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While post‐synthesis processing steps are frequently applied in the preparation of cathode composites for solid‐state batteries to ensure homogeneous mixing and good contact with the cathode active material, little is known about the processes that occur during milling and how they influence structure and transport of solid electrolytes. Here, an extensive set of experimental methods and simulations are used to study the effects of post‐synthesis milling by a frequency and planetary ball mill on the highly conducting chloride‐rich argyrodite Li5.5PS4.5Cl1.5. Structural analyses show that processing can reduce the coherence length and increase the disorder. The reduced crystallite size correlates with a decrease in ionic conductivity in the post‐processed solid electrolytes. Simulating the ball milling processes by the discrete element method provides fundamental understanding and reveals the correlation of the loss in coherence with the specific energy input and the numbers of stressing events during the milling process. An observed decrease in particle size in ball milled samples leads to lower tortuosity in the cathode composites. As the loss in coherence and decrease in particle size have opposite effects on the performance, optimizing these processing conditions will play a significant role on the road to highly performing solid‐state batteries. [ABSTRACT FROM AUTHOR]

Fe50Mn35Sn15 Heusler alloy, obtained by mechanical alloying, was subjected to larger milling times in the range of 30–50 h to study the phase stability and morphology. X-ray diffraction studies have shown that the milled samples crystallise in a disordered A2 structure. The A2 structure was found to be stable in the milling range studied, contrary to the computation studies performed on this composition. Using Rietveld refinements, the lattice parameter, mean crystallite size, and lattice strain were computed. The nature of the obtained phases by milling was found to be nanocrystalline with values below 50 nm. A linear increase rate of 0.00713 (h−1) was computed for lattice strain as the milling time increased. As the milling time increases, the lattice parameter of the cubic Heusler was found to have a decreasing behaviour, reaching 2.9517 Å at 50 h of milling. The morphological and elemental distribution—characterised by scanning electron microscopy and energy-dispersive X-ray spectroscopy—evidenced Mn and Sn phase clustering. As the milling time increased, the morphology of the sample was found to change. The Mn and Sn cluster size was quantified by elemental line profile. Electrical resistivity evolution with milling time was analysed, showing a peak for 40 h of milling time. [ABSTRACT FROM AUTHOR]

H 2 generation through hydrolysis of Al-composites has received eclectic attention for on-demand H 2 applications such as low-power proton exchange membrane fuel cells. In this line, we prepared Multi-Walled Carbon Nanotubes (MWCNT)/Al–Bi–NaCl nanocomposites and tested them for enhanced H 2 generation. These nanocomposites are prepared using high-energy ball milling followed by uni-axial cold compaction. H 2 generation by these nanocomposites was tested using tap water at room temperature. An excellent maximum H 2 generation rate of 13.33 mLg−1s−1 with an H 2 yield of 98% and an induction time of less than 10 s is achieved. Analysis of different observations shows that adding an optimum percentage of MWCNT to the Al–Bi–NaCl composite results in flaky morphology, which facilitates easily accessible water pathways, enhancing the H 2 generation rate of the nanocomposites. Also, an enhanced number of MWCNT/Al–Bi microgalvanic cells, optimum utilization of electrical conductivity of MWCNT, and dissolution of NaCl favored the H 2 generation. [Display omitted] • MWCNT/Al–5Bi–5NaCl nanocomposites are prepared by milling and cold compaction. • H 2 yield of 98% and an induction time of <10 s is achieved. • Maximum H 2 generation rate of 13.33 mLg−1s−1 is achieved. • The synergistic effect of MWCNT and NaCl enhanced H 2 generation. • An optimum quantity of MWCNT is required for the best results. [ABSTRACT FROM AUTHOR]

Metallic substances are favored for storing and transporting spent nuclear fuels (SNFs) due to their thermal stability, mechanical strength, and corrosion resistance. Adding gadolinium (Gd) significantly enhances neutron shielding, improving efficiency with reduced thickness and dimensions. In this study, Al–Gd 2 O 3 metal nanocomposites were synthesized using powder-processed mechanical milling. The crystal structure features of (100-x)Al-x%Gd 2 O 3 samples with varying percentages of Gd 2 O 3 (5 %, 10 %, and 15 % by weight) were analyzed by X-ray diffraction. Microstructural properties were studied using scanning and transmission electron microscopy (SEM and TEM). The synthesized composites' neutron and γ-radiation shielding characteristics were investigated theoretically using the MCNP6.2 transport code. Analysis of the XRD data revealed prominent peak shifts with increased milling time, indicating reduced particle sizes. Differential scanning calorimetry (DSC) indicated Gd 2 O 3 -induced changes in temperature behavior, and the Vickers microhardness tests demonstrated enhanced mechanical strength with increasing gadolinium concentration. Improved neutron radiation shielding was observed with higher Gd 2 O 3 content. Our study highlights the potential of Gd 2 O 3 -enriched metal matrix composites for advanced industrial applications. [ABSTRACT FROM AUTHOR]

This study investigates the impact of Sm3+ substitution on the structural, electrical, magnetic, and electrochemical properties of CoFe 2 O 4 nanoparticles prepared via a combined solid-state reaction and mechanical milling approach. Rietveld refinement analysis confirms the presence of single-phase cubic spinel structures within the Fd3m space group for both CoFe 2 O 4 (CF) and Co 0.95 Sm 0.05 Fe 2 O 4 (SmCF). Field emission scanning electron microscopy and energy dispersive spectroscopy are employed to validate the microstructure and elemental composition. Tauc plot analysis reveals a decrease in the band gap from 2.24 eV for CF to 2.07 eV for SmCF. Hysteresis loop measurements demonstrate an enhancement in saturation magnetization, remanent magnetization, and magnetic moment for SmCF, indicating improved magnetic properties. Furthermore, a substantial increase in magneto-crystalline anisotropy is observed with Sm³⁺ doping. Frequency-dependent dielectric properties are investigated using Havriliak–Negami fitting, confirming the presence of Cole-Cole dispersion. A direct correlation between the dielectric constant and temperature is identified, suggesting higher temperatures lead to elevated values. Notably, the incorporation of Sm³⁺ results in a significant enhancement in specific capacitance, positioning SmCF as a promising candidate for energy storage applications, particularly in supercapacitors. [ABSTRACT FROM AUTHOR]

