Effect of the Compaction Parameters and Canning Material of Nanostructured Al-Powder Consolidated via Intense Plastic Straining Process

2008 ◽  
Author(s):  
H. G. Salem ◽  
M. Shamma
Keyword(s):  
Equal Channel Angular Extrusion ◽  
Average Particle Size ◽  
Research Work ◽  
High Strength ◽  
Processing Parameters ◽  
Average Particle ◽  
Particle Rotation ◽  
Sample Density ◽  
Powder Particles ◽  
Al 2024

Research groups around the world have reached common and contradicting conclusions regarding the behavior and properties of nanostructured materials. The aim of this research is to affirm the common findings by previous research, and support one of the currently proposed concepts of mechanical behavior based on processing and characterization of consolidated nanocrystalline micropowders of high strength/precipitation hardenable aluminum alloy using combined PM/intense plastic straining via Equal Channel angular Extrusion (ECAE). This research work investigated the effect of (a) Cold and hot consolidation of nanocrystalline Al-2124 micropowders into compacts with 4.0 h/d ratio and (b) Canning material used for encapsulating the compact rods for subsequent extrusion within the ECAE channels, and (c) the effect of ECAE number of passes and routes on the green compact properties. The effect of the processing parameters (compaction condition, extrusion temperature, strain rate) on the sample density, grain, subgrain and subcell sizes, and hardness was studied. Pure wrought and cast Cu, and casts Al-cans as well as Al-2024 wrought cans were used for canning of the consolidated powders. Green and hot compact rods were produced from 40μm average particle size Al-2124 powders with 53nm internal structure. Highest density consolidated rods were produced for the double sided cold compaction at 6σ (450MPa) over duration of 30min, while single sided compaction at similar pressure over 60min duration time of compaction and at temperature of 480°C produced the most dense and highest hardness hot compacts. Pure wrought Cu and cast Al are the most suitable canning material for room temperature ECAE of the Al-2124 green compacts. Non-isothermal heating during extrusion hindered the uniform warm deformation of the green and hot compacts canned in wrought Al-2024. Loose powder particles of the green compacts results in particle rotation while passing though the 90° angle intersecting channels of ECAE, and hence prevents full consolidation and densification of the produced product.

scholarly journals Facile Hydrothermal and Solvothermal Synthesis and Characterization of Nitrogen-Doped Carbon Dots from Palm Kernel Shell Precursor

2021 ◽  
Vol 11 (4) ◽  
pp. 1630
Author(s):  
Yakubu Newman Monday ◽  
Jaafar Abdullah ◽  
Nor Azah Yusof ◽  
Suraya Abdul Rashid ◽  
Rafidah Hanim Shueb
Keyword(s):  
Carbon Dots ◽  
Batch Reactor ◽  
Average Particle Size ◽  
Research Work ◽  
Palm Kernel ◽  
Average Particle ◽  
One Pot ◽  
Palm Kernel Shell ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon

Carbon dots (CDs), a nanomaterial synthesized from organic precursors rich in carbon content with excellent fluorescent property, are in high demand for many purposes, including sensing and biosensing applications. This research focused on preparing CDs from natural and abundant waste, palm kernel shells (PKS) obtained from palm oil biomass, aiming for sensing and biosensing applications. Ethylenediamine and L-phenylalanine doped CDs were produced via the hydrothermal and solvothermal methods using one-pot synthesis techniques in an autoclave batch reactor. The as-prepared N-CDs shows excellent photoluminescence (PL) property and a quantum yield (QY) of 13.7% for ethylenediamine (EDA) doped N-CDs (CDs-EDA) and 8.6% for L-phenylalanine (L-Ph) doped N-CDs (CDs-LPh) with an excitation/emission wavelength of 360 nm/450 nm. The transmission electron microscopy (TEM) images show the N-CDs have an average particle size of 2 nm for both CDs. UV-Visible spectrophotometric results showed C=C and C=O transition. FTIR results show and confirm the presence of functional groups, such as -OH, -C=O, -NH2 on the N-CDs, and the X-ray diffraction pattern showed that the N-CDs were crystalline, depicted with sharp peaks. This research work demonstrated that palm kernel shell biomass often thrown away as waste can produce CDs with excellent physicochemical properties.

scholarly journals Effect of Particle Size on Microstructure and Element Diffusion at the Interface of Tungsten Carbide/High Strength Steel Composites

