Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Materials research with antiparticles: Unravelling the secret of nanocrystalline materials

Nanocrystalline materials rely on imperfection. Structural defects are responsible for their unusual material properties. Copyright Graz University of Technology
Nanocrystalline materials rely on imperfection. Structural defects are responsible for their unusual material properties. Copyright Graz University of Technology

Abstract:
Certain structural defects in materials are what make innovative nanocrystalline bulk metals very hard and yet readily malleable. As these defects are found at the atomic level of the metal structure they are difficult to investigate in experiments. However, Austrian scientists have recently taken a significant step towards understanding such atomic defects. They succeeded in doing so by combining two special methods in a project funded by the Austrian Science Fund FWF. The results have now been published in the renowned scientific journal Physical Review Letters.

Materials research with antiparticles: Unravelling the secret of nanocrystalline materials

Vienna | Posted on November 29th, 2010

Extremely hard but still easily malleable - the properties of the so-called nanocrystalline bulk metals give rise to many questions among physicists. Scientists at Graz University of Technology have finally managed to answer some of those questions through experiments.

The scientists set out to monitor the structural changes in the metals in real time. They were thus able to conclude that atomic defects are a central cause of the interesting physical material properties.

Nanocrystalline metals consist of countless crystallites (grains), which are mostly smaller than one hundred nanometres - and the smaller the grain, the more solid is the metal. The structure of nanocrystalline metals is actually very regular: the atoms in the grains lie tightly packed in rank and file. However, when the metals are produced, atomic defects are involuntarily introduced which disturb the atomic order within the grains. For example, certain layers are not located directly on top of each other: some atoms are missing or rows are misaligned. Austrian materials physicists have now produced the first experimental evidence of these effects, which are closely related to the mechanical properties. They have published their results in the journal Physical Review Letters, where they describe how the combination of two special methods can be used to closely examine atomic defects.

Spy attacks on metals

As atomic defects on the nanoscale are difficult to spot, the scientists worked with so-called positrons. Dr. Wolfgang Sprengel from Graz University of Technology explains: "A positron is a subatomic particle that is almost identical to the electron, with one difference: it is positively charged. If a positron and an electron meet, they annihilate each other. In the places where atomic defects are present, there are fewer electrons and therefore fewer occurrences of annihilation. The positrons therefore serve as spies that deliver detailed information about the atomic defects. We have used this effect to analyse the fast processes of atomic defects in metals." To carry out the experiments, the scientists availed themselves of the FRM II research reactor at the Technische Universität München (TUM), where they deployed the positron beam with the highest intensity in the world.

Two methods, one result

In addition to the positron-electron annihilation, macroscopic length-change measurements were made upon annihilation of the defects - by means of dilatometry. This combination of dilatometry and positron-electron annihilation is a first of its kind and it delivered the evidence that some of the seemingly mysterious physical properties of the nanocrystalline bulk metals can be attributed to these structural defects. The cause of the defects can be found in the production background of the metals. Nanocrystalline bulk metals are produced using very complex methods - such as high-pressure torsion (Erich Schmidt Institute Leoben) - which give rise to the atomic defects.

The FWF project headed by Dr. Roland Würschum is carried out in close cooperation with the University of Vienna and the Erich Schmidt Institute in Leoben, and is also closely linked to the National Research Network (NFN) on nanocrystalline bulk metals. The project has enabled a better understanding of fundamental principles, which is essential for the application of these innovative materials.

Original publikation:
In situ probing of fast defect annealing in Cu and Ni with a high-intensity positron beam. B. Oberdorfer, E-M. Steyskal, W. Sprengel, W. Puff, P. Pikart, C. Hugenschmidt, M. Zehetbauer, R. Pippan, R. Wüschum. Published September 28, 2010. Physical Review Letters 105, 146101. DOI: 10.1103/PhysRevLett.105.146101.

