scholarly journals Tying Processing Parameters to the Microstructure and Mechanical Properties of Nanostructured FeNiZr Consolidated via the Field Assisted Sintering Technique

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 436
Author(s):  
Sean J. Fudger ◽  
Thomas L. Luckenbaugh ◽  
Anthony J. Roberts ◽  
Chris D. Haines ◽  
Kris A. Darling
Keyword(s):  
Mechanical Response ◽  
Hold Time ◽  
Oxide Dispersion Strengthened ◽  
Processing Parameters ◽  
High Energy ◽  
Microstructural Coarsening ◽  
The Cost ◽  
Field Assisted Sintering ◽  
Hardness Values ◽  
Consolidation Temperature

An oxide-dispersion-strengthened (ODS) nanostructured FeNiZr alloy was fabricated via high energy mechanical alloying, and subsequently consolidated by the field assisted sintering technique (FAST). A range of input parameters: Temperature, hold time and pressure were evaluated in an effort to optimize the mechanical response of the material. Improvements in density, up to 98.6% of theoretical, were observed with increasing consolidation temperature and hold time at the cost of decreasing hardness values resulting from microstructural coarsening. Hardness values decreased from 650 to 275 HV by increasing processing temperatures from 750 to 1100 °C. The relationships between the varied processing parameters, microstructure and the experimentally measured yield and ultimate tensile strengths are discussed. Specifically, the effect of varying the temperature and hold time on the resulting porosity, as observed via scanning electron microscopy (SEM) in tensile and compression samples, is emphasized.

The Microstructure of Mechanically Alloyed Al-4Mg Alloy

1981 ◽  
Vol 39 ◽  
pp. 48-49
Author(s):  
Sung K. Kang
Keyword(s):  
Oxide Dispersion Strengthened ◽  
Processing Parameters ◽  
High Energy ◽  
Ingot Metallurgy ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Property Relations ◽  
Energy Ball ◽  
Alloy Properties

The mechanical alloying of powders by high-energy ball milling is one of the recent technologies for the production of heat-resistant oxide-dispersion-strengthened (ODS) alloys. This technique has been successfully applied to Fe-, Ni-, and Al-base alloys. The microstructure and properties of mechanically alloyed (MA) materials are quite different from those produced by conventional ingot metallurgy. Many questions remain unanswered about the structure-property relations of MA materials. The study of these relationships is difficult because of very small grain size and the presence of dispersoids, precipitates, dislocation substructure, and texture.A detailed investigation of the microstructure is necessary to understand the unique properties of these materials. In the present paper, some of the microstructural information about a MA Al-4%Mg alloy is reported. A study of the structure of the MA powders and the structure of the consolidated MA alloys is required in order to relate the processing parameters to the alloy properties. Various electron-optical and X-ray diffraction techniques have been employed for this purpose.

Janus – A New Approach to Air Combat Pilot Training

2019 ◽  
Vol 2019 (4) ◽  
pp. 7-22
Author(s):  
Georges Bridel ◽  
Zdobyslaw Goraj ◽  
Lukasz Kiszkowiak ◽  
Jean-Georges Brévot ◽  
Jean-Pierre Devaux ◽  
...  
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
High Energy ◽  
Training System ◽  
Embedded Sensors ◽  
Pilot Training ◽  
New Approach ◽  
Combat Aircraft ◽  
Air Combat ◽  
The Cost

Abstract Advanced jet training still relies on old concepts and solutions that are no longer efficient when considering the current and forthcoming changes in air combat. The cost of those old solutions to develop and maintain combat pilot skills are important, adding even more constraints to the training limitations. The requirement of having a trainer aircraft able to perform also light combat aircraft operational mission is adding unnecessary complexity and cost without any real operational advantages to air combat mission training. Thanks to emerging technologies, the JANUS project will study the feasibility of a brand-new concept of agile manoeuvrable training aircraft and an integrated training system, able to provide a live, virtual and constructive environment. The JANUS concept is based on a lightweight, low-cost, high energy aircraft associated to a ground based Integrated Training System providing simulated and emulated signals, simulated and real opponents, combined with real-time feedback on pilot’s physiological characteristics: traditionally embedded sensors are replaced with emulated signals, simulated opponents are proposed to the pilot, enabling out of sight engagement. JANUS is also providing new cost effective and more realistic solutions for “Red air aircraft” missions, organised in so-called “Aggressor Squadrons”.

scholarly journals Designing high energy density flow batteries by tuning active-material thermodynamics

