Nav: Home

Electron backscatter diffraction yields microstructure insights

November 14, 2017

WASHINGTON, D.C., Nov. 14, 2017 -- High-efficiency electric motors with tailored speed-torques, determined by their magnetic components, are essential for sustainable, successful electric automobile drive concepts. Soft magnetic core engineering plays a key role in these motors, where the main soft magnetic materials used today are electrical steels. But for higher-frequency applications, soft magnetic composites (SMCs) are also promising candidates.

Each of the different stages of motor construction, such as rolling, punching, laser cutting, or annealing, affects the material's microstructure and can lead to magnetic losses. Understanding the details of the microstructure is paramount to reaching higher efficiency for electrical motors. Due to the high rotational speed of traction drives, more than 5 percent of the electric energy produced is lost as heat.

In a paper published this week in the journal AIP Advances, from AIP Publishing, researchers at the University of Aalen in Germany created an advanced characterization method to closely examine microscale structural characteristics and changes during manufacturing processes using electron backscatter diffraction (EBSD).

"When you have deformations from machining, it is a great help to make the deformations visible," author and professor of physics of magnetic materials at Aalen University Dagmar Goll said. "In order to get deeper insight into the material's structure, electron backscatter diffraction is really useful. For example, grain size and shape, texture and degree of elastic strains and plastic deformations can be determined."

The authors compared the effects of various machining types on the microstructure of electrical steel. During machining, the cutting edge of the material is damaged, changing the crystallographic structure. "We evaluated the misorientations of grains in the material. So in the case of the cutting edge, we evaluated inhomogeneous areas with plastic deformations," Goll said. While these characteristics are microscopic, the cumulative effect in the material's structure adds up to a loss of efficiency in the final product.

"In the case of the powder metallurgical soft magnetic composites, which allow a higher degree of freedom in the design and construction of electric motors, we evaluated the recrystallization process during manufacturing as a function of compaction pressure, annealing parameters and powder particle size," author David Schuller said.

"We are improving the ratio between particle size and grain size distribution of the material," he said. "Depending on the annealing temperature, we can control grain growth and recrystallization in order to tailor the magnetic properties and minimize the magnetic losses."

The methodology developed by Schuller and colleagues provides a new tool to see exactly how, where and to what extent the crystalline structure is disrupted in machining processes and can be recovered during annealing. Their results show that EBSD is a powerful and versatile characterization technique for investigating and tailoring soft magnetic materials.
-end-
The article, "Analysis of soft magnetic materials by electron backscatter diffraction as a powerful tool," is authored by David Schuller, Dominic Hohs, Ralf Loeffler, Timo Bernthaler, Dagmar Goll and Gerhard Schneider. The article will appear in AIP Advances Nov. 14, 2017 [DOI: 10.1063/1.4994200]. After that date, it can be accessed at http://aip.scitation.org/doi/full/10.1063/1.4994200.

ABOUT THE JOURNAL

AIP Advances is a fully open access, online-only, peer-reviewed journal. It covers all areas of applied physical sciences. With its advanced web 2.0 functionality, the journal puts relevant content and discussion tools in the hands of the community to shape the direction of the physical sciences. See http://aipadvances.aip.org.

American Institute of Physics

Related Magnetic Materials Articles:

Magnetic memories of a metal world
Research deciphering the hidden magnetic messages encoded in a rare group of meteorites has helped secure nearly half a billion dollars of NASA funding for a journey to their parent asteroid -- the only known place in the solar system where scientists can examine directly what is probably a metallic core.
Wafer-thin magnetic materials developed for future quantum technologies
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified.
Even non-migratory birds use a magnetic compass
Not only migratory birds use a built-in magnetic compass to navigate correctly.
Computers create recipe for two new magnetic materials
Material scientists have predicted and built two new magnetic materials, atom-by-atom, using high-throughput computational models.
Manipulating magnetic textures
While the ability to easily control the magnetic properties of small electronic systems is highly desirable for future small electronics and data storage, an effective solution has proven to be extremely elusive.
Magnetic fields at the crossroads
Almost all information that exists in contemporary society is recorded in magnetic media, like hard drive disks.
When ultrafast laser pulse meets magnetic materials
The ultrafast laser-excited magnetization dynamics of ferromagnetic La0.67Sr0.33MnO3 (LSMO) thin films with BiFeO3 (BFO) coating layers grown by laser molecular beam epitaxy are investigated using the optical pump-probe technique.
Three magnetic states for each hole
Nanometer-scale magnetic perforated grids could create new possibilities for Computing.
Characterization of magnetic nanovortices simplified
Processors and storage media making use of tiny structures called 'skyrmions' could one day lead to the further miniaturization of IT devices and improve their energy efficiency significantly.
Perspectives on magnetic reconnection
Article describes latest research on magnetic reconnection.

