Controlling the Processing Parameters for Consolidation of Nanopowders into Bulk Nanostructured Material

2009 ◽  
pp. 11-22 ◽  
Author(s):  
A. Sadek ◽  
H. G. Salem
Keyword(s):  
Processing Parameters ◽  
Nanostructured Material ◽  
Bulk Nanostructured Material

scholarly journals Synthesis of Bulk Nanostructured DO22Superlattice of Ni3(Mo, Nb) with High Strength, High Ductility, and High Thermal Stability

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
H. M. Tawancy
Keyword(s):  
Thermal Stability ◽  
Parent Phase ◽  
Aging Treatment ◽  
High Strength ◽  
Nanostructured Material ◽  
High Thermal Stability ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
High Ductility ◽  
Bulk Nanostructured Material

We show that a bulk nanostructured material combining high strength, high ductility, and high thermal stability can be synthesized in a Ni-Mo-Nb alloy with composition approaching Ni3(Mo, Nb). By means of a simple aging treatment at700°C, the grains of the parent face-centered cubic phase are made to transform into nanosized ordered crystals with DO22superlattice maintaining a size of 10–20 nm after up to 100 hours of aging and corresponding room-temperature yield strength of 820 MPa and tensile ductility of 35%. Deformation of the superlattice is found to predominantly occur by twinning on{111}planes of the parent phase. It is concluded that, although the respective slip systems are suppressed, most of the twinning systems are preserved in the DO22superlattice enhancing the ductility.

Optimization of Plasma Spray Processing Parameters for Deposition of Nanostructured Coatings

2002 ◽  
Author(s):  
I. Ahmed ◽  
T. L. Bergman
Keyword(s):  
Thermal Processing ◽  
Liquid Fraction ◽  
Processing Parameters ◽  
Nanostructured Material ◽  
Processing Parameter ◽  
Spray Process ◽  
Conventional Material ◽  
Novel Method ◽  
Change Response ◽  
Thermally Sprayed

When nanostructured material is thermally sprayed to produce coatings, the retention of the original nanostructure that is engineered into the raw stock is a principal objective, along with production of some molten material in order to adhere the sprayed material to the surface being coated. Therefore, in contrast to spraying conventional material, complete melting of the nanostructured raw stock is to be avoided. In this study, the melting and re-solidification of sprayed material is correlated to a spray process parameter that has been introduced in the literature by others. Using computer modeling, processing of zirconia agglomerates with plasma spraying has been simulated. Transition regions of the phase change response of the material to the thermal processing conditions are identified. The retained nanostructure content and liquid fraction of the sprayed material is correlated to the particle diameters, as well as the thermal processing parameter. Finally, a novel method to produce desired coatings composed of partially molten sprayed material, by using a bimodal particle size distribution of the sprayed powder, is presented and discussed.

Effect of Milling Time and Annealing on the Mechanical Response of Mechanically Milled Aluminium

2012 ◽  
Vol 445 ◽  
pp. 815-820 ◽  
Author(s):  
Nesma T. Aboulkhair ◽  
Amal M. K. Esawi
Keyword(s):  
Milling Time ◽  
Mechanical Response ◽  
Nanostructured Material ◽  
Control Agent ◽  
Thermal Treatments ◽  
Compression Tests ◽  
Process Control Agent ◽  
Long Time ◽  
Bulk Nanostructured Material ◽  
Compressive Tests

Owing to its many exceptional properties, aluminium finds many applications in theaerospace, automotive, building and packaging industries. Enhancing its properties through alloyingor thermal treatments has been the focus of researchers’ interests for a long time. In this work, purealuminium powders were mechanically milled for up to 12 hrs and then were cold compacted andextruded to produce bulk nanostructured material. Both tensile and compressive tests wereconducted and the results compared. Post extrusion annealing treatments for up to 3 hrs wereconducted on additional samples.It was found that increasing the process control agent (PCA) content as well as the milling durationresulted in a finer microstructure and hence enhanced mechanical strength. This was accompaniedby a reduction in the ductility of the material. Moreover, compression tests revealed that thesamples are significantly more ductile in compression than in tension and that the decrease inductility with increase in milling time is less significant than in the case of tension. The differencein mechanical response is attributed to plastic instabilities. Annealing was found to enhance thetensile ductility of the samples without sacrificing strength.

scholarly journals New functional material: spark plasma sintered Si/SiO2 nanoparticles – fabrication and properties

RSC Advances ◽  
2019 ◽  
Vol 9 (29) ◽  
pp. 16746-16753
Author(s):  
M. V. Dorokhin ◽  
V. A. Gavva ◽  
M. V. Ved' ◽  
P. B. Demina ◽  
Yu M. Kuznetsov ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Sio2 Nanoparticles ◽  
Nanostructured Material ◽  
Functional Material ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Bulk Nanostructured Material ◽  
Silicon Nanopowder

A bulk nanostructured material based on oxidized silicon nanopowder was fabricated using a spark plasma sintering technique.