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5432-5443
Author(s):  
Shyam K. Pahari ◽  
Tugba Ceren Gokoglan ◽  
Benjoe Rey B. Visayas ◽  
Jennifer Woehl ◽  
James A. Golen ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Energy Storage ◽  
Energy Density ◽  
Fossil Fuels ◽  
Active Material ◽  
High Energy ◽  
Theoretical Framework ◽  
High Energy Density ◽  
Density Flow ◽  
The Cost

With the cost of renewable energy near parity with fossil fuels, energy storage is paramount. We report a breakthrough on a bioinspired NRFB active-material, with greatly improved solubility, and place it in a predictive theoretical framework.

scholarly journals Understanding the Links between the Composition-Processing-Properties in New Formulations of HEAs Sintered by SPS

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 888
Author(s):  
Paula Alvaredo-Olmos ◽  
Jon Molina-Aldareguía ◽  
Alvaro Vaz-Romero ◽  
Estela Prieto ◽  
Jesús González-Julián ◽  
...  
Keyword(s):  
High Hardness ◽  
Processing Parameters ◽  
Heating Rates ◽  
High Entropy ◽  
Plasma Sintering ◽  
Mechanical Study ◽  
Spark Plasma ◽  
Processing Properties ◽  
Bcc Phase ◽  
Hardness Values

This work presents two new compositions of high entropy alloys (HEAs) that were designed with the aim of obtaining a body-centered cubic (BCC) phase with high hardness values and a moderate density. Sintering was performed using Spark Plasma Sintering (SPS) with different heating rates to determine the influence of the processing parameters on the phase formation. The microstructural study revealed that the presence of Ni in the composition promoted phase separation, and the mechanical study confirmed a clear influence on the mechanical properties of both the composition and heating rate. The combination of microscopy with compression and nanoindentation tests at room and high temperature made it possible to advance our understanding of the relationships between the composition, processing, and properties of this emerging group of alloys.

scholarly journals Factors Affecting the Metal Recovery Yield during Induction Melting of Aluminium Swarf

2012 ◽  
Vol 730-732 ◽  
pp. 781-786
Author(s):  
Hélder Puga ◽  
Joaquim Barbosa ◽  
Carlos Silva Ribeiro
Keyword(s):  
Processing Parameters ◽  
High Energy ◽  
Metal Recovery ◽  
Raw Material ◽  
Protective Atmosphere ◽  
Induction Melting ◽  
Recovery Rates ◽  
Recovery Yield ◽  
High Efficient ◽  
Machining Operations

Machining operations of cast parts usually generate considerable amounts of waste in the form of chips (usually 3–5% of the casting weight). Traditionally, swarf is sold to scrapers and remelters, but this option is quite expensive because the selling price is roughly 30% of the acquisition price of the commercial 2nd melt raw material. For most aluminium foundries that incorporate machining operations in their products, reusing aluminium chips as raw material for the melting stocks is perhaps the best option as waste management policy in what concerns to economical and technical aspects. Nevertheless, aluminium swarf is a low density product (0.25 kg/dm3) and is usually covered by a thin film of aluminium oxide and machining fluid. Melting such a product without suitable previous preparation leads to very low metal recovery rates, high energy consumption, gases and smoke generation and very low quality of the final product. During the last years, the authors have developed a high efficient and environmentally friend aluminium swarf recycling technique, using direct incorporation in aluminium melts. The influence of processing parameters, namely melt temperature and holding time, melting atmosphere, swarf briquetting pressure and melting charge composition in the metal recovery yield and dross generation was studied and characterized, and the optimal processing parameters were established. The microstructure of the final product obtained in those conditions was evaluated and is also presented. It is shown that the recycling efficiency depends on the swarf conditioning, the melting technique and the melt treatment methodology. Swarf moisture reduction, induction melting under protective atmosphere and a specially developed degassing technique were found the most important factors influencing the recycling process. By using the developed technique, cast ingots with microstructure and sanity similar to commercially available AlSi12Cu1 2nd melt raw material were successfully obtained with minimal dross formation and metal recovery rates around 90%, without using traditional salts and fluxes.

scholarly journals Multiscale Copper-µDiamond Nanostructured Composites

2012 ◽  
Vol 730-732 ◽  
pp. 925-930
Author(s):  
Daniela Nunes ◽  
Vanessa Livramento ◽  
Horácio Fernandes ◽  
Carlos Silva ◽  
Nobumitsu Shohoji ◽  
...  
Keyword(s):  
Pure Copper ◽  
Thermal Stabilization ◽  
Hot Extrusion ◽  
Processing Parameters ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optimal Processing ◽  
Novel Approach ◽  
Transmission Electron