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4164 ◽  
Author(s):  
Hongmei Zhang ◽  
Hongnan Li ◽  
Ling Yan ◽  
Chao Wang ◽  
Fangfang Ai ◽  
...  
Keyword(s):  
Particle Size ◽  
Tungsten Carbide ◽  
High Strength Steel ◽  
Average Particle Size ◽  
High Strength ◽  
Average Particle ◽  
Micro Hardness ◽  
Vacuum Sintering ◽  
Element Diffusion ◽  
Average Grain Size

The microstructure and micro-hardness of tungsten carbide/high strength steel (WC/HSS) composites with different particle sizes were analyzed by optical microscopy (OM), scanning electron microscopy (SEM), ultra-high temperature laser confocal microscopy (UTLCM) and micro-hardness testing. The composites were prepared by cold pressing and vacuum sintering. The results show that WC density tends to increase as the average grain size of WC decreases and the micro-hardness of WC increases with the decrease of WC particle size. The micro-hardness of WC near the bonding interface is higher than that in other regions. When the particle size of WC powder particles is 200 nm, a transition layer with a certain width is formed at the interface between WC and HSS, and the combination between the two materials is metallurgical. The iron element in the HSS matrix diffuses into the WC structure in contact with it, resulting in a fusion layer of a certain width, and the composite interface is relatively well bonded. When the average particle size of WC powder is 200 nm, W, Fe and Co elements significantly diffuse in the transition zone at the interface. With the increase of WC particle size, the trend of element diffusion decreases.

Investigating the Structure and Properties of the AlSi10Mg Alloy Manufactured by Means of Selective Laser Melting

2020 ◽  
pp. 71-85
Author(s):  
A.K. Karavaev ◽  
Yu.A. Puchkov
Keyword(s):  
Particle Size ◽  
Heat Affected Zone ◽  
Average Particle Size ◽  
Average Particle ◽  
General Corrosion ◽  
Pure Aluminium ◽  
Structure And Properties ◽  
Columnar Crystal ◽  
Sample Depth ◽  
Powder Particles

The paper investigates the structure and properties of samples made of ASP-25 AlSi10Mg, a Russian powder designed to replace expensive additive manufacturing powders of European origin featuring the same chemical composition. We detected that the particle size in the ASP-25 AlSi10Mg powder varies in the range of 7 to 50 μm, the average particle size being 23 μm for the standard deviation of 9.15 and dispersion of 83.7. On the surface of powder particles, we observed smaller satellite particles, individual aggregates, and particles of pure aluminium. We detected the following at the transition boundary between adjacent tracks: a columnar crystal zone and a heat-affected zone consisting of three layers of large, medium and small grains generated as a result of varied cooling conditions. These grains display different silicon lattice thicknesses along their boundaries. We detected no critical size pores (over 15 μm) or burning in the heat-affected zone. The fact that microhardness increases towards the sample edges and is non-monotonic over the transverse section is due to a range of factors acting simultaneously to create non-uniform temperature and force fields that cause differences in conditions of structure formation. Fractography studies of fractures in the AlSi10Mg alloy showed that the nature of failure varies along the sample depth. The central part of the sample, which is subjected to the highest thermal effects, shows clear signs of viscous failure along the main cracks developing along the boundaries of construction layers. We showed that the AlSi10Mg alloy is more resistant to pitting corrosion and general corrosion than the AK9сh (AK9ч) alloy

SUSTAINABLE ULTRA-HIGH-PERFORMANCE GLASS CONCRETE FOR INFRASTRUCTURES

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Arezki Tagnit-Hamou ◽  
Nancy A. Soliman
Keyword(s):  
High Performance ◽  
Glass Powder ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Low Cost ◽  
Research Work ◽  
High Strength ◽  
Quartz Powder ◽  
Ultra High Performance Concrete ◽  
Powder Particles

This paper presents research work on the development of a green type of ultra-high-performance concrete using ground glass powders with different degrees of fineness (UHPGC). This article presents the development of an innovative, low-cost, and sustainable UHPGC through the use of glass powder to replace cement, and quartz powder particles. An UHPGC with a compressive strength (fc) of up to 220 MPa was prepared and its fresh, and mechanical properties were investigated. The test results indicate that the fresh UHPGC properties were improved when the cement and quartz powder were replaced with non-absorptive glass powder particles. The strength improvement can be attributed to the glass powder’s pozzolanicity and to its mechanical performance (very high strength and elastic modulus of glass). A case study of using this UHPGC is presented through the design and construction of a footbridge. Erection of footbridge at University of Sherbrooke Campus using UHPGC is also presented as a full-scale application.

scholarly journals Influence of Glass Powder Size Sorting on Properties of Composite Systems