####

For more information, please click here

Contacts:
Scientific Contact
Univ.-Prof. Dr. Roland Würschum
Technische Universität Graz
Institut für Materialphysik
Petersgasse 16/IV
8010 Graz
T +43 / 316 / 873 - 8481
E

Austrian Science Fund FWF
Mag. Stefan Bernhardt
Haus der Forschung
Sensengasse 1
1090 Vienna, Austria
T +43 / 1 / 505 67 40 - 8111
E

Copy Editing & Distribution
PR&D – Public Relations for Research & Education
Mariannengasse 8
1090 Vienna, Austria
T +43 / 1 / 505 70 44
E
W www.prd.at

Copyright © Austrian Science Fund

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

A 'movie' of ultrafast rotating molecules at a hundred billion per second: A quantum wave-like nature was successfully observed in rotating nitrogen molecules July 4th, 2015

New Biosensor Produced in Iran to Detect Effective Drugs in Cancer Treatment July 4th, 2015

Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods July 3rd, 2015

Pioneering Southampton scientist awarded prestigious physics medal July 3rd, 2015

Govt.-Legislation/Regulation/Funding/Policy

New technology using silver may hold key to electronics advances July 2nd, 2015

NIST Group Maps Distribution of Carbon Nanotubes in Composite Materials July 2nd, 2015

Influential Interfaces Lead to Advances in Organic Spintronics July 1st, 2015

NIST ‘How-To’ Website Documents Procedures for Nano-EHS Research and Testing July 1st, 2015

Academic/Education

Oxford Instruments’ TritonXL Cryofree dilution refrigerator selected for the Oxford NQIT Quantum Technology Hub project June 30th, 2015

Rice University boots up powerful microscopes: New electron microscopes will capture images at subnanometer resolution June 29th, 2015

Six top Catalan research centres constitute ‘The Barcelona Institute of Science and Technology’ to pursue a joint scientific endeavour June 27th, 2015

Lancaster University revolutionary quantum technology research receives funding boost June 22nd, 2015

Discoveries

A 'movie' of ultrafast rotating molecules at a hundred billion per second: A quantum wave-like nature was successfully observed in rotating nitrogen molecules July 4th, 2015

New Biosensor Produced in Iran to Detect Effective Drugs in Cancer Treatment July 4th, 2015

Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods July 3rd, 2015

Groundbreaking research to help control liquids at micro and nano scales July 3rd, 2015

Materials/Metamaterials

Pioneering Southampton scientist awarded prestigious physics medal July 3rd, 2015

New technology using silver may hold key to electronics advances July 2nd, 2015

NIST Group Maps Distribution of Carbon Nanotubes in Composite Materials July 2nd, 2015

Proposed TSCA Nanomaterial Rule ‘Premature’, Says Former EPA Toxicologist July 1st, 2015

Announcements

A 'movie' of ultrafast rotating molecules at a hundred billion per second: A quantum wave-like nature was successfully observed in rotating nitrogen molecules July 4th, 2015

New Biosensor Produced in Iran to Detect Effective Drugs in Cancer Treatment July 4th, 2015

Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods July 3rd, 2015

Pioneering Southampton scientist awarded prestigious physics medal July 3rd, 2015

Tools

A 'movie' of ultrafast rotating molecules at a hundred billion per second: A quantum wave-like nature was successfully observed in rotating nitrogen molecules July 4th, 2015

Clues to inner atomic life from subtle light-emission shifts: Hyperfine structure of light absorption by short-lived cadmium atom isotopes reveals characteristics of the nucleus that matter for high precision detection methods July 3rd, 2015

Nanometrics to Announce Second Quarter Financial Results on July 23, 2015 July 2nd, 2015

NIST ‘How-To’ Website Documents Procedures for Nano-EHS Research and Testing July 1st, 2015

Research partnerships

Groundbreaking research to help control liquids at micro and nano scales July 3rd, 2015

Producing spin-entangled electrons July 2nd, 2015

Harris & Harris Group Portfolio Company, AgBiome, Announces Partnership to Accelerate the Discovery of Next Generation Insect-Resistant Crops July 1st, 2015

Leti Announces Launch of First European Nanomedicine Characterisation Laboratory: Project Combines Expertise of 9 Partners in 8 Countries to Foster Nanomedicine Innovation and Facilitate Regulatory Approval July 1st, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project