Exploring additive manufacturing of materials for aerospace industry

Every percentage of weight reduction in the aviation industry counts, as demonstrated by the Boeing 787 where 20% weight reduction led to an approximate 12% boost in fuel efficiency. With the United Nations International Civil Aviation Organisation aiming to cut aviation emissions by 50% by 2050, further reductions are critical. This is where the LattiGRAM research project led by the University of Malta’s Department of Metallurgy and Materials Engineering focused.

LattiGRAM explores additive manufacturing (i.e. 3D printing) of Ti-6Al-4V; a titanium alloy, to make lattices. Lattices are porous structures designed to replace solid components, reducing mass while retaining the essential mechanical performance, ideal for aviation applications.

Among the many possible designs, gyroids have shown great promise. Gyroids are bio-inspired, featuring wave-like surfaces that maximise mechanical performance while minimising mass. Found in butterfly wings and marine animal skeletons, gyroids offer exceptional strength while using minimal material. Traditional manufacturing methods, however, struggle to produce these complex shapes.

Additive manufacturing builds parts in a layer-by-layer from 3D model data, making it ideal to generate lattices. One approach is powder bed fusion, where thermal energy from a laser or electron beam selectively melts regions of a powder bed. This process has a high feature resolution, enabling the production of such fine structures.

This concluding research project focused on comparing two powder bed fusion techniques: laser powder bed fusion (L-PBF) and electron beam powder bed fusion (EB-PBF) to produce gyroid lattices.

EB-PBF samples exhibit a higher density due to residual powder trapped within the small pores of the structures which is very difficult to remove but also served to enhance strength and stiffness; making them ideal for high-load applications. L-PBF, on the other hand, produced lattices that more closely matched the designed porosity values, offering superior precision and control.

These findings highlight a trade-off between strength and manufacturing accuracy, offering engineers greater flexibility when designing aircraft components. By leveraging advanced lattice designs, there is the potential to reduce the structural weight by 20 to 30%.

Project LattiGRAM is financed by Xjenza Malta for and on behalf of the Foundation for Science and Technology, through the FUSION: R&I Research Excellence Programme.

Kersty Jo Zammit is an MSc mechanical engineering student investigating Ti-6Al-4V lattices using additive manufacturing.

Bonnie Attard is an academic at the Institute of Engineering and Transport at MCAST focusing on material behaviour in additive manufacturing.

Glenn Cassar is an academic at the Department of Metallurgy and Materials Engineering at the University of Malta, specialising in material performance improvement following bulk and surface processing.

Photo of the week

Photo: Linden Gledhill, https://www.lindengledhill.com/butterfly-scales/s3l0r7roidntihiudaceum8j0iqepf

This is a macro photograph of a butterfly wing. The multilayer thin-film structures that make up a butterfly wing appear iridescent in sunlight. This is due to the light interacting with the repeating pattern in the thin-film structure, resulting in changes in reflected colour. These microscopic thin-film structures also help the insect maintain its body temperature and increase the wing’s resistance to bending. 

Sound Bites

•         Bones are stronger than steel by weight – despite their lightweight structure, bones are incredibly strong. They can withstand more compression than steel, thanks to their hierarchical internal structure. This strength allows bones to support the body’s weight and endure significant physical stress without breaking easily.

•         Coral skeletons have been used in medical research – coral’s porous calcium carbonate structure is similar to human bone, making it useful for bone grafts and implants. Scientists have used coral skeletons as scaffolding for bone regeneration, demonstrating how marine biology can contribute to medical advancements in treating injuries and bone diseases.

For more soundbites, listen to Radio Mocha www.fb.com/Radio MochaMalta/.

DID YOU KNOW?

•         A day on Venus is longer than a year on Venus: Venus takes about 243 Earth days to rotate once on its axis, but only 225 Earth days to orbit the sun, making its day longer than its year.

•         Astronauts grow taller in space. Without Earth’s gravity compressing their spines, astronauts can grow up to 5cm taller while in orbit.

•         Gyroids are not only found in nature but are also the quirky objects in the popular game series Animal Crossing.

•         The Boeing 747’s wingspan (64 metres) is longer than the distance travelled in the Wright Brothers’ first flight (36 metres).

For more trivia, see: www.um.edu.mt/think.