Investigation of mechanically activated field-activated pressure-assisted synthesis processing parameters for producing dense nanostructured FeAl

2003 ◽  
Vol 18 (10) ◽  
pp. 2331-2338 ◽  
Author(s):  
S. Paris ◽  
Ch. Valot ◽  
L. Gosmain ◽  
E. Gaffet ◽  
F. Bernard ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Density Measurement ◽  
Xrd Analysis ◽  
Processing Parameters ◽  
Nanostructured Material ◽  
Planetary Mill ◽  
Uniaxial Pressure ◽  
Mechanical Pressure ◽  
Electron Microscopic ◽  
Synthesis Conditions

The parameters of the mechanically activated field-activated pressure-assisted synthesis (MAFAPAS) process, which were recently developed and patented for producing dense nanostructured materials, were studied in the case of the B2-FeAl intermetallic. Based on x-ray diffraction (XRD) experiments, residual stresses XRD analysis, relative density measurement, and secondary-electron microscopic observations, the optimal synthesis conditions (time, current intensity, and pressure) were studied. Fe + Al powders were comilled in a specially designed planetary mill to obtain a mixture of reactants at the nanoscale without the formation of any product. The milled mixtures were then subjected to a high density of alternating current (60 Hz ac, total current 1250 or 1500 A), a uniaxial pressure (70 or 106 MPa), and different times (from 2 to 5 min). This work confirms the reproducibility of the MAFAPAS process, showing the essential role of the mechanical activation step to produce a pure nanostructured material. In addition, the composition and the microstructure of MAFAPAS end-products depended on the processing parameters (time, current density, mechanical pressure). In particular, it was observed that the process of simultaneous synthesis and consolidation of the product introduced a high level of residual stresses.

scholarly journals Effect of Ce Content on Properties of Al-Ce-Based Composites by Powder-in-Tube Method

2021 ◽  
Vol 5 (10) ◽  
pp. 255
Author(s):  
Mairym Vázquez ◽  
Oscar Marcelo Suárez ◽  
Michael Thompson ◽  
Haneul Jang ◽  
Na Gong ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermomechanical Processing ◽  
Hardness Test ◽  
Nanostructured Material ◽  
Liquid Phase Sintering ◽  
Elemental Powder ◽  
Before And After ◽  
Powder Samples ◽  
Bulk Nanostructured Material ◽  
Powder In Tube

Al-Ce based alloys have gained recent interest and have proven to have excellent strength without heat treatment and high thermal stability. Challenges with the production of Al-Ce samples from elemental powders arise due to the elemental material before alloying being susceptible to rapid oxidation. The methodology for making superconductive wire, powder-in-tube, was used as a consolidate Al and Ce elemental powder, and Al-8 wt % Ce-10 wt % Mg composite powder into bulk nanostructured material. Powder samples are fabricated in an inert controlled atmosphere, then sealed in a tube to avoid oxidation of powders. Therefore, most of the powder is used without much loss. We used 316 stainless-steel tubes as a sheathing material. For Al-xCe wt % (x = 8 to 14) samples of elemental powder, liquid phase sintering was used and for Al-Ce-Mg powder solid-state sintering. Characterization of the bulk consolidated material after sintering, and before and after heat treatment, was made using optical and Scanning Electron Microscope imaging, Energy Dispersive Spectroscopy, Microhardness and Rockwell Hardness test. We demonstrated that microstructure stability in Al-Ce-based specimens can be retained after thermomechanical processing. Densification was achieved and oxidation of powder was avoided in most samples. In addition, we found that Fe and Ni in the sheathing material react with Al in the process, and Ce concentration modifies the reactivity the sheath.

Microstructural Variations in Melt-Spun Rapidly Solidified Ribbons

1985 ◽  
Vol 43 ◽  
pp. 54-55
Author(s):  
L. A. Bendersky ◽  
W. J. Boettinger
Keyword(s):  
Solid State ◽  
Processing Parameters ◽  
Heat Extraction ◽  
Solid State Reactions ◽  
Careful Examination ◽  
Ion Milling ◽  
Melt Spun ◽  
Wheel Side ◽  
Rapidly Solidified ◽  
Heat Extraction Rate

Rapid solidification produces a wide variety of sub-micron scale microstructure. Generally, the microstructure depends on the imposed melt undercooling and heat extraction rate. The microstructure can vary strongly not only due to processing parameters changes but also during the process itself, as a result of recalescence. Hence, careful examination of different locations in rapidly solidified products should be performed. Additionally, post-solidification solid-state reactions can alter the microstructure.The objective of the present work is to demonstrate the strong microstructural changes in different regions of melt-spun ribbon for three different alloys. The locations of the analyzed structures were near the wheel side (W) and near the center (C) of the ribbons. The TEM specimens were prepared by selective electropolishing or ion milling.

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