2016 ◽  
Vol 47 (1) ◽  
pp. 25-31
Author(s):  
K. Dědičová ◽  
P. Valášek
Keyword(s):  
Glass Powder ◽  
Adhesive Bonding ◽  
Raw Materials ◽  
Average Particle Size ◽  
Polymeric Materials ◽  
Average Particle ◽  
Powder Size ◽  
Size Sorting ◽  
Powder Particles ◽  
Size Of Particles

Abstract Glass powder ranks among the secondary raw materials, which can be used in the interaction with polymeric materials. In the present experiment the polymeric/epoxy particle composite with different sizes of glass powder particles is described. Such utilization of recyclable materials is environmental-friendly and should be preferred. The size of particles forming the filler of the described composites is one of the key characteristics affecting the mechanical properties. Due to the properties of the systems filled with glass powder, these materials can potentially be used in agriculture (renovations, adhesive bonding, cementing, etc.). In the experiment, glass powder was dimensionally sorted through sieves. Three fractions of glass powder with particles size of 0−30, 30−50, and 50−90 μm were created and utilized, the average particle size being 18.7, 38.7, and 72.6 μm, respectively. The interaction of the 18.7 μm particles did not lead to a statistically significant decrease of shear strength values in the interval 0−20 vol.%. The presence of glass powder, however, in all cases decreased tensile strength.

scholarly journals STUDY PARTICLE SIZE DISTRIBUTION OF ERODING POWDER LEAD BRONZES OBTAINED IN DISTILLED WATER

2018 ◽  
Vol 22 (4) ◽  
pp. 42-49
Author(s):  
E. V. Ageev ◽  
A. S. Pereverzev ◽  
A. S. Osminina ◽  
I. Yu. Grigorov
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Discharge Zone ◽  
Powder Materials ◽  
Average Particle ◽  
Distilled Water ◽  
Powder Particles ◽  
Local Exposure ◽  
Finely Dispersed Powder ◽  
Powder Lead

The article is devoted to the current problem of processing waste of conductive materials, in particular lead bronze, which accumulates in large quantities at enterprises. A promising method for processing any conductive material, characterized by wastelessness, ecological purity of the process, and low energy costs, is the method of electroerosive dispersion. The essence of the method of electroerosive dispersion is the destruction of current-conducting material as a result of local exposure to short-term electrical discharges between the electrodes. In the discharge zone, under high temperatures, heating, melting and partial evaporation of the material occurs, resulting in the formation of finely dispersed powder particles. At the same time, the electrical parameters of the installation will affect the productivity of the process for obtaining powder materials: the voltage at the electrodes, the capacitance of the discharge capacitors, and the repetition rate. The article presents the results of the analysis of particles of powdered lead bronze obtained by the method of electroerosive dispersion in distilled water from wastes, using the laser analyzer of particle sizes "Analysette 22 NanoTec". It has been experimentally established that the average particle size of powdered lead bronze is 9.73 μm, the arithmetic value is 9.731 μm. It was also found that the elongation coefficient (elongation) of particles with a size of 7.188 μm is 1.50.

Fine Copper Powders Production

2021 ◽  
Vol 410 ◽  
pp. 418-424
Author(s):  
Natalia E. Agarova ◽  
Lyubov M. Yakovleva ◽  
Roman S. Voinkov ◽  
Konstantin L. Timofeev
Keyword(s):  
Average Particle Size ◽  
Chloride Ions ◽  
Average Particle ◽  
Air Classification ◽  
Operating Modes ◽  
Electrolytic Copper Powder ◽  
Copper Powders ◽  
Powder Particles ◽  
Fine Copper

The article is devoted to the description of a method for producing electrolytic copper powder with an average particle size of 3 to 10 μm. In order to increase the proportion of the finely dispersed fraction during the electrolysis process, the composition of the electrolyte was changed. In particular, the content of chloride ions was increased from 6 to 53 mg/dm3. After the growth of the powder in industrial baths, its subsequent drying and sieving on vibrating screens, samples were obtained with a fraction of 5 μm content in the range from 3 to 38 %. Additionally, air classification of powders was carried out at various speeds of the classifier rotor from 800 to 2000 rpm. Based on the results of the study, the optimal ranges of the specific surface area and the size of the initial powder particles before classification, as well as the composition of the electrolyte and the operating modes of the classifier, were determined.

scholarly journals THE GREEN SYNTHESIS OF SILVER NANOPARTICLES OF ONION DNA AND SCREENING FOR IN VITRO ANTITYROSINASE ACTIVITY