This study investigates the sintering mechanism of commercially pure Magnesium (Mg) using the Field Assisted Sintering Technique (FAST). Powder morphologies are in a vast variety of spherical to flake, as well as nano to fine grain as in powder size and mechanically milled (MM) between 0-108 hours. The MM'ed Mg particles were sintered by FAST with at 350-425°C for 5-20min. Relative densities (93-99%) and compressive strength up to 369MPa were obtained from FAST'ed Mg samples depending on MM durations and particle geometries which significantly influenced the sintering mechanism. SEM and XRD analysis identified four distinct bonding and sintering mechanisms influenced by particle geometry, residual stress, and microstructure developed through mechanical milling. The combination of mechanical milling and FAST exhibited significant effects on the microstructural and mechanical properties of Mg powders, with the Mg36 sample displaying promising strength and hardness. [ABSTRACT FROM AUTHOR]

Ultrafine copper powders were prepared by the air-jet milling of copper oxide (CuO) powders and a subsequent hydrogen (H2) reduction. After milling, the particle size and grain size of CuO powders decreased, while the specific surface area and structural microstrain increased, thereby improving the reaction activity. In a pure H2 atmosphere, the process of CuO reduction was conducted in one step, and followed a pseudo-first-order kinetics model. The smaller CuO powders after milling exhibited higher reduction rates and lower activation energies compared with those without milling. Based on the unreacted shrinking core model, the reduction of CuO powders via H2 was controlled by the interface reaction at the early stage, whereas the latter was limited by the diffusion of H2 through the solid product layer. Additionally, the scanning electron microscopy (SEM) indicated that copper powders after H2 reduction presented a spherical-like shape, and the sintering and agglomeration between particles occurred after 300 °C, which led to a moderate increase in particle size. The preparing parameters (at 400 °C for 180 min) were preferred to obtain ultrafine copper powders with an average particle size in the range of 5.43–6.72 μm and an oxygen content of less than 0.2 wt.%. [ABSTRACT FROM AUTHOR]

Hot pressing represents a promising consolidation technique for ball-milled bismuth telluride alloys, yet deep investigations are needed to understand its effect on the thermoelectric properties. This paper studies the effect of hot-pressing parameters (temperature and pressure) on the thermoelectric properties of the n-type Gr-Bi2Te2.55Se0.45 nanocomposite. Ultra-high pressure, up to 1.5 GPa, is considered for the first time for consolidating Bi2(Te,Se)3 alloys. Results from this study show that increasing the temperature leads to changes in chemical composition and causes noticeable grain growth. On the contrary, increasing pressure mainly causes improvements in densification. Overall, increments in these two parameters improve the ZT values, with the temperature parameter having a higher influence. The highest ZT of 0.69 at 160 °C was obtained for the sample hot-pressed at 350 °C and 1 GPa for 5 min, which is indeed an excellent and competitive value when compared with results reported for this n-type Bi2Te2.55Se0.45 composition. [ABSTRACT FROM AUTHOR]

This study focuses on the fabrication and analysis of aluminum nickel phosphorus bronze (AlNPB) metal matrix composite (MMC), reinforced with synthesized TiCN + SiC nanopowders, for potential ballistic applications. The nanopowders were synthesized via mechanical milling and characterized through PXRD, FTIR, and FESEM analyses. The crystalline size from XRD data averaged 24.8 nm, while the FTIR analysis identified axiometic modes and functional groups of the nanocomposite. SEM images displayed the irregular morphologies of the composite powders. The AlNPB MMC was fabricated by incorporating 2%, 4%, and 6 wt. % of the TiCN + SiC nanocomposite with the bronze alloy, utilizing a stir casting technique. XRD and FESEM results confirmed the formation of the MMC and illustrated the composite's porous morphology. Mechanical performance, including tensile, compression, and hardness tests, showed optimal properties with 4 wt. % reinforcement, yielding a tensile strength of 753 MPa, a hardness of 448 HBW, and compression strength of 77.9 J, coupled with good corrosion resistance. Furthermore, a ballistic analysis of the MMC demonstrated a reduction in residual strain energy after bullet impact on a 4 wt% reinforcement target plate compared to the 2% and 6% TiCN + SiC nanoparticle-reinforced aluminum bronze matrix composites. This study therefore suggests that an AlNPB MMC with 4 wt% reinforcement offers the most promising balance of mechanical properties for ballistic applications. [ABSTRACT FROM AUTHOR]

The powder metallurgy (PM) route for the production of closed-cell metallic foams has recently received a significant amount of attention. One of the major issues is the non-uniform and non-spherical nature of the cells produced, which can negatively affect the mechanical behavior. The current paper uses the PM route to process metallic foams for the first time using novel Al-TiH2 foamable precursor "particles" (FPPs). The effect of FPP content (0–10 wt.%) on the developed foam structure of aluminum and its mechanical properties is investigated. An increase in FPP content results in a decline in product density by forming uniform and near-spherical cells. The main advantage of the FPPs is the localization of the blowing agent TiH2 particle content within Al-TiH2 composite particles (i.e., giving rise to a higher local TiH2 content), which has led to the production of pores with relatively high circularities even at very low overall TiH2 contents. The foams produced displayed energy absorption capacities of 10–25 MJ/m3 at 50% strain, and maximum energy absorption efficiencies ranging from 0.6–0.7 (for 40–60% closed cell content) [ABSTRACT FROM AUTHOR]

