ALUMINUM: NEW ALLOYS AND HEAT TREATMENT
Synthesis of an Al–Mn-Based Alloy Containing In Situ-Formed
Quasicrystals and Evaluation of Its Mechanical and Corrosion
1.—Department of Materials and Metallurgy, Faculty of Natural Sciences and Engineering,
University of Ljubljana, As
eva cesta 12, 1000 Ljubljana, Slovenia. 2.—Department for
Nanostructured Materials, Joz
ef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia.
3.—Faculty of Metallurgy and Technology, University of Montenegro, Cetinjski put b.b,
81000 Podgorica, Montenegro. 4.—e-mail: firstname.lastname@example.org
An Al–Mn alloy with additions of copper, magnesium, and silicon was pre-
pared and cast into a copper mold. It contains in situ-formed icosahedral
quasicrystals (iQCs), as conﬁrmed by electron backscatter diffraction. The aim
of this work is to present the mechanical and corrosion properties of this alloy
and compare its properties with some conventional commercial materials. The
compressive strength and compressive yield strength were 751 MPa and
377 MPa, while the compressive fracture strain was 19%. It was observed that
intensive shearing caused the ﬁnal fracture of the specimens and the frac-
tured iQC dendrites still showed cohesion with the a-Al matrix. The polar-
ization resistance and corrosion rate of the artiﬁcially aged alloy were 7.30 kX
and 1.2 lm/year. The evaluated properties are comparable to conventional,
discontinuously reinforced aluminum metal-matrix composites and structural
wrought aluminum alloys.
The discovery of quasicrystals (QCs) by Shecht-
man et al.
created a revolution in crystallography.
Diffraction patterns of these QCs indicated a non-
periodic array of peaks and the presence of icosa-
hedral symmetry, which is forbidden in traditional
These ﬁrst icosahedral QCs (iQCs)
were thermodynamically metastable, but soon,
stable QCs were also discovered.
Nonstick coatings and maraging steel are familiar
applications of QCs.
Another possible application
of iQCs could be mechanical reinforcement of con-
ventional metallic materials. The high symmetry and
quasiperiodicity of the iQC phase both contribute to
forming epitaxy at all the interfaces in the bulk.
There have been several reports of incorporation of
stable iQCs into a metal or alloy matrix.
sive research work has already been done on devel-
opment of magnesium alloys reinforced with iQC
In several cases, an ex situ fabrication
process was used,
where iQC particles are
introduced into the melt or a solid matrix alloy. In
situ formation of iQCs, on the other hand, means that
iQC particles form in a liquid melt as a primary phase
or as a eutectic structure. The interface in such a
production process is usually free of defects that often
appear in the case of an ex situ fabrication process.
Alloys comprising in situ-formed iQCs usually
cerium and cerium-rich mis-
However, these elements can decrease
the cooling rate needed for formation of
metastable iQCs in the Al–Mn-based alloy system.
Silicon and copper are also elements with a similar
It was also observed that dendritically
shaped primary iQC particles form in an Al–Mn
alloy containing copper, silicon, and magnesium.
In the work presented herein, an alloy with a
modiﬁed composition containing less silicon, copper,
and magnesium was prepared. The aim is to present
the microstructure and mechanical and corrosion
properties of such an iQC-containing alloy and
compare its properties with some conventional
2018 The Minerals, Metals & Materials Society