[China Aluminum Industry Network] Aluminum-based amorphous alloys have attracted much attention due to their high specific strength and excellent corrosion resistance. Lightweight component materials have great development prospects in aviation, aerospace and other fields. However, the low glass forming ability of the aluminum-based amorphous alloy system is a bottleneck that restricts its engineering application.
Institute of Metals Shenyang National Institute of Materials Science (Union) Laboratory of Non-Equilibrium Metal Materials Wang Jianqiang, Research Fellow The Task Force teamed with Prof. Marne Professor of Johns Hopkins University in the United States, and conducted many years in the structure and glass forming ability of Al-based metallic glass. Research and exploration. In the Al-TM (transition metal)-RE (rare earth)-based ternary alloy system, the composition of the alloy was designed by coupling the cluster structure of dense clusters with TM and RE as solute centers. In the Al-Ni-Co-Y-La five-element alloy system, a 1 mm diameter aluminum-based metallic glass rod (aluminum content of 86 at.%) was obtained. This is the first time in the world that an aluminum-based bulk material has been produced by direct melt casting to produce a single amorphous phase, which has attracted widespread attention from researchers at home and abroad (more than 150 references so far). On this basis, recently we started with the two aspects of composition design and preparation process to further enhance its glass forming ability.
Understanding the mechanism of the influence of microalloying elements on the forming ability helps to design and optimize the alloy composition. Al-TM-RE amorphous alloy glass forming ability is very sensitive to the micro-component addition, however its mechanism of action is unclear. They studied their effects from the electronic structure level. On the one hand, by the effect of electron orbital hybridization between Al atoms and TM atoms, the addition of TM (for example, Co) can change the diameter of the Fermi surface; on the other hand, it adjusts the Al atoms and the RE atoms. Between static structures, the addition of trace RE (for example, La) atoms can change the size of the pseudo Brillouin zone. When the interaction between the two is the immersion of the Fermi surface in the metallic glass structure and the pseudo Brillouin zone (2KF=KP), the density of electronic states at the Fermi surface is low, and the overall metallic glass structure is relatively stable. Strong ability to form. Therefore, the alloy composition of the glass forming ability that has so far been excellent, that is, Al86Ni6.75Co2.25Y3.25La1.75, was molded to obtain a completely amorphous structural rod having a diameter of 1.5 mm (see Acta Mater, 108 (2016) 143 -151).
The above research work has been funded and supported by the key projects of the National Natural Science Foundation of China and the key R&D projects of the Ministry of Science and Technology.
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