skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Formation of the icosahedral quasicrystalline phase in a rapidly solidified Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy

Abstract

In the present work, the effect of wheel speed (quenching rate) on the formation of the quasicrystalline phase in a rapidly solidified Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy has been investigated using X-ray diffraction (XRD), differential thermal analysis (DTA), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results show that rapid solidification has no effect on the phase constitution of the Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy. The addition of Si decreases the stability of the quasicrystalline phase in the conventionally cast Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy. The thermal stability of the quasicrystalline phase in the melt-spun alloy depends upon the quenching rate. Moderate-rate rapid solidification can improve the thermal stability of the quasicrystalline phase in the melt-spun alloy. Higher quenching rate instigates the transformation of the quasicrystalline phase into the cubic approximant phase and decreases the stability of the quasicrystalline phase. Furthermore, the transformation temperature decreases with increasing Si addition into the Al{sub (62-x)}Cu{sub 25.5}Fe{sub 12.5}Si{sub x}.

Authors:
 [1];  [2];  [1];  [1]
  1. School of Materials Science and Engineering, Jinan University, 106 Jiwei Road, Jinan 250022 (China)
  2. Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, 73 Jingshi Road, Jinan 250061 (China). E-mail: zh_zhang@sdu.edu.cn
Publication Date:
OSTI Identifier:
20833196
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 56; Journal Issue: 3; Other Information: DOI: 10.1016/j.matchar.2005.11.008; PII: S1044-5803(05)00257-3; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM ALLOYS; CALORIMETRY; COPPER ALLOYS; DIFFERENTIAL THERMAL ANALYSIS; IRON ALLOYS; QUENCHING; SILICON ALLOYS; SOLIDIFICATION; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION

Citation Formats

Wang Yan, Zhang Zhonghua, Geng Haoran, and Yang Zhongxi. Formation of the icosahedral quasicrystalline phase in a rapidly solidified Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy. United States: N. p., 2006. Web. doi:10.1016/j.matchar.2005.11.008.
Wang Yan, Zhang Zhonghua, Geng Haoran, & Yang Zhongxi. Formation of the icosahedral quasicrystalline phase in a rapidly solidified Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy. United States. doi:10.1016/j.matchar.2005.11.008.
Wang Yan, Zhang Zhonghua, Geng Haoran, and Yang Zhongxi. Sat . "Formation of the icosahedral quasicrystalline phase in a rapidly solidified Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy". United States. doi:10.1016/j.matchar.2005.11.008.
@article{osti_20833196,
title = {Formation of the icosahedral quasicrystalline phase in a rapidly solidified Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy},
author = {Wang Yan and Zhang Zhonghua and Geng Haoran and Yang Zhongxi},
abstractNote = {In the present work, the effect of wheel speed (quenching rate) on the formation of the quasicrystalline phase in a rapidly solidified Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy has been investigated using X-ray diffraction (XRD), differential thermal analysis (DTA), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results show that rapid solidification has no effect on the phase constitution of the Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy. The addition of Si decreases the stability of the quasicrystalline phase in the conventionally cast Al{sub 52}Cu{sub 25.5}Fe{sub 12.5}Si{sub 1} alloy. The thermal stability of the quasicrystalline phase in the melt-spun alloy depends upon the quenching rate. Moderate-rate rapid solidification can improve the thermal stability of the quasicrystalline phase in the melt-spun alloy. Higher quenching rate instigates the transformation of the quasicrystalline phase into the cubic approximant phase and decreases the stability of the quasicrystalline phase. Furthermore, the transformation temperature decreases with increasing Si addition into the Al{sub (62-x)}Cu{sub 25.5}Fe{sub 12.5}Si{sub x}.},
doi = {10.1016/j.matchar.2005.11.008},
journal = {Materials Characterization},
number = 3,
volume = 56,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}
  • Twinning of the ordered icosahedral quasicrystals has been studied by transmission electron microscopy in a melt-spun Al{sub 75}Cu{sub 12.5}Fe{sub 12.5} alloy. Dendrites of about 10 {micro}m of the icosahedral phase, formed near the wheel side of the melt spun ribbons, have been observed to twin extensively so that a multiple twinning of the grains is observed. Regions of about 1 {micro}m size are twin related through a common five-fold axis to several neighboring regions. The possibility of different orientations of the twins formed by repeated twinning is infinite. Thus the multiple twinning gives rise to a random symmetry for themore » whole grain. Depending on the undercooling achieved across the melt-spun ribbons, several related phases like the decagonal quasicrystal and crystalline monoclinic Al{sub 3}Fe phase in ten-fold multiply twinned form were also observed.« less
  • Aluminium matrix composites containing 15, 30 and 50 vol.% of pulverized Al{sub 62}Cu{sub 25.5}Fe{sub 12.5} (in at.%) melt spun ribbons have been prepared by a vacuum hot pressing (T = 673 K, P = 600 MPa). The microstructure of the initial ribbon and the composites was investigated using X-ray, scanning and transmission electron microscopy. In the as-spun ribbon the quasicrystalline icosahedral phase (i-phase) coexisted with the cubic copper rich β-Al(Cu, Fe) intermetallic compound. The phase composition of Al-Cu-Fe particles changed after consolidation process and the i-phase transformed partially to the ω-Al{sub 70}Cu{sub 20}Fe{sub 10} phase. Additionally, the Θ-Al{sub 2}Cu phasemore » formed at the α(Al)/Al-Cu-Fe particle interfaces. With an increase in volume fraction of the reinforcement the hardness of the composites increased up to HV = 180 for the highest amount of added particles. The ultimate compression strength of the same sample reached the value of 545 MPa. - Highlights: • Al and 15, 30, 50% of pulverized Al{sub 62}Cu{sub 25.5}Fe{sub 12.5} melt spun ribbon were consolidated. • The initial ribbon consisted of the icosahedral i-phase and copper rich β-Al(Cu, Fe). • The i-phase partially transforms to ω-Al{sub 7}Cu{sub 2}Fe phase in all composites. • Increase of microhardness and compressive strength with content of reinforcement • Ultimate compression strength 545 MPa for 50% of added particles.« less
  • Since the observation of an icosahedral phase in Al-Mn, by Shechtman et al., a large number of alloy systems have been identified, where quasicrystals of different types can be obtained after rapid solidification. Of late, the existence of the icosahedral phase in Al[sub 65]Cu[sub 20]Fe[sub 15] has drawn considerable attention, because of the stable nature of the quasicrystalline phase in this alloy, and the fact that these quasicrystals have abnormally low phasonic strains. In the continuous endeavor of finding new alloy compositions, where quasicrystals can be obtained, some guidelines for identifying quasicrystal forming alloys have emerged. One of these guidelinesmore » is the equilibrium crystalline structure of the alloy, presence of icosahedral clusters in the equilibrium crystalline state being a positive indication that a particular alloy may yield quasicrystals on rapid solidification. Similarity of structure of the potential quasicrystal forming alloy, with those alloys, where formation of quasicrystal is already established is another way of arriving at new quasicrystal forming alloys. With this point in view, the alloy Al[sub 23]CuFe[sub 4] was chosen for exploring the possibility of quasicrystal formation on rapid solidification. The equilibrium Al[sub 23]CuFe[sub 4] phase is isostructural, with Al[sub 6]Mn. The microstructure of this alloy has been examined after rapid solidification to ascertain the nature and morphology of the quasicrystalline and crystalline phases.« less
  • Dispersion strengthened Al-8.5% Fe-1.2% V-1.7% Si (8009) alloy containing 40-80 nm diameter dispersoids and exhibiting attractive elevated temperature strengths can be successfully produced by rapid solidification techniques such as Planar Flow Casting (PFC) and Atomized Melt Deposition (AMD). The grain sizes of alloys produced by PFC and AMD are typically O.5 to 1.0 [mu]m. Fine grain sized aluminum alloys have been found to exhibit plastic instabilities such as yield drop, formation of Lueder's bands and positive deviation from Hall-Petch relationship. The stress-strain behavior at room and elevated temperature of the fine grained dispersion strengthened Al-8.5% Fe-1.2% V-1.7% Si alloy producedmore » by PFC and the AMD processes was determined with the objective of delineating the effect of fine grain size on the deformation behavior.« less
  • An Al{sub 65}Cu{sub 20}Fe{sub 15} alloy with the composition of Al-65at%, Cu-20at% and Fe-15at% was prepared from 99.5% pure starting materials. Alloy powders were then produced with a rapidly solidified (RS) device developed by Chen et al. The powders obtained have an average particle size of about 15{mu}m and their cooling rates are estimated to be 10{sup 5}--10{sup 7} K/S. The powders were uniformly sprinkled on to microgrids for observation by transmission electron microscope (H-800 transmission electron microscope equipped with an EDAX SW9100 composition analysis system).