text
- View/download PDF
41. Nanoscaled Lithium Powders with Protection of Ionic Liquid for Highly Stable Rechargeable Lithium Metal Batteries
- Author
-
Kaichao Pu, Xiaolei Qu, Xin Zhang, Jianjiang Hu, Changdong Gu, Yongjun Wu, Mingxia Gao, Hongge Pan, and Yongfeng Liu
- Subjects
anode materials ,batteries ,cryomilling ,energy materials ,lithium metal ,Science - Abstract
Abstract To suppress the dendrite formation and alleviate volume expansion upon striping/platting is a key challenge for developing practical lithium metal anodes. Lithium metal in powder form possesses great potential to address this issue due to large specific surface area. However, the fabrication of powdery metallic lithium is largely restricted because of its unique softness, stickiness, and high reactivity. Here, a safe and readily accessible cryomilling process toward lithium powders is reported. Nanoscaled lithium powders ( more...
- Published
- 2019
- Full Text
- View/download PDF
42. PlasticsFatE Deliverable Report D1.1 Report on selected MP/NP and basic Physico Chem features
- Author
-
Costa, Anna Luisa, Altman, Korinna, Barbato, Francesco, and Portela, Raquel
- Subjects
characterisation ,Physicochemical ,microplastics ,cryomilling ,human health ,nanoplastics - Abstract
The deliverable D1.1 addressed some of the specific objectives of Task 1.1, as summarised below: 1. To select a set of relevant MP/NP to maximise the impact ofPlasticsfatecovering as much aspossible the compositional/morphological classes of micro-nano plastics (MP/NP) commonly spreadinto food, drinking and environmental matrices. 2. To generate and store a bank of relevant reference and/or certified, well-characterisedmicro-nano plastics (MP/NP) covering the identified classes for use inPlasticsfateand for future projectsthatwillcharacteriseor develop strategies to mitigate MP/NP pollution. 3. To develop standardized protocol for how to handle,characterize, store and distribute MP/NP. 4. To facilitate particles labelling, traceability and detection by means of fluorescent markers. In response to specific objective 1, it was established at portfolio (1st Tier) ofPlasticsfateMP/NPmaterials, differing for polymer type, source/size, use scenarios, it was agreed the code for theirclassificationand they were distributed to partners for the characterisation. In response to specific objective 2, BAMwas in charge ofthe creation ofPlasticsfatesamplesrepository, including some primary plastics, some commercial samples and some secondary particles,obtained by BAM throughcryomilling/aging treatments. The samples were checked by BAM andISTEC through dynamic imaging and optical or electronic microscope characterisation. The endotoxincontamination was tested by GAIKER (a partner from WP3), confirming that secondary PE, PETparticles and HDPE commercial sample (CeridustfromCariant) were not affected by endotoxincontamination. In response to specific objective 3, BAM developed and tested protocols for plastics milling andweathering; ISTEC-CNR and UNITO carried out an intensedispersabilitystudyin order toidentifydispersion protocols suitable for characterisation in WP1-3. A two-step process was selected, ageneral protocol for the preparation of stock dispersions and specific dispersants for the dilution ofstock dispersions in relevant simulant fluids (work dispersions). In response to specific objective 4, CSICcharacterisedLa-Eu doped PS nanoparticles purchased anddistributed by STAMI. Traceability was investigated by Raman-luminescence mapping. The results from D1.1. were shared/disseminated through the participation atCUSPchannels/events/workshops, where Task 1.1 partners are involved: Anna Costa/MagdaBlosirepresentatives forPlasticsfatein WG1 (Analytical methods and representative materials) andKorinnaAltmann/DanHodoraba, as coordinator of WG3 (Inter-laboratory comparisons). more...
- Published
- 2023
- Full Text
- View/download PDF
43. Diversification of CORVET tethers facilitates transport complexity in Tetrahymena thermophila.
- Author
-
Sparvoli, Daniela, Zoltner, Martin, Chao-Yin Cheng, Field, Mark C., and Turkewitz, Aaron P.