2019 ◽  
pp. 271-275
Author(s):  
SNEHA THAKUR ◽  
KRISHNA MOHAN G
Keyword(s):  
Silver Nanoparticles ◽  
Nitrate Solution ◽  
Average Particle Size ◽  
Research Work ◽  
Local Market ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Antityrosinase Activity ◽  
Cubic Structure ◽  
Face Centered

Objective: The main objective of the research work is to evaluate the antityrosinase potential of onion DNA silver nanoparticles (AgNPs). Methods: The onions were procured from the local market and DNA was extracted from onions using detergent and methylated spirit. The isolated DNA was selected for synthesis of AgNPs which acts as capping and reducing agent. About 10 ml of the DNA extract was added to 90 ml of 0.1 N silver nitrate solution. After 24 h incubation, the solution turned dark brown, which indicates the formation of AgNPs. The synthesized DNA AgNPs were characterized by ultraviolet-visible, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and dynamic light scattering (DLS) studies. Results: The results revealed that the particles were uniform in shape with face-centered cubic structure. The particles are 153±20.4 nm in size and were no signs of agglomeration measured by DLS studies. The FTIR spectroscopy revealed B form of DNA along with strong N-H stretching, C=N stretching, and also asymmetric vibrations of phosphate groups characteristic for DNA molecule. The XRD studies revealed the face-centered cubic structure. SEM studies revealed the spherical structure with average particle size of 150±0.1 nm for single DNA nanoparticles. The onion DNA AgNPs were further investigated for its antityrosinase activity against the standard kojic acid and were to have anticancer potential nearer to the standard. Conclusion: From the results, it is evident that the synthesized onion DNA AgNPs have antityrosinase potential and can be further investigated for in vivo anticancer potential in future.

scholarly journals Effect of Dispersoids and Intermetallics on Hardening the Al-Si-Cu-Mg Cast Alloys

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
J. Hernandez-Sandoval ◽  
M. H. Abdelaziz ◽  
A. M. Samuel ◽  
H. W. Doty ◽  
F. H. Samuel
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Base Alloy ◽  
Average Particle Size ◽  
Research Work ◽  
Aging Treatment ◽  
Average Particle ◽  
Cast Aluminum ◽  
Poisoning Effect ◽  
Cast Alloys

The principal aim of the present research work was to compare the role of dispersoids Al2O3 (∼15 μm average particle size) and SiC (∼15 μm average particle size) with that offered by Zr- and Ni-based intermetallics (∼35–70 μm average particle size) on the hardening of cast aluminum 354 alloy (9.1% Si, 0.12% Fe, 1.8% Cu, 0.008% Mn, 0.6% Mg, and 87.6% Al) at ambient temperature. There is no observable poisoning effect on the refinement of grain size after the addition of Zr to the alloys investigated in this study. The tensile test results were examined in light of the microstructural features of the corresponding alloy samples. The contribution of the added dispersoids or Ni and Zr alloying elements on the tensile properties of the 354 alloys was determined employing ∆P plots (where P = Property, UTS, YS, or %El), using the base alloy (in the as-cast condition) as a reference point. The tensile results were supported by investigating the precipitation-hardening phases using scanning and transmission electron microscopy as well as examining the fracture surfaces of selected conditions applying field emission scanning electron microscopy. The results show that, in all cases, Al2Cu phase is the main hardening agent. The contribution of about 1.5 vol% of SiC or Al2O3 to the strength of the base alloy is higher than that offered by Zr- and Ni-based intermetallics, under the same aging treatment.

Interaction between small particles of cobalt, iron and nickel

1978 ◽  
Vol 36 (1) ◽  
pp. 582-583
Author(s):  
I. Hansson ◽  
A. Tholen
Keyword(s):  
Average Particle Size ◽  
Metal Particles ◽  
Average Particle ◽  
Single Particles ◽  
Small Particles ◽  
Particle Rotation ◽  
Strain Fields ◽  
Gas Atmosphere ◽  
Cobalt Iron ◽  
Curie Temperatures

A growing interest has recently been shown in small (< 100 nm) metal particles. Such particles are conveniently made by evaporation in an inert gas atmosphere (see eg. 1,2) and the average particle size is empirically found to increase both with pressure and evaporation temperature.A detailed study was presented earlier on the interaction between single particles of gold (3). The surface energy was found to be the driving force for the whole series of possible adhesion events which include elastic deformation with strain fields visible in the electron microscope (4), plastic deformation with twinning, relative particle rotation and sliding. Nobody has, however, convincingly reported at which position relative to the evaporation source and at what temperature the particle formation and interaction occur. It is the aim with this investigation to start elucidating these processes by using various ferromagnetic materials with different Curie temperatures. These particles have then, in a way, a memory of the actual processes.

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