Improving the ductile deformation behavior of Mg-SiC nanocomposites without compromising strength is critical to enhancing their mechanical properties. Mg-SiC nanocomposites are produced through mechanical milling, cold isostatic pressing, sintering, and hot extrusion processes. This study investigates the uniaxial stress–strain response and deformation behavior of the Mg-SiC nanocomposite compared to pure Mg samples with and without the milling process. The deformation behavior was investigated by two-dimensional (2D) digital image correlation (DIC) at two macroscopic and microscopic scales, employing light micrographs and in situ loading samples, respectively, in the scanning electron microscope. Compared to the pure Mg samples, the mechanical test results demonstrated a significant improvement in strength (80 MPa) and fracture strain (23.5%) of the Mg-SiC nanocomposite. The three-dimensional (3D) representative volume element (RVE) model revealed the particle dispersion effect on the mechanical properties of the nanocomposite. The RVE results demonstrate ductile deformation behavior in the sample with homogenous dispersion of SiC particles compared with the heterogeneous dispersion of SiC particles in Mg-SiC nanocomposite. The results demonstrated a good agreement between DIC and RVE predictions for Mg-SiC nanocomposites across macro- and microscales. [ABSTRACT FROM AUTHOR]

A unique deformation microstructure introduced by 20% cold rolling in a Ti-25mass%Nb-25mass%Zr (TNZ) Harmonic Structure (HS) alloy has been studied in detail by crystallographic analysis. The HS consists of soft, coarse-grained regions (Core) that are three-dimensionally surrounded by an interconnected network of hard, ultrafine-grained regions (Shell). The {332}<113> deformation twins are observed in the deformation microstructure of the homogeneous grained TNZ alloy compacts with a sinter holding time of 1.8 ks. In contrast, in the deformation microstructure of the TNZ alloy HS compacts with a sintering holding time of 1.8 ks, deformation bands by slip deformation are observed in Core region. In the deformation microstructure of the TNZ alloy HS compact with a sintering holding time of 0 s, a composite deformation microstructure consisting of two types of deformation bands, {332}<113> deformation twins and <110> axial rotation slip bands, is observed in Core region. It is noteworthy that the same HS material has different deformation structures depending on the sintering time. The reason for the formation of different deformation structures is the effect of the diffusion of Fe elements doped by mechanical milling [ABSTRACT FROM AUTHOR]

The utilization of porous biomedical implants featuring a bimodal microstructure has garnered substantial interest within the scientific community. This study delves into the intricate interplay between processing parameters, microstructural attributes, and the tribo-mechanical performance of titanium grade 4, showcasing its potential to serve as implants to address compromised cortical bone tissue. The investigation meticulously examines the impact of milling duration (10 and 20 h), proportion of milled powder (50 and 75 wt%), and the volume fraction of space-holding agents (40–60 vol% NaCl) on the resulting characteristics of the bimodal microstructure, which plays a crucial role in achieving optimal biomechanical equilibrium. The Vickers microhardness, conventional and instrumented (P-h curves), and the wear behavior (ball-on disk) are discussed in terms of bimodal microstructure distribution, particle size and porosity level inherent to the fabrication conditions (mechanical milling + space-holder + hot-pressing). In general terms, milling time and milled powder fraction were the most influent parameters on the final properties of the materials. With the processing route used, the achieved microhardness values and wear behavior are comparable with those obtained by means of surface modifications or alloys. The Young's moduli obtained were in the range of 30–50 GPa, which could help to reduce the shielding phenomenon, while presenting a good mechanical resistance and wear behavior. In light of these findings, the fabricated specimen, composed of 75 wt% milled powder subjected to a 10-h milling duration, supplemented by a 60 vol% fraction of NaCl, emerges as a prime candidate manifesting superior biomechanical equilibrium. This judicious configuration exhibits a promising trajectory for its application in bone replacement endeavors.

In this study, we compare the thermoelectric properties of coarse-grained n-type Bi2Te2.55Se0.45 alloy prepared by induction melting with the bulk-nanostructured prepared by ball milling and hot-pressing techniques. The corresponding thermoelectric properties showed different behavior for each material processed using different routes. The most striking result of the study is observing a p-type behavior and charge carrier transition from p-to n-type for the coarse-grained alloy. These observed phenomena are related mainly to the unique needle-like microstructure accompanied by high lattice strain. Lastly, the obtained figure-of-merit values for the coarse needle-like structure and bulk nanostructured Bi2Te2.55Se0.45 alloys are 0.20 and 0.80 at their optimum temperatures of 60 and 120 °C, respectively.

Fe50Mn35Sn15 Heusler alloy, obtained by mechanical alloying, was subjected to larger milling times in the range of 30–50 h to study the phase stability and morphology. X-ray diffraction studies have shown that the milled samples crystallise in a disordered A2 structure. The A2 structure was found to be stable in the milling range studied, contrary to the computation studies performed on this composition. Using Rietveld refinements, the lattice parameter, mean crystallite size, and lattice strain were computed. The nature of the obtained phases by milling was found to be nanocrystalline with values below 50 nm. A linear increase rate of 0.00713 (h−1) was computed for lattice strain as the milling time increased. As the milling time increases, the lattice parameter of the cubic Heusler was found to have a decreasing behaviour, reaching 2.9517 Å at 50 h of milling. The morphological and elemental distribution—characterised by scanning electron microscopy and energy-dispersive X-ray spectroscopy—evidenced Mn and Sn phase clustering. As the milling time increased, the morphology of the sample was found to change. The Mn and Sn cluster size was quantified by elemental line profile. Electrical resistivity evolution with milling time was analysed, showing a peak for 40 h of milling time.

