By using a new grain mapping technique it was possible to determine the internal 3D structure of the material without destroying the sample. Afterwards, a crack was initiated in the stainless steel, and the scientists were able to study how the crack grew between the grains. This is the first time that such an experiment has used the 3D grain mapping technique, and the first results are published in the journal Science this week.
Cracks can appear in stainless steel components when stress or strain is combined with a corrosive environment that attacks sensitive grain boundaries. These cracks represent a critical failure mechanism. In power generation plants, certain grain boundaries can become sensitive during heat treatments or during fast neutron irradiation in nuclear power stations.
Most metals used for engineering are made up of many small crystals or grains. The scientists used a new technique called diffraction contrast tomography, developed at the ESRF, to obtain a 3D map of all grains in a section of a stainless steel wire measuring 0.4 mm in diameter. This map contained the shapes, positions, and orientations of 362 different grains. The next stage of the experiment involved putting the wire into a suitable corrosive liquid, and applying a load to cause microcracks to grow between grains. During the crack growth, 3D tomographic scans (of 30 minutes each) were made at intervals of between two hours and a few minutes to follow the progress of the crack. This is the first in-situ experiment of this kind to use non-destructive 3D grain mapping techniques.
“The cracks grew along the boundaries between the grains which we had mapped in 3D, and we could visualize both the growing crack and certain special boundaries that resist cracking”, explains Andrew King, corresponding author of the paper in Science. “Some of these resistant boundaries were not the ones that we expected".
The special, crack-resistant boundaries may be of key importance to the metallurgy industry. Materials containing more of these boundaries are also more resistant to this type of cracking. Being able to study crack growth in-situ will allow scientists to understand what types of grain structures will give the best performing materials, leading, for example, to more efficient and safer power plants, and more generally to more lightweight alloys in other sectors of metallurgy and engineering.
Montserrat Capellas | alfa
Tunable diamond string may hold key to quantum memory
23.05.2018 | Harvard John A. Paulson School of Engineering and Applied Sciences
NIST puts the optical microscope under the microscope to achieve atomic accuracy
23.05.2018 | National Institute of Standards and Technology (NIST)
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
23.05.2018 | Life Sciences
23.05.2018 | Life Sciences
23.05.2018 | Physics and Astronomy