Mechanical alloying (MA) is a solid-state powder processng technique involving repeated welding, fracturing, and rewelding of powder particles in a high-energy ball mill. Originally developed to produce oxide-dispersion strengthened (ODS) nickel- and iron-base superalloys for applications in the aerospace industry, MA has now been shown to be capable of synthesizing a variety of equilibrium and non-equilibrium alloy phases starting from blended elemental or prealloyed powders. The non-equilibrium phases synthesized include supersaturated solid solutions, metastable crystalline and quasicrystalline phases, nanostructures, and amorphous alloys. Recent advances in these areas and also on disordering of ordered intermetallics and mechanochemical synthesis of materials have been critically reviewed after discussing the process and process variables involved in MA. The often vexing problem of powder contamination has been analyzed and methods have been suggested to avoid/minimize it. The present understanding of the modeling of the MA process has also been discussed. The present and potential applications of MA are described. Wherever possible, comparisons have been made on the product phases obtained by MA with those of rapid solidification processing, another non-equilibrium processing technique.

Mechanical Alloying And Milling

We report the creation of a nanoscale electrochemical device inside a transmission electron microscope--consisting of a single tin dioxide (SnO(2)) nanowire anode, an ionic liquid electrolyte, and a bulk lithium cobalt dioxide (LiCoO(2)) cathode--and the in situ observation of the lithiation of the SnO(2) nanowire during electrochemical charging. Upon charging, a reaction front propagated progressively along the nanowire, causing the nanowire to swell, elongate, and spiral. The reaction front is a "Medusa zone" containing a high density of mobile dislocations, which are continuously nucleated and absorbed at the moving front. This dislocation cloud indicates large in-plane misfit stresses and is a structural precursor to electrochemically driven solid-state amorphization. Because lithiation-induced volume expansion, plasticity, and pulverization of electrode materials are the major mechanical effects that plague the performance and lifetime of high-capacity anodes in lithium-ion batteries, our observations provide important mechanistic insight for the design of advanced batteries.

https://science.sciencemag.org/content/sci/330/6010/1515.full.pdf

In Situ Observation of the Electrochemical Lithiation of a Single SnO2 Nanowire Electrode

The aim of this review article on recent developments of mechanochemistry (nowadays established as a part of chemistry) is to provide a comprehensive overview of advances achieved in the field of atomistic processes, phase transformations, simple and multicomponent nanosystems and peculiarities of mechanochemical reactions. Industrial aspects with successful penetration into fields like materials engineering, heterogeneous catalysis and extractive metallurgy are also reviewed. The hallmarks of mechanochemistry include influencing reactivity of solids by the presence of solid-state defects, interphases and relaxation phenomena, enabling processes to take place under non-equilibrium conditions, creating a well-crystallized core of nanoparticles with disordered near-surface shell regions and performing simple dry time-convenient one-step syntheses. Underlying these hallmarks are technological consequences like preparing new nanomaterials with the desired properties or producing these materials in a reproducible way with high yield and under simple and easy operating conditions. The last but not least hallmark is enabling work under environmentally friendly and essentially waste-free conditions (822 references).

/pdf/hallmarks-of-mechanochemistry-from-nanoparticles-to-5cyjx2wiue.pdf

Hallmarks of mechanochemistry: From nanoparticles to technology

Recently a significant figure-of-merit (ZT) improvement in the most-studied existing thermoelectric materials has been achieved by creating nanograins and nanostructures in the grains using the combination of high-energy ball milling and a direct-current-induced hot-press process. Thermoelectric transport measurements, coupled with microstructure studies and theoretical modeling, show that the ZT improvement is the result of low lattice thermal conductivity due to the increased phonon scattering by grain boundaries and structural defects. In this article, the synthesis process and the relationship between the microstructures and the thermoelectric properties of the nanostructured thermoelectric bulk materials with an enhanced ZT value are reviewed. It is expected that the nanostructured materials described here will be useful for a variety of applications such as waste heat recovery, solar energy conversion, and environmentally friendly refrigeration.