Related Magnetic Materials Reading:

Magnetic Materials
by Rainer Hilzinger (Author), Werner Rodewald (Author)

At a practical level, this compendium reviews the basics of soft and hard magnetic materials, discusses the advantages of the different processing routes for the exploitation of the magnetic properties and hence assists in proper, fail-safe and economic application of magnetic materials. Essential guidelines and formulas for the calculation of the magnetic and electrical properties, temperature and long-term stability of permanent magnets, of inductive components and magnetic shielding are compiled. Selected fields of application and case studies illustrate the large diversity of technical... View Details


Magnetic Materials: Fundamentals and Applications
by Nicola A. Spaldin (Author)

Magnetic Materials is an excellent introduction to the basics of magnetism, magnetic materials and their applications in modern device technologies. Retaining the concise style of the original, this edition has been thoroughly revised to address significant developments in the field, including the improved understanding of basic magnetic phenomena, new classes of materials, and changes to device paradigms. With homework problems, solutions to selected problems and a detailed list of references, Magnetic Materials continues to be the ideal book for a one-semester course and as a self-study... View Details


Introduction to Magnetic Materials
by B. D. Cullity (Author), C. D. Graham (Author)

Introduction to Magnetic Materials, 2nd Edition covers the basics of magnetic quantities, magnetic devices, and materials used in practice. While retaining much of the original, this revision now covers SQUID and alternating gradient magnetometers, magnetic force microscope, Kerr effect, amorphous alloys, rare-earth magnets, SI Units alongside cgs units, and other up-to-date topics. In addition, the authors have added an entirely new chapter on information materials. The text presents materials at the practical rather than theoretical level, allowing for a physical, quantitative,... View Details


Magnetism and Magnetic Materials
by J. M. D. Coey (Author)

Covering basic physical concepts, experimental methods, and applications, this book is an indispensable text on the fascinating science of magnetism, and an invaluable source of practical reference data. Accessible, authoritative, and assuming undergraduate familiarity with quantum mechanics, electromagnetism and vectors, this textbook can be used on graduate courses. Emphasis is placed on practical calculations and numerical magnitudes - from nanoscale to astronomical scale - with a focus on modern manifestations, including spin electronic devices. Each self-contained chapter begins with a... View Details


Magnetic Materials: Fundamentals and Device Applications
by Nicola A. Spaldin (Author)

Magnetic materials are the foundation of multi-billion dollar industries and the focus of intensive research across many disciplines. This book covers the fundamentals, basic theories and applications of magnetism and conventional magnetic materials. Based on a lecture course given by Nicola Spaldin in the Materials Department at University of California, Santa Barbara, the book is ideal for a one- semester course in magnetic materials. It contains numerous homework problems and solutions. View Details


Introduction to Magnetism and Magnetic Materials, Third Edition
by David Jiles (Author)

A long overdue update, this edition of Introduction to Magnetism and Magnetic Materials is a complete revision of its predecessor. While it provides relatively minor updates to the first two sections, the third section contains vast updates to reflect the enormous progress made in applications in the past 15 years, particularly in magnetic recording. The book includes significant updates to soft magnetic materials, hard magnetic materials, magnetic data storage, and magnetic evaluation of materials. It also adds new information on magneto-transport, small particles, nanomagnetism,... View Details


Modern Magnetic Materials: Principles and Applications
by Robert C. O'Handley (Author)

A truly modern treatment of materials that can hold a magnetic field.
* Covers cutting-edge materials with many important technical applications.
* Includes examples and problems along with computer solutions. View Details


Magnetic Materials and 3D Finite Element Modeling
by João Pedro A. Bastos (Author), Nelson Sadowski (Author)

Magnetic Materials and 3D Finite Element Modeling explores material characterization and finite element modeling (FEM) applications. This book relates to electromagnetic analysis based on Maxwell’s equations and application of the finite element (FE) method to low frequency devices. A great source for senior undergraduate and graduate students in electromagnetics, it also supports industry professionals working in magnetics, electromagnetics, ferromagnetic materials science and electrical engineering.

The authors present current concepts on ferromagnetic material... View Details


Molecular Magnetic Materials: Concepts and Applications
by Barbara Sieklucka (Editor), Dawid Pinkowicz (Editor)

A comprehensive overview of this rapidly expanding interdisciplinary field of research.
After a short introduction to the basics of magnetism and molecular magnetism, the text goes on to cover specific properties of molecular magnetic materials as well as their current and future applications. Design strategies for acquiring molecular magnetic materials with desired physical properties are discussed, as are such multifunctional materials as high Tc magnets, chiral and luminescent magnets, magnetic sponges as well as photo- and piezo-switching magnets.
The result is an excellent... View Details


Handbook of Magnetic Materials, Volume 15
by K.H.J. Buschow (Author)

Volume 15 of the Handbook on the Properties of Magnetic Materials, as the preceding volumes, has a dual purpose. As a textbook it is intended to be of assistance to those who wish to be introduced to a given topic in the field of magnetism without the need to read the vast amount of literature published. As a work of reference it is intended for scientists active in magnetism research. To this dual purpose, Volume 15 of the Handbook is composed of topical review articles written by leading authorities. In each of these articles an extensive description is given in graphical as well as in... View Details

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Simple Solutions
Sometimes, the best solutions to complex problems are simple. But simple doesn't always mean easy. This hour, TED speakers describe the innovation and hard work that goes into achieving simplicity. Guests include designer Mileha Soneji, chef Sam Kass, sleep researcher Wendy Troxel, public health advocate Myriam Sidibe, and engineer Amos Winter.
Now Playing: Science for the People

#448 Pavlov (Rebroadcast)
This week, we're learning about the life and work of a groundbreaking physiologist whose work on learning and instinct is familiar worldwide, and almost universally misunderstood. We'll spend the hour with Daniel Todes, Ph.D, Professor of History of Medicine at The Johns Hopkins University, discussing his book "Ivan Pavlov: A Russian Life in Science."