Magnesium has been regarded as an intriguing anode material for chloride ion batteries (CIB) because of its abundant resources, multi-electron reaction feature, and high volumetric capacity. However, the passivation of magnesium in the electrolyte and formation of insulating MgCl2 discharge product lead to poor reaction activity of magnesium anode in CIBs. Herein, the Mg2Sn alloy prepared by mechanical alloying of magnesium and tin powders is first developed as the anode material with enhanced interfacial activity in the CIB using a metal chloride cathode. The cathode exhibits a significant increase in the discharge capacity from 82 to 175 mAh g−1 when an Mg/carbon anode was replaced by the Mg2Sn alloy anode. The discharge capacity can be further increased to more than 200 mAh g−1 when the graphene nanoplatelet is incorporated in the Mg2Sn alloy by mechanical milling, thus demonstrating the highly active alloy anode for chloride ion storage. This strategy also benefits the improvement in the cycling performance of the magnesium anode. [ABSTRACT FROM AUTHOR]

Copper matrix composites with zirconium diboride (ZrB2) were synthesised by ball milling and consolidated by Spark Plasma Sintering (SPS). Characterisations of the ball-milled composite powders were performed by scanning electron microscopy (SEM), X-ray diffraction, and measurement of the particle size distribution. The effect of the sintering temperature (1123 K, 1173 K, and 1223 K) and pressure (20 MPa and 35 MPa) on the density, porosity, and Young's modulus was investigated. The relationship between the change of Orb content and physical, mechanical, and electrical properties was studied. Experimental data showed that the properties of Cu–Orb composites depended significantly on the SPS sintering conditions. The optimal sintering temperature was 1223 K with a pressure of 35 MPa. Composites exhibited a high degree of consolidation. For these materials, the apparent density was in the range of 93–97%. The results showed that the higher content of Orb in the copper matrix was responsible for the improvement in Young's modulus and hardness with the reduction of the conductivity of sintered composites. The results showed that Young's modulus and the hardness of the Cu 20% Orb composites were the highest, and were 165 GPa and 174 HV0.3, respectively. These composites had the lowest relative electrical conductivity of 17%. [ABSTRACT FROM AUTHOR]

Mineral trioxide aggregates (MTA) are commonly used as endodontic filling materials but suffer from a long setting time and tooth discoloration. In the present study, the feasibility of using barium titanate (BTO) for discoloration and a calcium chloride (CaCl2) solution to shorten the setting time was investigated. BTO powder was prepared using high-energy ball milling for 3 h, followed by sintering at 700–1300 °C for 2 h. X-ray diffraction was used to examine the crystallinity and crystalline size of the as-milled and heat-treated powders. MTA-like cements were then prepared using 20–40 wt.% BTO as a radiopacifier and solidified using a 0–30% CaCl2 solution. The corresponding radiopacity, diametral tensile strength (DTS), initial and final setting times, and discoloration performance were examined. The experimental results showed that for the BTO powder prepared using a combination of mechanical milling and heat treatment, the crystallinity and crystalline size increased with the increasing sintering temperature. The BTO sintered at 1300 °C (i.e., BTO-13) exhibited the best radiopacity and DTS. The MTA-like cement supplemented with 30% BTO-13 and solidified with a 10% CaCl2 solution exhibited a radiopacity of 3.68 ± 0.24 mmAl and a DTS of 2.54 ± 0.28 MPa, respectively. In the accelerated discoloration examination using UV irradiation, the color difference was less than 1.6 and significantly lower than the clinically perceptible level (3.7). This novel MTA exhibiting a superior color stability, shortened setting time, and excellent biocompatibility has potential for use in endodontic applications. [ABSTRACT FROM AUTHOR]

For practical applications of zinc oxide (ZnO) nanoparticles (NPs) in the field of optoelectronics, a control over particle size with proper understanding of defects in the NPs has become crucial nowadays. In the present study, an effort has been given to both controlling the size and understanding the evolution of defects in ZnO NPs synthesized using mechanical (ball) milling. Ball milling of ZnO nanopowder (of average size ~ 46.8 nm) in air ambient was found to reduce the size of NPs very fast reaching a value as small as ~ 16.3 nm for a ball milling time of 10 h. A size saturation of the NPs was seen beyond the time of milling of 10 hours. X-ray diffraction and optical absorption spectroscopy studies confirmed that the stress and the band gap of the NPs were found to increase with decrease in particle size due to increased surface to volume ratio of the NPs and the quantum confinement effects, respectively. Raman and photoluminescence spectroscopy studies revealed the increase in zinc interstitials (Zni) and decrease in oxygen vacancies (Vo) with increase in size of ZnO NPs. A correlation between NP size and the defects (Vo and Zni) in it is established. These correlations can be utilized for relative quantification of the defects in ZnO NP of a particular size. It is concluded that the defects in the small ZnO NPs are inherently induced because of the reduced size but not due to ball milling. So it is very unlikely to synthesize defect-free ZnO NPs. [ABSTRACT FROM AUTHOR]

The purpose of this research is to produce high hardness of Mg from cutting chips using MM-SPS process. Effects of different starting materials, such as powder and cutting chips of Mg, on the properties were investigated. The influence of sintering holding times on the properties was also investigated to establish between the process conditions and the properties. Hardness testing and X-ray diffraction were carried out for characterization of powders and bulk materials. The results of hardness indicated that MM-SPS process can synthesis upgrade recycled material fabricated from Mg cutting chips. In the case of cutting chips, the maximum hardness was observed at 6 hours of MM and 60 min of sintering holding time. On the other hand, in the case of powder showed the maximum hardness at 6 hours of MM and 10 min of sintering holding time. However, the hardness did not increase with increasing sintering holding time. No solid-state reaction was observed in SPS materials fabricated from powder and cutting chips. In addition, no contamination of impurities during MM treatment was observed. [ABSTRACT FROM AUTHOR]

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Ultrafine copper powders were prepared by the air-jet milling of copper oxide (CuO) powders and a subsequent hydrogen (H2) reduction. After milling, the particle size and grain size of CuO powders decreased, while the specific surface area and structural microstrain increased, thereby improving the reaction activity. In a pure H2 atmosphere, the process of CuO reduction was conducted in one step, and followed a pseudo-first-order kinetics model. The smaller CuO powders after milling exhibited higher reduction rates and lower activation energies compared with those without milling. Based on the unreacted shrinking core model, the reduction of CuO powders via H2 was controlled by the interface reaction at the early stage, whereas the latter was limited by the diffusion of H2 through the solid product layer. Additionally, the scanning electron microscopy (SEM) indicated that copper powders after H2 reduction presented a spherical-like shape, and the sintering and agglomeration between particles occurred after 300 °C, which led to a moderate increase in particle size. The preparing parameters (at 400 °C for 180 min) were preferred to obtain ultrafine copper powders with an average particle size in the range of 5.43–6.72 μm and an oxygen content of less than 0.2 wt.%.