- Subjects
- *
TETRAHYMENA , *LANDFILLS , *TRAFFIC incident management - Abstract
In endolysosomal networks, two hetero-hexameric tethers called HOPS and CORVET are found widely throughout eukaryotes. The unicellular ciliate Tetrahymena thermophila possesses elaborate endolysosomal structures, but curiously both it and related protozoa lack the HOPS tether and several other trafficking proteins, while retaining the related CORVET complex. Here, we show that Tetrahymena encodes multiple paralogs of most CORVET subunits, which assemble into six distinct complexes. Each complex has a unique subunit composition and, significantly, shows unique localization, indicating participation in distinct pathways. One pair of complexes differ by a single subunit (Vps8), but have late endosomal versus recycling endosome locations. While Vps8 subunits are thus prime determinants for targeting and functional specificity, determinants exist on all subunits except Vps11. This unprecedented expansion and diversification of CORVET provides a potent example of tether flexibility, and illustrates how 'backfilling' following secondary losses of trafficking genes can provide a mechanism for evolution of new pathways. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
- Full Text
- View/download PDF
44. Characterization investigations of the mechanically alloyed and sequentially milled Al-12.6 wt.% Si eutectic alloy powders.
- Author
-
Tekoğlu, Emre, Ağaoğulları, Duygu, and Lütfi Öveçoğlu, M.
- Subjects
- *
EUTECTIC alloys , *ALLOY powders , *MECHANICAL alloying , *HYPEREUTECTIC alloys , *STAINLESS steel , *CRYOGENIC grinding , *METAL powders , *IRON powder - Abstract
This study reports on the detailed microstructural characterization of Al-12.6 wt.% Si eutectic alloy powders synthesized from Al and Si elemental starting materials via mechanical alloying (MA) for 4, 6, and 8 h, and subsequent cryomilling (CM). Mechanically alloyed (MA'd) powders were cryomilled (CM'd) for 10, 20, and 30 min in a freezer/mill using liquid N2 gas circulated externally around the polycarbonate milling vial containing stainless steel rods. SEM/EDS and TEM/EDS mapping analyses revealed the presence of some Si embedded in the Al-rich particles and some existed as free Si. As expected, with increasing MA and sequential milling (MA + CM) duration, strain values increased and crystallite sizes decreased. Si solubility in α-Al was enhanced with increasing MA durations and utilizing MA and CM consecutively (sequential milling) as indicated by DSC endothermic and XRD peak shifts. A maximum solubility of 2.25 at.% Si in α-Al or Si solid solubility extension of 0.65 at.% was estimated for the Al12.6Si eutectic alloy powders MA'd for 8 h. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
- Full Text
- View/download PDF
45. Solid-state compounding of immiscible PCL-PEO blend powders for molding processes.
- Author
-
Allaf, Rula M., Albarahmieh, Esra'a, and AlHamarneh, Baider M.
- Subjects
MANUFACTURING processes ,POLYMERIC composites ,DIFFERENTIAL scanning calorimetry ,COMMODITY futures ,POWDERS ,MIXING ,POLYCAPROLACTONE ,IRON powder - Abstract
Solid-state milling is a promising ecologically friendly method for fabricating polymeric blend and composite powder raw materials for several subsequent manufacturing processes. Biodegradable polymers, blends, and composites are expected to find extensive use by industry due to their environmental friendliness and acceptable mechanical and thermal properties for several applications. Poly-ε-caprolactone (PCL), poly-ethylene-oxide (PEO), and their blends have attracted so much attention to replace commodity polymers in future applications. Therefore, in the current research, bulk compounding of PCL-PEO blends with various compositions using solid-state cryomilling was investigated. Structural, mechanical, thermal, and hydrophilicity properties were examined on samples obtained by compression molding to explore the capabilities of the milling process for various applications. Morphology of the blends was explored by scanning electron microscopy (SEM), which showed a clear phase separation in blends after heating. Dispersed as well as co-continuous morphologies were achieved by varying composition. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) of the blends indicated insignificant amorphization by milling. Tensile strength, modulus, and percentage elongation at break of the blends demonstrated significant variations due to processing parameters. Image 1 • Cryomilling is a green, cheap, simple and effective route to produce blend powders. • Cryomilling provides adequate compounding despite immiscibility of components. • PCL/PEO blend powders with different compositions were fabricated via cryomilling. • Blend mechanical properties were modulated through varying blend composition. • Blend morphologies were modified through manipulating processing parameters. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
- Full Text
- View/download PDF
46. Recycling of additively printed rare-earth bonded magnets.
- Author
-
Gandha, Kinjal, Ouyang, Gaoyuan, Gupta, Shalabh, Kunc, Vlastimil, Parans Paranthaman, M., and Nlebedim, Ikenna C.
