Al¡VCu¡VSi alloy is widely applied in industry mainly as a light construction material. It is also a promising material for applications such as engine block and cylinder heads. It is important for designers to have an intimate knowledge of how Al¡VCu-Si alloy solidifies because its mechanical performance is usually controlled by solidification mechanism and microstructural characteristics. However, so far there has been little research on its rapid solidification mechanism under the extremely nonequilibrium condition.
In this work, Al80.4Cu13.6Si6 eutectic alloy was undercooled up to 147 K (0.18TE). Generally speaking, under the conventional solidification condition, a liquid aluminium alloy can be hardly undercooled because of oxidation. Dr. Ruan and Prof. Wei made it realized by choosing dehydrated B2O3 agent as a denucleating agent and providing a high-vacuum environment and special melting processing. In addition, the experimental parameters, such as cooling rate, superheating, and holding time, were controlled in order to get a wider undercooling range for comparison.
The undercooling level of alloy melt has a strong effect on its crystallization kinetics, structure morphology, and final physical and chemical properties. This study presents the microstructural characteristics of highly undercooled Al80.4Cu13.6Si6 ternary eutectic alloys. So far, most investigations on eutectic growth focus on binary alloy systems. The rapid solidification of undercooled ternary alloys involves the competitive nucleation and coupled growth of three eutectic phases from one liquid phase, which makes it more complicated than the case of binary alloys. The authors showed that the phase selection of Al80.4Cu13.6Si6 ternary eutectic alloy is influenced by undercooling, which makes the competitive nucleation and cooperative growth among ƒÑ(Al), (Si) and ƒá(CuAl2) phases become more drastic. Once undercooling exceeds 73 K, the primary phase will transform from (Al) dendrite to faceted (Si) block.
"This paper emphasizes the phase selection and microstructure formation of substantially undercooled ternary eutectic alloys. The result is of academic and practical significance." said one journal reviewer. A series of papers about rapid solidification of ternary eutectic alloys written by Dr. Ruan and Prof. Wei have been published in Chin. Sci. Bull., Sci. Chin. G, etc. "It enriched and expanded the research results on nonequilibrium solidification. It offered us new references to develop solidification and nonequilibrium phase transition theory," said another reviewer.
The authors are affiliated at Laboratory of Space Materials Science and Technology (LMSS) of NPU. This laboratory is conducting research mainly in three respects: materials processing under the space simulation condition, thermophysical properties of undercooled liquid alloys, and computational material science.
Y Ruan, B Wei | EurekAlert!
Further reports about: > Al¡VCu¡VSi > Substantial undercooling > computational material science > cylinder heads > engine block > high-vacuum environment > light construction material > materials processing > microstructural change > microstructural transition > nonequilibrium condition > ternary eutectic alloy
NASA's Fermi catches gamma-ray flashes from tropical storms
25.04.2017 | NASA/Goddard Space Flight Center
DGIST develops 20 times faster biosensor
24.04.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
25.04.2017 | Physics and Astronomy
25.04.2017 | Materials Sciences
25.04.2017 | Life Sciences