AbstractIntroduction: : The purpose of this research is solid state recycling of 3000 and 5000 series aluminum alloy scrap to produce aluminum nano-crystalline powder by mechanical milling without using process controlling agent. In this regard, aluminum used beverage cans (UBCs) which consist of lid (alloy 5182) and the monolith part (alloy 3004) of the body (thin) and bottom (thicker).Methods: To achieve disintegration mechanism, lid part, body and bottom of monolith part are separated each other because of diverse constituent of Al series and different thickness. The three parts individually were decoated then cut into the small chips (app. 8 mm). The chips were mechanically ball milled at different times up to 104 hours under argon atmosphere. The ratio of ball to powder was 10 to 1. Findings: The lid part chips are crushed faster than the monolith part chips, and, resulting in a finer powder. According to the PSA results, the D90 of the lid powder is less than 150 micrometers; while D90 of the body and bottom powders are more than 150 micrometers. This result can be used on an industrial scale to separate the constituent elements of crushed UBCs from each other. The smallest D90 values of lid, body and bottom powders, which obtained after 72, 80 and 80 h as optimum milling time, are 109, 258 and 391, respectively. Also, their flowability were 57.8, 59.3 and 61.1 s/50 g, as well as the apparent density were 1.38, 1.43 and 1.46 g/cm3, respectively.

The present research examines the development of new porous ceramic bricks from Hungarian zeolitic tuff and tea waste as building materials. Recycling waste materials as a pore-forming agent in brick-making is a promising solution to environmental and economic challenges. Several zeolitic tuff/tea waste admixtures were milled in the planetary ball milling to produce homogenous powders. The substitution ratios were maintained as 0 %, 2 %, 4 %, 6 %, 8 %, 10 %, and 12 % by wt of zeolitic tuff. The ceramic disks were produced from the prepared mixtures via dry pressing and sintering at various temperatures (950–1250 °C) for consolidation. The produced bricks were investigated based on bulk density, apparent porosity, water absorption, volume shrinkage, thermal conductivity and compressive strength, as well as mineralogical, chemical, and morphological studies. The mineralogical determination confirms the existence of clinoptilolite, montmorillonite, cristobalite and illite as major phases in zeolite tuff. The experimental results reveal that the addition of tea waste produces hybrid bricks with better thermal insulation (0.17–0.504 W/m K), lighter weight (1.37–1.81 g/cm3), and lower compressive strength (5.52–34.4 MPa). However, the compressive strength value still lies within the range required by the standards. The production of burned bricks containing up to 10 wt% tea waste is viable without causing major changes in their technical characteristics. Developing new porous bricks using waste materials can help expand the application of sustainable and cost-effective insulation bricks in the construction industry.

In this study, the synthesis of tungsten carbides in a copper matrix by spark plasma sintering (SPS) is conducted and the microstructure formation mechanisms of the composite materials are investigated. The reaction mixtures were prepared by the high-energy mechanical milling (MM) of W, C and Cu powders. The influence of the MM time and SPS temperature on the tungsten carbide synthesis in an inert copper matrix was analyzed. It was demonstrated that the milling duration is a critical factor for creating the direct contacts between the W and C reactants and increasing the reactive transformation degree. A WC–W2C–Cu composite was fabricated from the W–C–3Cu powder mixture milled for 10 min and subjected to SPS at a temperature of 980 °C for 5 min. The formation of unconventional microstructures with Cu-rich regions is related to inter-particle melting during SPS. The WC–W2C–Cu composite showed a promising combination of mechanical and functional properties: a hardness of 300 HV, an electrical conductivity of 24% of the International Annealed Copper Standard, a residual porosity of less than 5%, a coefficient of friction in pair with a WC-6Co counterpart of 0.46, and a specific wear rate of the material of 0.52 × 10−5 mm3 N−1 m−1. [ABSTRACT FROM AUTHOR]

Amorphization via high energy ball milling is a solid state processing technique in which continuously moving balls transfer kinetic/impact energy to the powder particles. It leads to welding, fracturing, fragmentation and rewelding of the particles. During ball milling, non-equilibrium phases such as supersaturated solid solution, metastable phases, quasicrystalline phases and nanostructure alloy may form other than amorphous phase depending on energy imparted to the powder materials. It has been observed that the total energy imparted to the system plays more important role in phase transformation or amorphization than impact energy of individual balls. Mechanical alloying/milling is one of the most versatile techniques through which large amount of amorphous powders of a wide range of compositions can be synthesized. Experimental results indicated that instead of individual parameter, total energy should be taken into consideration during amorphization. The current authors have also observed that the total energy plays an important role in amorphization of Al86Ni8Y6 glassy system. [ABSTRACT FROM AUTHOR]

This research explores the impact of Cu composition, heating temperature, and milling time on the production of copper-tin alloy nanoparticles. By employing design of experiments techniques, the study systematically evaluates these input variables and their effects on particle size, optical density, and number of colonies. The identification of new Cu3Sn phases in the nanoparticle structure contributes to the novelty of this research. The findings highlight the potential for optimizing copper-tin alloy nanoparticle synthesis and enhancing their antibacterial properties. Mechanical alloying is found to produce nanoparticles up to 15 nm in size. Increasing the percentage of copper leads to improved antibacterial properties. This work provides insights into the synthesis process of copper-tin mechanical alloying and their potential for antibacterial applications. [ABSTRACT FROM AUTHOR]

