Cryogenic material have a wide range of applications in our life, such as deep-space exploration, applied superconductors, and gas industry. With the development of space technology and fusion reactor field, producing high-performance materials in the extreme conditions, especially at very low temperatures, has become a more and more impending mission. However, it's still a big challenge to produce metals and alloys with high-strength (σ_UTS>1GPa) and excellent ductility (ε_f>60%) at extremely low temperatures.
As a fire-new material, high-entropy alloys (HEAs) exhibit an extremely-broad philosophy on how to combine elements. The potent mixture strategy makes the opportunity to find something new and exciting very high.
The tensile test of CoCrFeNi high-entropy alloy at different temperatures.
Credit: ©Science China Press
In this circumstance, the service performance of high-entropy alloy under extremely condition inevitably becomes something we're curious about.
In this paper, the authors have assessed the mechanical response of the CoCrFeNi high-entropy alloy (see the results in Figure 1), and found that this alloy exhibit a high ultimate tensile strength of 1.26 GPa and elongation to failure of 62% at 4.2 K, which are the best among almost all of metallic materials, as shown in Figure 2.
This study witnesses the extensive deformation twinning and phase transformation from a face-centered cubic (FCC) structure to a hexagonal close-packed (HCP) structure are responsible for the superior mechanical performance at such low temperature.
Moreover, the serration feature appears in the stress-strain curves of this alloy at liquid-helium temperatures and the authors deduce the high-density twinning and phase transformation contribute to the serration feature, and that the FCC-HCP transition makes the serrated flow unstable.
The results of high-mechanical performance at low temperatures, phase transition, and serration, not only exhibit a significant breakthrough in the fundamental materials science, but also indicate HEAs' tremendous prospects and potential applications in the field of extreme cryogenic engineering.
YAN Bei | EurekAlert!
Looking at linkers helps to join the dots
10.07.2020 | King Abdullah University of Science & Technology (KAUST)
Goodbye Absorbers: High-Precision Laser Welding of Plastics
10.07.2020 | Fraunhofer-Institut für Lasertechnik ILT
Biochemists at Martin Luther University Halle-Wittenberg (MLU) have used a standard electron cryo-microscope to achieve surprisingly good images that are on par with those taken by far more sophisticated equipment. They have succeeded in determining the structure of ferritin almost at the atomic level. Their results were published in the journal "PLOS ONE".
Electron cryo-microscopy has become increasingly important in recent years, especially in shedding light on protein structures. The developers of the new...
New insight into the spin behavior in an exotic state of matter puts us closer to next-generation spintronic devices
Aside from the deep understanding of the natural world that quantum physics theory offers, scientists worldwide are working tirelessly to bring forth a...
Kiel physics team observed extremely fast electronic changes in real time in a special material class
In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...
Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.
Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....
Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.
Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...
07.07.2020 | Event News
02.07.2020 | Event News
19.05.2020 | Event News
13.07.2020 | Physics and Astronomy
13.07.2020 | Life Sciences
13.07.2020 | Life Sciences