Enhancement of Thermoelectric Figure-of-Merit by a Bulk Nanostructuring Approach

Processing of advanced materials using high-energy mechanical milling

Structural changes in stoichiometric CoGa during mechanical attrition in a high-energy ball mill were monitored by measurements of magnetic properties and lattice parameter. The high-field magnetization increases, whereas the lattice parameter decreases as a function of milling time. For long milling times, values of both parameters saturate. The results are interpreted by the generation of atomic triple-defect disorder, also characteristic of this compound in equilibrium at high temperatures: antisite Co atoms in combination with vacancies on the Co sublattice in a 1:2 ratio. By comparison to the magnetic properties of ${\mathrm{Co}}_{\mathit{x}}$${\mathrm{Ga}}_{100\mathrm{\ensuremath{-}}\mathit{x}}$ compounds with excess Co, the fractions of antisite Co atoms and vacancies are derived. On the basis of these values, the decrease of the lattice parameter can be calculated and compared to the actual measurement. The good agreement proves that, by the apparently crude technique of mechanical attrition, well-defined nonequilbrium states in intermetallic compounds can be generated.

/pdf/mechanical-attrition-and-magnetic-properties-of-cscl-1zewewdwno.pdf

Mechanical attrition and magnetic properties of CsCl-structure Co-Ga.

Amorphous Ni61Zr39 powder was prepared by grinding the two-phase crystalline alloy with a nominal composition of 61 at.% Ni and 39 at.% Zr. The X-ray diffraction pattern, the crystallization behaviour and magnetic properties were compared with results known from melt-spun NixZr1-x and amorphous Ni-Zr powder prepared by mechanical alloying.

The Preparation of Amorphous Ni-Zr Powder by Grinding the Crystalline Alloy

The Miedema-Niessen model for the volume effects which occur when two transition metals are alloyed is applied to the fast diffusion of metallic impurities in metals. The use of the model is also extended to other metallic systems. A correlation is found between fast diffusivities and the volumes corrected using this model. A similar correlation is found for the activation volumes for the diffusion of impurities in lead. The difference in the diffusion behaviour of gold and silver, which have equal uncorrected volumes, can be explained. It can be understood why gold is a fast diffuser in lead, praseodymium, thallium, indium and zinc, but not in γ-U although other impurities are fast diffusers in this metal. Predictions are made for other fast-diffusing systems.

Fast metal impurity diffusion in metals and the Miedema model

The stoichiometric intermetallic compound CoAl with the CsCl-structure was subjected to ball milling. Structural changes during ball milling were studied by measurements of the magnetization and the lattice parameter. The behaviour of Coal upon milling turns out to be quite similar to that of CoGa. The increase of the magnetization and the decrease of the lattice parameter with the milling time show that, similar to CoGa, triple-defect disorder is generated by ball milling. By comparing the measured magnetization to the magnetization of CoxAl100−x compounds with excess Co, the concentration of defects is derived for milled samples. In order to interpret our results, the existing experimental data of lattice parameters, X-ray densities calculated from the lattice parameters and macroscopic densities for CoxAl100−x compounds were analyzed according to Edelin's equations. The defect volumes for vacancies and anti-site atoms obtained by fitting these experimental data have reasonable values. By means of the defect concentrations obtained from our magnetization measurements and the defect volumes by fitting the experimental data, the change of the lattice parameter was calculated by means of Edelin's equation. The agreement between the calculated lattice parameter and the measured lattice parameter is quite satisfactory.

Atomic disorder induced by mechanical milling in the intermetallic compound CoAl

It is found that amorphization of Ni-Zr alloys by different milling techniques leads to different amorphization reactions. The amorphous alloy is formed directly from the elements when a ball mill on a vibrating frame is used. In contrast, when our planetary ball mill is used, crystalline intermetallic compounds appear as intermediate products in the amorphization reaction. The composition range of the amorphous Ni-Zr alloy is also different when the different milling techniques are used. The crystallization temperature of the amorphous Ni-Zr alloy is independent of the preparation technique.

Differences in the amorphization reaction by mechanical alloying of Ni-Zr resulting from different ball-milling techniques

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Hans Bakker

Author Tools

Chat about Author