The sample of Bi0.9Ca0.1Fe0.9Mn0.1O3 was prepared using mechanical milling technique, and further was successively given heat treatment. The structural analysis (XRD data) suggests that the sample crystallizes in the rhombohedral (R3c) crystal structure. The co-substitution of Ca–Mn in Bismuth Ferrite (BFO) improves surface properties and enhances the reduction in particle size. A dielectric study on the sample was inspected on varying temperature and frequency range. The impedance study reveals the sturdy dependence of electrical properties on both frequencies as well temperatures having corresponded with the morphology. Room temperature ferroelectric hysteresis (P-E) loop shows the presence of ferroelectricity and a small reduction in leakage current was detected. The magnetic measurement divulges the enrichment in magnetization because of the distortion in structure and partial destruction of spin cycloid originating from co-substitution. The extent of interaction between the dipoles present in the ceramics can be estimated by the calculation of M-E coupling coefficient. The existence of ferroelectricity, ferromagnetism, and magneto-electric effect in the sample supports the strong enhancement in the multiferroism and magneto-electric coupling of BFO. [ABSTRACT FROM AUTHOR]

The effect of mechanical milling on the thermal behavior of pyrophyllite ore from a deposit in Parsovići, Bosnia and Herzegovina, was characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Particle size distribution. The thermal behavior of the material was followed by thermogravimetric and differential thermal analysis and correlated to its microstructural properties. The Williamson-Hall model was used to calculate the crystallite size and microstrain. Mechanochemical treatment of pyrophyllite ore produced a substantial structural modification, mainly along the c axis, resulting in disorder and partial degradation of the crystal structure of the ore. The particle size diminution, induced defects, and microstrain in the crystal lattice cause decrease in the peak intensity until the final disappearance. As confirmed by scanning electron microscopy and particle-size-distribution analysis, the surface area and the agglomeration is more pronounced as grinding time increases. Dehydroxylation of the minerals in the unmilled ore was realized at 716oC confirm by FTIR analysis. The endothermic peak that corresponds to dehydroxylation is shifted toward lower temperatures and becomes broad giving rise to the formation of amorphous SiO2 as milling time increases.

Nanocrystalline (NC) magnesium alloys and composites present potential for improving energy efficiency in transportation applications due to outstanding strength. Unfortunately, softening owing to grain growth at elevated temperature would induce fatal invalidity. The NC SiCp/AZ91 composite was isothermally annealed. A study on the thermal stability, including phase transformation, grain growth, softening, and strengthening mechanisms was carried out. After annealing treatment at 673 K for 240 min, the average grain size of AZ91-15vol.%SiCp composite increased from 29.0 nm to 53.1 nm. Coherent interface between nano-scale Mg17Al12 precipitates and Mg matrix was certified by HRTEM. Pinning effect due to the dispersing submicron SiC particles with size of 164 nm and nano-scale Mg17Al12 precipitates and dragging effect due to dissolving Al element were the reasons for excellent thermal stability. After annealing treatment, the hardness values of AZ91-xvol.%SiCp (x = 5, 10 and 15) composites were 1.61 GPa, 1.48 GPa and 1.78 GPa. Taking annealed AZ91-15vol.%SiCp composite as an example, there was no evident softening phenomenon and the decreasing ratio was ∼2% in comparison with milled composite with hardness of 1.82 GPa. Non-thermal sensitive SiC particles and high thermal stability Mg matrix played a key role in non-softening of composites.

Hot pressing represents a promising consolidation technique for ball-milled bismuth telluride alloys, yet deep investigations are needed to understand its effect on the thermoelectric properties. This paper studies the effect of hot-pressing parameters (temperature and pressure) on the thermoelectric properties of the n-type Gr-Bi2Te2.55Se0.45 nanocomposite. Ultra-high pressure, up to 1.5 GPa, is considered for the first time for consolidating Bi2(Te,Se)3 alloys. Results from this study show that increasing the temperature leads to changes in chemical composition and causes noticeable grain growth. On the contrary, increasing pressure mainly causes improvements in densification. Overall, increments in these two parameters improve the ZT values, with the temperature parameter having a higher influence. The highest ZT of 0.69 at 160 °C was obtained for the sample hot-pressed at 350 °C and 1 GPa for 5 min, which is indeed an excellent and competitive value when compared with results reported for this n-type Bi2Te2.55Se0.45 composition.

The powder metallurgy (PM) route for the production of closed-cell metallic foams has recently received a significant amount of attention. One of the major issues is the non-uniform and non-spherical nature of the cells produced, which can negatively affect the mechanical behavior. The current paper uses the PM route to process metallic foams for the first time using novel Al-TiH2 foamable precursor “particles” (FPPs). The effect of FPP content (0–10 wt.%) on the developed foam structure of aluminum and its mechanical properties is investigated. An increase in FPP content results in a decline in product density by forming uniform and near-spherical cells. The main advantage of the FPPs is the localization of the blowing agent TiH2 particle content within Al-TiH2 composite particles (i.e., giving rise to a higher local TiH2 content), which has led to the production of pores with relatively high circularities even at very low overall TiH2 contents. The foams produced displayed energy absorption capacities of 10–25 MJ/m3 at 50% strain, and maximum energy absorption efficiencies ranging from 0.6–0.7 (for 40–60% closed cell content)

In this work, an in-situ Al3Ti–Al2O3 composite was optimally synthesized from raw powders via mechanical milling and conventional sintering processes. The strong influence of milling time on the promotion of the phase reaction between the initial TiO2 and Al materials was proven by using X-ray diffraction and surface morphology analysis. The obtained results showed that the milling process did not initiate any reaction between the raw TiO2 and Al materials. However, the milling process was important for creating a homogeneous powder mixture and refining the particle size of the powders. The Al3Ti–Al2O3 composites were completely formed after conventional sintering at 750°C for 30 min for a milling time of over 4 h. The highest obtained microhardness of the composite was approximately 130 HV, which was suggested to be related to the microstructure of the bulk composite specimen consisting of two main phases, the Al3Ti matrix and the Al2O3 particles dispersed in the matrix. A small portion of an unidentified phase, a Ti-rich compound, was found in the matrix together with a tiny fraction of AlTi3. We suggest that the optimal sintering process and mechanical milling are important key factors in fabricating bulk hardness Al3Ti–Al2O3 composite materials.

