The introduction of rapid solidification into alloys is an effective method for obtaining new metastable phases, including quasicrystals. Quasicrystals, characterized by forbidden high-order symmetry axes such as fivefold, threefold, and twofold, and long-range order other than periodic, are of great interest in the scientific community due to their unique properties.
This work is devoted to the study of the formation of the icosahedral quasicrystalline phase in the Al52Cu25.5Fe12.5Si10 alloy obtained by melt spinning. The aim of the study is to determine the optimal conditions for the formation of the quasicrystalline phase and to study its microstructure.
Experimental results show that at a spinning drum rotation speed of 40 m/s, a structure is formed consisting mainly of the icosahedral phase with a small amount of Al. A further increase in the drum rotation speed leads to a refinement of the icosahedral phase grains and an increase in its volume fraction.
The mechanical properties of the rapidly solidified Al52Cu25.5Fe12.5Si10 alloy containing the icosahedral phase are characterized by high hardness and brittleness. At the same time, the presence of the icosahedral phase contributes to an increase in the corrosion resistance of the alloy.
In this study, X-ray diffraction (XRD), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) were used. The obtained data indicate that rapid crystallization does not affect the phase structure of the Al52Cu25.5Fe12.5Si10 alloy. The introduction of silicon reduces the stability of the quasi-crystalline phase in the traditional cast Al52Cu25.5Fe12.5Si10 alloy.
Thermal stability of the quasi-crystalline phase in the alloy obtained by quenching from the melt is determined by the cooling rate. Moderate rapid crystallization rate can increase the thermal stability of the quasi-crystalline phase in the alloy produced by die casting.
An increase in the quenching rate leads to the transformation of the quasicrystalline phase into a cubic approximating phase, which leads to a decrease in the stability of the quasicrystalline structure. In addition, the phase transition temperature decreases with an increase in the silicon concentration in the Al(62−x)Cu25.5Fe12.5Six alloy.
In conclusion, rapid solidification is an effective method for obtaining icosahedral quasicrystalline phase in Al52Cu25.5Fe12.5Si10 alloy. The obtained results open up prospects for the development of new materials with unique properties based on quasicrystals.
Author: Yan Wang, Zhonghua Zhang, Haoran Geng, Zhongxi Yang
Institute: School of Materials Science and Engineering, Jinan University, 106 Jiwei Road, Jinan 250022, P.R. China, Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, 73 Jingshi Road, Jinan 250061, P.R. China