- Subjects
- *
REMANENCE , *MAGNETS , *RARE earth metals , *MAGNETIC properties , *CRYOGENIC grinding , *PLASTIC scrap recycling - Abstract
• New bonded magnets made with wastes from additive manufacturing (AM). • Environmentally benign process for recycling waste AM polymer bonded NdFeB magnets. • Process is simple and can be easily integrated into existing or new startup plants. • Process enables closed-loop sustainability in critical rare earth elements supply. • Properties of recycled magnets are on par with original end-of-life materials. In this work, we describe an efficient and environmentally benign method of recycling of additive printed Nd-Fe-B polymer bonded magnets. Rapid pulverization of bonded magnets into composite powder containing Nd-Fe-B particles and polymer binder was achieved by milling at cryogenic temperatures. The recycled bonded magnets fabricated by warm compaction of ground cryomilled coarse composite powders and nylon particles showed improved magnetic properties and density. Remanent magnetization and saturation magnetization increased by 4% and 6.5% respectively, due to enhanced density while coercivity and energy product were retained from the original additive printed bonded magnets. This study presents a facile method that enables the direct reuse of end-of-life bonded magnets for remaking new bonded magnets. In addition to magnetic properties, mechanical properties comparable to commercial products have been achieved. This research advances efforts to ensure sustainability in critical materials by forming close loop supply chain. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
- Full Text
- View/download PDF
47. Phase-pure τ-MnAlC produced by mechanical alloying and a one-step annealing route.
- Author
-
Øygarden, Vegar, Rial, Javier, Bollero, Alberto, and Deledda, Stefano
- Subjects
- *
PHASE transitions , *MANGANESE , *MECHANICAL properties of metals , *ANNEALING of metals , *METAL quenching - Abstract
Abstract Phase-pure τ -MnAlC powder has been synthesized using mechanical alloying followed by a single annealing step. Mechanical alloying from the elemental constituents resulted in 100 wt.% nanocrystalline β -Mn(Al) phase. Complete β -Mn(Al) to τ -MnAlC phase transformation – via the high-temperature ε -phase – was obtained through annealing and quenching of the as-milled powder. The influence of the quenching rate (3.5–100 °C/s) is discussed in detail. Powder synchrotron X-ray and neutron diffraction data was used to confirm phase-purity, and to determine the magnetic moments of Mn. A coercivity of 0.15 T was obtained for the as-synthesized τ -MnAlC, significantly higher than previously reported values for τ -MnAlC synthesized with a one-step route. A systematic study utilizing cryomilling was attempted to further increase the coercivity. Highlights • τ -MnAlC was synthesized using mechanical alloying followed by a single annealing step • A cooling rate of about 3.5 °C/min was used to form high-purity τ-phase • The observed coercivity is significantly higher than previous reports for τ -MnAlC produced with a one-step route. • Coercivity increased after cryomilling for very short times up to 7 min, but the loss of magnetization was significant. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
- Full Text
- View/download PDF
48. Insights into emerging organic pollutants extraction from polypropylene, polystyrene, and polyethylene microplastics.
- Author
-
Jiménez-Skrzypek, Gabriel, Lusiardi, Rachele, González-Sálamo, Javier, Vega-Moreno, Daura, and Hernández-Borges, Javier
- Subjects
- *
PLASTIC marine debris , *EMERGING contaminants , *MICROPLASTICS , *POLYPROPYLENE , *HIGH density polyethylene , *POLYETHYLENE , *BIODEGRADABLE plastics - Abstract
Microplastics have the capability of retaining contaminants on their surface, increasing their persistence, preconcentrating them, and acting as transport vectors. Nevertheless, the determination of these compounds in plastic matrices poses several analytical issues and challenges, including the capability of many of these methods of only determining the extractable pollutants fractions, repeatability issues, etc. In this sense, it is primordial to evaluate the effect of the critical parameters that allow to obtain a quantitative extraction of the target analytes from microplastics, including the matrix effect of each of the studied polymers, the influence of particle size, and the effect of weathering. A simple and effective methodology for the extraction of 17 emerging organic pollutants from both pristine (polypropylene, polystyrene, and low- and high-density polyethylene) and weathered (polypropylene and polyethylene) microplastics has been developed, optimized, and validated, achieving recovery values of 70–120 % and low method quantification limits (9.2–35.5 ng/g). Results show the importance of cryomilling microplastics (as smaller particle sizes improve recovery and homogenization), something ignored in most publications. The differences in matrix effect for the studied pristine polymers highlights the importance of treating polymers individually, without extrapolating results. In weathered