The cold spray technique is expected to effectively form a metallic coating with fine crystal grains originating from the microstructure of the original powder. We previously reported that a pure iron coating with fine crystal grains can be formed by the cold spray technique by using mechanically-milled pure iron powder. In this study, the tensile strength of the pure iron coating was investigated. The as-sprayed coating showed significantly low Young's modulus, tensile strength, and ductility owing to the low cohesion strength between particles. For tensile strength improvement, the coating was subjected to spark plasma sintering (SPS) treatment. As a result, the Young's modulus was considerably improved by the SPS treatments at 740 and 786°C; moreover, the tensile strength of the SPS-treated coating was approximately four times higher than that of the bulk material. In contrast, the ductility was not improved by the SPS treatment. The low ductility was likely attributed to the presence of Fe oxides at the particleparticle interface. [ABSTRACT FROM AUTHOR]

A low cost and scalable powder‐based method for producing nanoporous Ni is demonstrated, and the only processing by‐product is water vapor. This is achieved by creating a metal–matrix composite of Ni and NiO that is then reduced under dilute hydrogen to create pure Ni with nanocrystalline structure and nanoscale porosity. The technique is demonstrated in loose powder and in thin and bulk compacts with centimeter dimensions. These compacts can withstand extensive deformation without disintegrating, performing similarly to wrought Ni in specific strength. The unique processing strategy and resulting material can be readily extended to other metals and alloys. [ABSTRACT FROM AUTHOR]

The interest in studying the synthesis of an Al–Cr alloy system by non-equilibria processes is due to the formation of metastable or quasicrystalline phases when rapid solidification has been utilized. Similarly, the formation of quasicrystals has been reported to a much lesser extent when the mechanical alloying technique was applied. In the present research, a mixture of powders of Cr and Al (both elements with a purity of 99.99%) with compositions of Al-5 and 7.5 at. % Cr was subjected to a ball milling process. Afterwards, the powder mixture was subjected to a consolidation process, conducted by pressing and sintering processes. The X-ray diffraction analyses revealed that during 20 h of milling there was no formation of metastable or quasicrystalline second phases detected. In addition, the X-ray diffraction peaks revealed that as milling time increased, the nanometric grain size decreased, and once the sintering treatment was applied, the crystallite size decreased following the same tendency. The dislocation density was estimated using the size of nanometric grains; this computation revealed that the dislocation density grew throughout the ball milling process; even after sintering, the multiplication of dislocations prevailed following the same tendency. [ABSTRACT FROM AUTHOR]

This review aims to expose mechanical milling as an alternative method for generating copper-based particles (copper particles (CuP) and copper composites (CuC)); more specifically, via a top-down or bottom-up approach, on a lab-scale. This work will also highlight the different parameters that can affect the size distribution, the type, and the morphology of the obtained CuP or CuC, such as the type of mechanical mill, ball-to-powder ratios (BPR), the milling speed, milling time, and the milling environment, among others. This review analyzes various papers based on the Cu-based particle generation route, which begins with a pretreatment step, then mechanical milling, its approach (top-down or bottom-up), and the post-treatment. Finally, the characterization methods of the resulting CuP and CuC through mechanical milling are also discussed. [ABSTRACT FROM AUTHOR]

In this study, CuO–Cr2O3–PbO ternary nanocomposites (TNCs) with different atomic ratios of Cu:Cr:Pb (5:2:8, 5:4:6, 5:6:4, 5:8:2) were synthesized by means of efficient mechanical milling. As confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), uniform and impurity-free CuO–Cr2O3–PbO TNCs with an average grain size of 30 ​nm were successfully obtained. The catalytic properties of CuO–Cr2O3–PbO TNCs favorable for the pyrolysis of ammonium perchlorate (AP) were studied through thermogravimetric (TG) analysis and differential scanning calorimetry (DSC). The results show that TNC-8, which has an atomic ratio of 5:8:2 (Cu:Cr:Pb), exhibited the highest catalytic activity for the pyrolysis of AP when the pyrolytic temperature of AP decreased from 441.3 ​°C to 360.2 ​°C and the Gibbs free energy (ΔG≠) decreased from 199.8 ​kJ·​mol−1 to 175.2 ​kJ·​mol−1, as compared to CuO–Cr2O3–PbO nanocomposites with other atomic ratios.

We compared the hydrogenation and dehydrogenation properties of Mg-based alloys to which small amounts of transition elements (Ni and Ti), halides (TaF5 and VCl3), and complex hydrides (LiBH4 and NaAlH4) were added through grinding in a hydrogen atmosphere (reactive milling). Mg-1.25Ni-1.25Ti is one of the samples compared, having a composition of 97.5 wt.% Mg + 1.25 wt.% Ni and 1.25 wt.% Ti. Even though Mg-1.25Ni-1.25Ti did not have the highest initial hydrogenation rate, it had the largest quantities of hydrogen absorbed and released for 60 min and the highest initial dehydrogenation rate. In addition, Mg-1.25Ni-1.25Ti did not show the incubation period in the dehydrogenation. We thus investigated the hydrogenation and dehydrogenation properties of Mg-1.25Ni-1.25Ti in more detail. Activated Mg-1.25Ni-1.25Ti absorbed 5.91 wt.% H in 12 bar H2 and released 5.80 wt.% H in 1.0 bar H2 at 593 K for 60 min at n = 3. For 5 wt.% hydrogen absorption by Mg-1.25Ni-1.25Ti, 18.7 min was required at 593 K in 12 bar H2 at n = 3. Although only small amounts of Ni and Ti were added, the hydrogenation and dehydrogenation properties of Mg were greatly improved. Ni and Ti-added Mg had a higher initial dehydrogenation rate and a larger Hd (60 min) than only Ni-added Mg, suggesting that the TiH1.924 and NiTi formed in Mg-1.25Ni-1.25Ti play roles in the increases in the initial dehydrogenation rate and Hd (60 min), probably acting as active sites for the nucleation of the Mg-H solid solution phase.

