Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How oxygen can enhance strength and ductility of high-entropy alloys

28.11.2018

Latest findings published in Nature

Researchers from the Max-Planck-Institut für Eisenforschung, Düsseldorf, and the University of Science and Technology Beijing discovered a new mechanism that enhances both the antagonistic strength and ductility in a high-entropy alloy.


Atom probe tomography reveals a large distribution of ordered oxygen complexes in the model high-entropy alloy investigated.

B. Gault, Max-Planck-Institut für Eisenforschung GmbH

The new mechanism is caused by the addition of oxygen in relatively high quantity, which alters the alloy’s microstructure and leads to an increase of strength by almost 50% and ductility of ca. 95%. The scientists published their latest findings in Nature.

Oxygen, which is usually neglected as an alloying element as it is known to cause embrittlement, is now added by 2.0 atomic percent in a model high entropy alloy (HEA) of TiZrHfNb.

The researchers studied the effect of oxygen on the microstructure of the HEA to understand the impact on strength and ductility.

They used different analysis techniques such as synchrotron high-energy X-ray diffraction, electron backscatter diffraction mapping and aberration corrected scanning transmission electron microscopy (STEM) high-angle annular dark field but could not find differences between the oxygen loaded HEA and a usual one.

Only STEM bright field and atom probe tomography revealed the main reason for the spectacular increase in strength: the oxygen is located at interstitial positions within agglomerations of lighter atom , i.e. Ti and Zr.

“We could reveal that the oxygen locates within zones containing only a handful of atoms that are enriched in Ti, and, to a lesser extent Zr. Within these zones, the oxygen is arranged in a highly ordered manner forming individual trapping barriers. At the same time the ductility is increased during deformation when these ordered complexes are cut by dislocations, which are the crystalline defect that carry the plasticity, and cause their multiplication and change the way they shear the crystalline lattice.”, explains Dr. Baptiste Gault, head of the “Atom Probe Tomography” group at the MPIE. The oxygen complexes act as small precipitates and cause a change from planar to wavy slip during deformation.

The presented alloy is a model system, exhibiting too little oxidation resistance. Research to improve their performance by adding Al, Si or Cr is ongoing. The interstitial complex strengthening mechanism could be forming in many other alloy classes beyond HEAs. The scientists are exploring other metallic systems in which the strengthening effects from these ordered complexes could be exploited, in particular alloys that are closer to engineering applications. The work was funded by the Natural Science Foundation of China.

Wissenschaftliche Ansprechpartner:

Dr. Baptiste Gault, gault@mpie.de

Originalpublikation:

Z. Lei, X. Liu, Yua. Wu, H. Wang, S. Jiang, S. Wang, X. Hui, Y. Wu, B. Gault, P. Kontis, D. Raabe, L. Gu, Q. Zhang, H. Chen, H. Wang, J. Liu, K. An, Q. Zeng, T. Nieh, Z. Lu
Enhanced strength and ductility in a high-entropy alloy via ordered oxygen complexes
Nature 563 (2018)
https://doi.org/10.1038/s41586-018-0685-y

Weitere Informationen:

https://www.mpie.de/3865505/nature-oxygen-hea

Yasmin Ahmed Salem M.A. | Max-Planck-Institut für Eisenforschung GmbH
Further information:
https://www.mpie.de/

More articles from Materials Sciences:

nachricht New material captures carbon dioxide
15.10.2019 | Kyoto University

nachricht Bayreuth researchers discover stable high-energy material
15.10.2019 | Universität Bayreuth

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

Im Focus: Controlling superconducting regions within an exotic metal

Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).

Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...

Im Focus: How Do the Strongest Magnets in the Universe Form?

How do some neutron stars become the strongest magnets in the Universe? A German-British team of astrophysicists has found a possible answer to the question of how these so-called magnetars form. Researchers from Heidelberg, Garching, and Oxford used large computer simulations to demonstrate how the merger of two stars creates strong magnetic fields. If such stars explode in supernovae, magnetars could result.

How Do the Strongest Magnets in the Universe Form?

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

 
Latest News

New material captures carbon dioxide

15.10.2019 | Materials Sciences

Drugs for better long-term treatment of poorly controlled asthma discovered

15.10.2019 | Interdisciplinary Research

Family of crop viruses revealed at high resolution for the first time

15.10.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>