Aluminum samples: scientists will create high-strength parts for airplanes from scrap

Russian scientists have developed a new generation alloy that will find application in aviation. It is a compound that, in addition to aluminum, includes iron, calcium and copper. Due to this, the industry will be able to produce parts from scrap, which will reduce the cost of finished products. The resulting material can be used for the manufacture of cladding panels, as well as for 3D printing of complex parts. It is also promising for use in mechanical engineering and other high-tech industries, experts say.

How scientists got a more durable material

Scientists from the University of Science and Technology MISIS have created an alloy for the aircraft of the future. It is a four—component compound that, in addition to aluminum, a traditional aviation metal, includes iron, calcium and copper.

The special feature of the alloy's internal structure is its neat crystal lattice, in which individual atoms are tightly packed together. This makes it possible to create workpieces without cracks and other defects. In addition, it suppresses the harmful effects of iron impurities. Instead of spoiling the material, making it brittle, this element combines with other additives to form special durable particles that, on the contrary, strengthen the entire alloy.

Photo: NUST MISIS Press service

As a result, the new material is easily rolled into sheets, does not crack at high temperatures and becomes very hard after special treatment.

— Iron is an unavoidable component in aluminum alloys. It can enter it both from primary aluminum and during the manufacturing process of recycling secondary raw materials. When iron appears in an alloy, it forms sharp, needle-like crystals that make the metal brittle. The addition of calcium forms a special eutectic phase (a uniform monotonous mixture. — Izvestia) and provides a stable structure, — explained one of the developers, Doctor of Technical Sciences, senior researcher at the NUST Metalworking Department MISIS Torgom Hakobyan.

Senior Researcher at the NUST MISIS Pressure Metalworking Department, Torgom Hakobyan

Photo: NUST MISIS Press service

As the scientists explained, the resulting material combines lightness and strength, which is typical for aircraft structures. This makes the alloy promising for the manufacture of aircraft skin panels. In addition, the new compound forms a uniform structure without internal stresses and cracks when solidified. Due to this, the development is suitable for use in 3D printing processes of complex parts.

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Aviation alloy of the new generation

According to the developers, the new material can replace AK4-1, a classic heat—resistant deformable alloy that has been used in the aviation and space industries for several decades.

— The main disadvantage of a traditional alloy is the need to use expensive nickel additives in relatively large quantities. The new development uses, as an alternative, the addition of a much cheaper and lighter element, calcium, combined with iron, which is also present in an industrial alloy," explained Torgom Hakobyan.

He added that the strict limitation of the iron concentration in primary aluminum leads to a high cost of the material. This is the so-called high purity aluminum. The proposed formula makes it possible to use high-purity aluminum for the manufacture of aviation products, as well as metal obtained during the processing of scrap and waste.

Nikolay Belov, Chief Researcher at the NUST MISIS Department of Metal Pressure Processing

Photo: NUST MISIS Press service

At the same time, as one of the developers, Nikolai Belov, Doctor of Technical Sciences, chief Researcher at the NUST MISIS Department of Metalworking, noted, the homogeneous structure of the new alloy prevents the appearance of cracks during 3D printing of large parts.

— The new material contains a fairly large amount of a component called "eutectic" in its structure, it may be promising for 3D printing technologies based on the appearance of a liquid phase. We expect that the fine structure of the eutectic formed during 3D printing will allow us to achieve both high processability of the material in the manufacture of products using this method, and high mechanical characteristics (strength, wear resistance, etc.) of the finished product," the specialist explained.

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Introduction to production

When implemented in industrial enterprises, the development will significantly reduce the cost of production, experts say. In addition to aviation, the proposed material is also promising in mechanical engineering and other high-tech industries.

In the future, scientists plan to add manganese, silicon and a micro-addition of zirconium to the alloy. This will improve the material's resistance to extreme temperatures and corrosion.

— The proposed development is a new generation alloy, since traditionally calcium in aluminum alloys was considered a harmful impurity, and standards strictly limited its content. However, now scientists are considering the targeted addition of this element as a way to create fundamentally new materials," Alexander Bezrukikh, a leading researcher at the Institute of Non—Ferrous Metals and Materials Science at Siberian Federal University, explained to Izvestia.

Photo: NUST MISIS Press service

In particular, calcium makes it possible to modify the alloy structure, making it more fine-grained and homogeneous. It also allows you to bind harmful impurities (for example, iron too), which prevents the formation of brittle particles and improves plasticity, the specialist noted.

Currently, the production of aircraft structures from scrap is not widespread, but the development of scientists may allow us to take a step in this direction. The inclusion of scrap in the production cycle will reduce the cost of finished products.

— The problem of fragility, especially for aerospace materials, remains relevant. At the same time, increasing crack resistance should be inextricably linked to maintaining or improving other key properties of the material, such as strength," said Nikolai Turbin, head of the Laboratory for Modeling Composite Materials and Structures at the advanced Engineering School of MAI.

Photo: NUST MISIS Press service

At the same time, it is necessary to understand that in order to allow the material to be used in critical structures, the so-called special qualifications are mandatory, he stressed. It establishes the fundamental suitability of the candidate material for operation in extreme operating conditions - under the influence of specified temperatures, humidity and other factors.

At the same time, the development and implementation of a new material is always more expensive than the design of the structure itself. This is due to the need to conduct a huge complex of tests, refine technological processes and create a complete package of design and technological documentation, he added.