The effect of mechanical activation of the mixture of Fe2O3-Co3O4-ZnO reagents on thermal synthesis of cobalt-zinc ferrite (Co0.5Zn0.5Fe2O4) was studied using X-ray powder diffraction and thermal analyses. The initial oxide powders were mixed using a Retsch Emax high energy ball mill to homogenize the mixture and enhance the reactivity. Mechanical activation was performed in air for 30 and 60 min. Thermal synthesis was performed at 900 °C for 4 h. X-ray diffraction analysis revealed an increase in the intensity of reflections that belong to spinel phases at increased rotational speed of the grinding vials and grinding duration. The patterns of formation of the final ferrite phase depending on the modes of mechanical pre-activation were showed by thermal analysis. It was shown that mechanical pre-activation of a mixture of initial reagents in a high-energy ball mill facilitates the formation of the ferrite phase of the given composition. The Curie temperature was determined for Co0.5Zn0.5Fe2O4 ferrite (~ 178 °C) by thermal synthesis. Kindly check and confirm whether the corresponding author is correctly identified. Corresponding author identified correctl [ABSTRACT FROM AUTHOR]

In this study, the surface of industrial pure iron was treated with atmospheric-controlled induction heating fine particle peening (AIH-FPP) using mechanical coating (MC) particles of carbon/steel obtained by mixing carbon powder and fine steel particles using mechanical milling. The surface modification effect and the mechanism of its effect were examined and considered by analyzing of the treated surface. Results showed that a modified layer in which carbon elements were diffused was formed near the treated surface by the AIH-FPP treatment using MC particles. In addition, by examining the influence of the treatment conditions on the formation of the modified layer by the design of experiments, the treatment temperature showed the most significant influence among the treatment temperature, peening time, and gas flow rate. The higher the treatment temperature, the deeper the carbon diffused layer. In addition, when treated at ≥1273 K, the microstructure near the surface became pearlite, and Vickers hardness increased. The time required for carbon diffusion in the AIH-FPP carburizing process using MC particles of carbon/steel was approximately the same as that of a general carburizing treatment using a reactive gas. In the AIH-FPP carburizing process, carbon is considered to be transferred from the particles to the surface, and the grain boundaries and dislocations increased by fine particle peening (FPP) are used as channels to diffuse inside the specimen. This mechanism is entirely different from the conventional carburizing methods. [ABSTRACT FROM AUTHOR]

Pure magnesium powders together with different amounts of process control agent (PCA) were mechanically milled (MMed) using a vibration ball mill. Stearic acid was used as PCA for the mechanical milling (MM) process. MMed powders were consolidated into bulk materials by spark plasma sintering (SPS). Changes in hardness and solid-state reactions of the MMed powders and the SPS materials have been examined by hardness measurements and an X-ray diffraction, respectively. No solid-state reaction was observed in the MMed powders even when the amount of PCA was increased. At PCA0.50 g, the Vickers hardness of the MMed powders and SPS materials did not improve with increasing a MM processing time. A maximum hardness value of 89 HV obtained in the SPS materials fabricated from MMed 24 h powders with PCA1.50 g. Formation of MgO by solidstate reaction was observed for the SPS materials consolidated from MMed 24 h powders with PCA1.00 g and 1.50 g. Formation of MgO was observed in the SPS materials by increasing the amount of PCA without heat treatments. Enhanced hardness of SPS materials could be attributable for both volume fraction of MgO and sintering temperatures. [ABSTRACT FROM AUTHOR]

Improving the ductile deformation behavior of Mg-SiC nanocomposites without compromising strength is critical to enhancing their mechanical properties. Mg-SiC nanocomposites are produced through mechanical milling, cold isostatic pressing, sintering, and hot extrusion processes. This study investigates the uniaxial stress–strain response and deformation behavior of the Mg-SiC nanocomposite compared to pure Mg samples with and without the milling process. The deformation behavior was investigated by two-dimensional (2D) digital image correlation (DIC) at two macroscopic and microscopic scales, employing light micrographs and in situ loading samples, respectively, in the scanning electron microscope. Compared to the pure Mg samples, the mechanical test results demonstrated a significant improvement in strength (80 MPa) and fracture strain (23.5%) of the Mg-SiC nanocomposite. The three-dimensional (3D) representative volume element (RVE) model revealed the particle dispersion effect on the mechanical properties of the nanocomposite. The RVE results demonstrate ductile deformation behavior in the sample with homogenous dispersion of SiC particles compared with the heterogeneous dispersion of SiC particles in Mg-SiC nanocomposite. The results demonstrated a good agreement between DIC and RVE predictions for Mg-SiC nanocomposites across macro- and microscales.

Mineral trioxide aggregates (MTA) are commonly used as endodontic filling materials but suffer from a long setting time and tooth discoloration. In the present study, the feasibility of using barium titanate (BTO) for discoloration and a calcium chloride (CaCl2) solution to shorten the setting time was investigated. BTO powder was prepared using high-energy ball milling for 3 h, followed by sintering at 700–1300 °C for 2 h. X-ray diffraction was used to examine the crystallinity and crystalline size of the as-milled and heat-treated powders. MTA-like cements were then prepared using 20–40 wt.% BTO as a radiopacifier and solidified using a 0–30% CaCl2 solution. The corresponding radiopacity, diametral tensile strength (DTS), initial and final setting times, and discoloration performance were examined. The experimental results showed that for the BTO powder prepared using a combination of mechanical milling and heat treatment, the crystallinity and crystalline size increased with the increasing sintering temperature. The BTO sintered at 1300 °C (i.e., BTO-13) exhibited the best radiopacity and DTS. The MTA-like cement supplemented with 30% BTO-13 and solidified with a 10% CaCl2 solution exhibited a radiopacity of 3.68 ± 0.24 mmAl and a DTS of 2.54 ± 0.28 MPa, respectively. In the accelerated discoloration examination using UV irradiation, the color difference was less than 1.6 and significantly lower than the clinically perceptible level (3.7). This novel MTA exhibiting a superior color stability, shortened setting time, and excellent biocompatibility has potential for use in endodontic applications.