Nanostructured copper-diamond composites can be tailored for thermal management applications at high temperature. A novel approach based on multiscale diamond dispersions is proposed for the production of this type of materials: a Cu-nDiamond composite produced by high-energy milling is used as a nanostructured matrix for further dispersion of micrometer sized diamond. The former offers strength and microstructural thermal stability while the latter provides high thermal conductivity. A series of Cu-nDiamond mixtures have been milled to define the minimum nanodiamond fraction suitable for matrix refinement and thermal stabilization. A refined matrix with homogenously dispersed nanoparticles could be obtained with 4 at.% nanodiamond for posterior mixture with mDiamond and subsequent consolidation. In order to define optimal processing parameters, consolidation by hot extrusion has been carried out for a Cu-nDiamond composite and, in parallel, for a mixture of pure copper and mDiamond. The materials produced were characterized by X-ray diffraction, scanning and transmission electron microscopy and microhardness measurements.

Processing Dense Hetero-Nanostructured Metallic Materials for Improved Strength/Ductility Balance through High Strain Deformation and Electrical Current Assisted Sintering (ECAS)

2009 ◽  
Vol 633-634 ◽  
pp. 559-567 ◽  
Author(s):  
Thierry Grosdidier ◽  
Núria Llorca-Isern
Keyword(s):  
High Strain ◽  
Milled Powder ◽  
Electrical Current ◽  
Processing Parameters ◽  
Metallic Materials ◽  
Bulk Materials ◽  
Multi Scale ◽  
Field Assisted Sintering ◽  
Y2o3 Addition ◽  
Powder Metallurgy Route

This paper has examined some recent findings concerning the processing of fully dense hetero-nanostructured materials (i.e. consisting of nano, ultrafine and micrometric grains) which can be produced by using the interplay between heavy deformation and recrystallization. By plastic deformation of bulk materials, an improved strength/ductility balance can be obtained directly by imparting high strain deformation (by ECAE) until the occurrence of recrystallization. Using a powder metallurgy route, the strong potential of electric field assisted sintering (ECAS) for producing multi-scale microstructures when a milled powder is used is also demonstrated. In this case, in addition to modify the classic processing parameters (time/temperature of ECAS), altering the nature of the milled powder - by Y2O3 addition during the milling stage - is also a good way to delay the onset of recrystallization and, thereby, increase the fraction of ultrafine grains.

scholarly journals Nanostructured Strontium-Doped Calcium Phosphate Cements: A Multifactorial Design

2021 ◽  
Vol 11 (5) ◽  
pp. 2075
Author(s):  
Massimiliano Dapporto ◽  
Davide Gardini ◽  
Anna Tampieri ◽  
Simone Sprio
Keyword(s):  
Calcium Phosphate ◽  
Setting Time ◽  
Processing Parameters ◽  
High Energy ◽  
Powder Particle Size ◽  
Extrusion Force ◽  
Precise Control ◽  
Calcium Phosphate Cements ◽  
Shear Mixing ◽  
Mixing Techniques

Calcium phosphate cements (CPCs) have been extensively studied in last decades as nanostructured biomaterials for the regeneration of bone defects, both for dental and orthopedic applications. However, the precise control of their handling properties (setting time, viscosity, and injectability) still represents a remarkable challenge because a complicated adjustment of multiple correlated processing parameters is requested, including powder particle size and the chemical composition of solid and liquid components. This study proposes, for the first time, a multifactorial investigation about the effects of powder and liquid variation on the final performance of Sr-doped apatitic CPCs, based on the Design of Experiment approach. In addition, the effects of two mixing techniques, hand spatula (low-energy) and planetary shear mixing (high-energy), on viscosity and extrusion force were compared. This work aims to shed light on the various steps involved in the processing of CPCs, thus enabling a more precise and tailored design of the device, based on the clinical need.

Plasma Spheroidized Alumina/Zircon Mixtures

2000 ◽  
Author(s):  
Y. Li ◽  
K.A. Khor
Keyword(s):  
Thermal Spraying ◽  
Processing Parameters ◽  
High Energy ◽  
Molten State ◽  
Composite Powders ◽  
Spray Process ◽  
Plasma Spheroidization ◽  
Plasma Spray Process ◽  
Energy Ball ◽  
Spheroidized Powder

Abstract The plasma-spray process is specified by the associated processing parameters, where these influence the properties of the resultant deposits. This article describes the preparation and processing of composite powders for use in thermal spraying by mixing high purity zircon and alumina powders. The spheroidized powder were obtained by high energy ball milling and rapid solidification from the molten state during plasma spraying. The article discusses the processes involved in spray drying and plasma spheroidization, describing thermal analysis and mullitization kinetics in the spheroidized alumina/zircon mixtures.

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