14 AEROSPACEMANUFACTURING | NOvEMbER 2009
Metallics i Joining
chain as well as disposal at end of life,
and is happening partly as a result of the
EU funded PAMELA project.
Last but not least, Alcan is active in
the field of smart materials, investigating
technologies to enable enhanced
and specific properties beyond the
‘lightweighting’ that is already achievable.
It has developed cost-effective,
functionally graded materials so that
close to the wing box you can have a
totally different behaviour than on top of
the wing.
Alcan has patented a process to insert
Joined up thinking: Alcan’s innovative concept of joining low density aluminium alloy and CFRP
a sensor fibre as an active part of a
plate or extruded part, providing the
possibility of detection alongside the
new technologies and new design performance at two levels, at macro and structural properties of the material and
solutions to metallic structures. nano scales. is working with universities to see where
In a classic three-way relationship, this In tests with these new alloys, some this innovation can be taken. Structural
eternal triangle of advanced engineering 30% improvement in corrosion potential health monitoring is an expanding field
between material, process and product is seen compared with standard 7000 in aerostructures, but for aluminium
design has provided the inspiration series alloys. This eases an already tight components it is not as necessary as the
for Alcan’s actions. It is impossible situation in joint design but does not material is well understood and it is well
to take action in one of these factors eliminate the corrosion problem for known how cracks propagate. There is,
without the others being affected, or to designers and aircraft operators. however, the possibility to extract other
optimise one in isolation. Nowhere is information from structures such as
this more evident than at the interface Three pillars of development local stresses or temperatures and this
between aluminium and carbon in hybrid In addition to alloy development, Alcan creates the possibility of reacting to
composite/metallic structures. has identified three other pillars for this information to manage effects like
The electrochemistry of the the development of its ability to satisfy aeroelasticity.
aluminium/carbon pairing counts against customer demands: integrated solutions, With all this activity going on in
it in hybrid structures: the difference sustainability and smart materials. developing technical and business
in electronegativity between these two In addressing integrated solutions, solutions, it is unlikely that any future
elements is sufficient to create a battery it has simultaneously tackled alloy and aircraft will fly without a significant
or, in the presence of an electrolyte, design and joining development with the fraction of aluminium on board. ❙
accelerated galvanic corrosion. Perhaps aim of making aluminium live in a hybrid www.alcanaerospace.com
counter-intuitively, the addition of environment. Alcan has been investing a
lithium as an alloying element, itself lot of effort in this field, characterised by
well known as an electrochemically the establishment last year of a research
active material, provides lower chair in multi-materials and interfaces
corrosion potential through the at the Ecole Polytechnique Fédérale de
formation of nanoscale dendritic Lausanne. This is significant, as there are
microstructures. Because of these now two professors working on this issue
specific nanoparticulates, corrosion is of the interface between materials.
mainly due to pitting and is intergranular Regarding sustainability, Alcan’s model
in nature. When considering Al-Li is to offer a closed loop solution to the
alloys, Alcan is creating dendrites within customer by designing metals and alloys
the microstructure that are actually that can be recycled. Here is where
nanomaterials, and by looking at these aluminium has a specific advantage over
alloys in a wider context than just carbon fibre in its inherent recyclability.
corrosion it has been possible to alter This means actions alongside the value
Give me an I: An extruded product for the floor beams
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