CA1-20
Nanoscale cell parameters of the tetragonal -CUAL2 phase
H. Bedboudi1*, A. Bourbia2,* and M. Draissia*
1-École Nationale Supérieure de L'Enseignement Technologique de Skikda
2-EPST ANNABA
*LM2S, Physics Department, Faculty of Science, Badji-Mokhtar University, PB 12
Annaba, 23000 Algeria.
Email: bedboudihayette@yahoo.fr
The purpose of this work is to determine the cell parameters of the
tetragonal -CuAl2 phase formed in the Al-Cu based alloys. The study
focuses on the effect of Zn on the Fcc Al solid solution extension in
the ternary Al-Cu-Zn alloys compared to the binary Al-Zn alloys.
Some binary Al-Xwt.%Zn (X= 4, 16, 40 and 50) and Al-Xwt.%Cu25wt.%Zn (X= 2, 8, 20 and 25) alloys samples were rapidly solidified
under vacuum by the high-frequency (HF) melting process from cold
compacted Al-Zn and Al-Cu-Zn targets mixtures of high purity (over
99%) alloying metals Al, Cu and Zn powders. Microstructure
characteristic parameters of the as-melted (hf) Al-Zn and Al-Cu-Zn
alloys were investigated by means of X-ray diffraction analyses and
optical microscopy observations. It was found that the microstructures
of the (hf) Al-Zn and Al-Cu-Zn alloys were homogeneous with
refined grains. The (hf) Al-Zn alloys were single-phase
microstructures of the Fcc αAl(Zn) solid solution with full solubility
of the Hcp Zn in the Fcc Al matrix and this is due to grain size
difference between the solvent Al and the solute Zn atoms.
Microstructures of the ternary (hf) Al-Cu-Zn alloys were indexed to
be two phases, the expected tetragonal θ-CuAl2 phase in equilibrium
with the solid solution Fcc αAl(Cu,Zn) phase for the Al-Cu-Zn alloys
of compositions over 4wt.% to 25wt.%. The nanoscale cell parameters
for the detected expected body-centred -CuAl2 phase in the as-melted
(hf) Al-Cu-Zn alloys have been deduced to be around 0.6069(8) nm
for a=b and 0.4953(5) nm for c with the ratio of 0.8160 for c/a in good
agreement with that of literature.
Key words: Aluminium alloys, hf melting, Microstructure,
Intermetallic compounds, Nanoscale parameters.
Matériaux 2015
[1] JCPDS-ICDD 1997 card 25-0012.
[2] M. Draissia, M.Y. Debili, Central European Journal of Physics CEJP 3(3)
Springer, (2005), p. 395.
[3] M. Draissia, M.Y. Debili, J. of Crystal Growth 270(1-2), (2004), p. 250.
[4] H. Bedboudi, M. Draissia, A. Bourbia, S. Boulekhssaim, M.Y. Debili. Materiaux
& Techniques V. 98 N. 3 (2010), p. 219.
Matériaux 2015