microplastics, matrix effect is overall higher than in their pristine counterparts, evidencing the necessity of always carrying out matrix effect and recovery studies in environmental microplastics. The analysis of 10 samples collected in Playa Grande (Tenerife, Canary Islands, Spain) revealed quantitative amounts of bisphenol A (10.8 ± 3.4 ng/g) in one of them. For the first time, the effect of particle size, weathering and matrix effect have been simultaneously evaluated on microplastics, revealing the importance of their assessment to properly validate the methodology. Additionally, the method shows good performance in all the different polymers and has been successfully applied to the analysis of environmental samples of microplastics. • Contaminants extraction from microplastics involve important challenges. • Microplastics size, weathering and polymeric matrix effect should be studied. • Microplastics cryomilling allows a suitable homogenization and replicate analysis. • Smaller particle sizes highly improve the recoveries values obtained. • Weathered microplastics show higher matrix effect than pristine ones. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
49. Thermal Stability and Microstructure of Nanometric 2024 Aluminum Alloy Powder Obtained by Cryogenic Milling and Spark Plasma Sintering
- Author
-
Kétner Bendo Demétrio and Alberto Molinari
- Subjects
2024 Al alloy ,cryomilling ,SPS ,thermal stability ,characterization ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Metals and nanocrystalline alloy powders can be produced by high-energy milling and be consolidated by sintering techniques; the use of relatively low sintering temperatures maintains nanometric grains by avoiding grain growth. In the present study, 2024 aluminum alloy powders were produced by milling at cryogenic temperatures (cryomilling) and consolidation using spark plasma sintering (SPS). The thermal stability and microstructure of the nanometric 2024 Al alloy powder produced by cryomilling were analyzed. The milled powder was degassed to improve its sintering behavior and avoid the presence of pores in the final sintered piece. When the material was consolidated by SPS at a temperature of 525 ºC and under a pressure of 60 MPa, the resulting alloy density was 98% and an ultra-fine grained (100-300 nm)/micrometric microstructure. The hardness and microhardness of the milled degassed sintered samples showed values superior to atomized samples. The material also presented nanopores in the grain boundaries, very fine precipitates of AIN, rounded θ phases (Al2Cu), and elongated S phases (Al2CuMg). more...
- Published
- 2018
- Full Text
- View/download PDF
50. Studies on the Vitrified and Cryomilled Bosentan
- Author
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Kinga Hyla, K. Koperwas, Krzysztof Chmiel, Rafał Łunio, Karolina Jurkiewicz, Daniel Żakowiecki, Marian Paluch, Aldona Minecka, Ewa Kamińska, Bartłomiej Milanowski, Barbara Hachuła, and Kamil Kaminski
- Subjects
Materials science ,Analytical chemistry ,Pharmaceutical Science ,Dielectric ,Article ,Differential scanning calorimetry ,X-Ray Diffraction ,Spectroscopy, Fourier Transform Infrared ,Drug Discovery ,cryomilling ,Fourier transform infrared spectroscopy ,dissolution rate ,Supercooling ,Dissolution ,molecular mobility ,Calorimetry, Differential Scanning ,bosentan ,vitrification ,Amorphous solid ,Dielectric spectroscopy ,Thermogravimetry ,Drug Liberation ,Dielectric Spectroscopy ,Molecular Medicine ,water removal - Abstract
In this paper, several experimental techniques [X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetry, Fourier transform infrared spectroscopy, and broad-band dielectric spectroscopy] have been applied to characterize the structural and thermal properties, H-bonding pattern, and molecular dynamics of amorphous bosentan (BOS) obtained by vitrification and cryomilling of the monohydrate crystalline form of this drug. Samples prepared by these two methods were found to be similar with regard to their internal structure, H-bonding scheme, and structural (α) dynamics in the supercooled liquid state. However, based on the analysis of α-relaxation times (dielectric measurements) predicted for temperatures below the glass-transition temperature (Tg), as well as DSC thermograms, it was concluded that the cryoground sample is more aged (and probably more physically stable) compared to the vitrified one. Interestingly, such differences in physical properties turned out to be reflected in the lower intrinsic dissolution rate of BOS obtained by cryomilling (in the first 15 min of dissolution test) in comparison to the vitrified drug. Furthermore, we showed that cryogrinding of the crystalline BOS monohydrate leads to the formation of a nearly anhydrous amorphous sample. This finding, different from that reported by Megarry et al. [Carbohydr. Res.2011, 346, 1061−106421492830] for trehalose (TRE), was revealed on the basis of infrared and thermal measurements. Finally, two various hypotheses explaining water removal upon cryomilling have been discussed in the manuscript. more...
- Published
- 2021
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