Scientists have researched a technology that could reduce the cost of producing high-strength materials for aircraft construction.

Scientists have discovered a way to produce an alloy with exceptional strength while simultaneously making its production cost-effective. To achieve this, they developed an electromagnetic field casting technology that allows them to produce ingots from an experimental aluminum alloy with zinc and magnesium. The development is registered under the trademark Elmacast™. This alloy could be used, for example, in aircraft manufacturing. The new technology will significantly simplify and reduce the required ingots producing cost.

The research project was developed by specialists from Siberian Federal University (SFU) and their colleagues from the National Research University of Science and Technology (MISiS). SFU scientists were responsible for developing the technology and its theoretical description, while MISiS researchers performed the phase analysis of the ingots and the products mechanical properties.

Aluminum ranks first among all non-ferrous metals in terms of production and consumption. However, unique aluminum products cannot be produced using traditional casting methods—where alloys are poured into molds. Therefore, new, efficient, and cost-effective methods must be developed.

"Aluminum faces a challenge related to the need to significantly improve the strength properties of aluminum alloy products—this is critical for areas such as aircraft manufacturing, construction, and additive manufacturing technologies. Alloys based on the Al-Zn-Mg-Cu system, additionally alloyed with nickel, cobalt, and iron, possess suitable properties," said Eduard Winter, a co-author of the study and a scientist at the SFU Polytechnic Institute.

As experts note, products made from these alloys cannot be produced using traditional casting methods. Powder metallurgy methods are required, which, while providing unique product characteristics, are associated with high costs, stringent safety requirements, complex process chain management, and low productivity.

By conducting numerical modeling, the scientists determined the set of technical and technological parameters of the foundry equipment required to produce the required quality cast billets. In subsequent experiments, they produced aluminum ingots from alloys with high strength properties.

Electromagnetic field casting (EMC), studied jointly by scientists and experts from the Research and Production Center of Magnetic Hydrodynamics (Krasnoyarsk), provides cast billets cooling rates comparable to those achieved with powder metallurgy. This allows for the production of cast products from complex multicomponent aluminum alloys. At the same time, compared to powder metallurgy methods, the new technology requires a simplified equipment layout, is less expensive, and is significantly more productive.

According to the researchers, the process of casting in an electromagnetic field involves phenomena such as electromagnetism, heat and mass transfer, metal phase transitions (crystallization), and the dynamics of the interphase boundary between the levitating melt and the open air. The combination of these factors significantly complicates the theoretical description of the process and requires the use of multidisciplinary numerical analysis methods and tools.

"One of the most challenging tasks we faced in developing this technology and establishing its theoretical foundations was establishing and quantifying these relationships. Understanding how electromagnetic, thermal, and hydrodynamic fields coexist, as well as how microstructures are formed within ingots, allowed us to stabilize casting in a semi-suspended state and create a fully-fledged high-tech industrial complex that meets the modern manufacturing sector's need for high-alloy alloys with enhanced physical and mechanical properties," noted Maxim Khatsayuk, professor in the Department of Electrical Engineering at the SFU Polytechnic Institute.

The scientists also identified a set of technical and technological parameters for casting equipment that can produce cast billets from experimental Al (aluminum)-Zn (zinc)-Mg (magnesium)-Cu (copper) alloys. These billets are characterized by a fine microstructure, with extremely fine grain sizes of no more than 5-15 microns. Furthermore, the particles of iron-containing phases are very small, opening up wide possibilities for further processing. For example, they can be used to produce thin-walled profiles or ultra-thin wire.

The resulting cast billets were subjected to heat and mechanical treatment. As a result, the scientists discovered that the deformation process produces a structure characteristic of composite materials: microparticles of alloying elements are uniformly distributed throughout the aluminum. This structure enables the achievement of high physical and mechanical properties unattainable in products made from mass-produced alloys produced by traditional methods.

The high hardness combination  and the new billets deformation plasticity is a guarantee of high mechanical properties and studied EMC technology potential evidence in relation to experimental alloys.

The scientists' scientific article was published in one of the leading international magazines.

The study was supported by a grant from the Russian Science Foundation (project no. 22-19-00128 “Evolution of the structure of high-strength aluminum alloys of the Al-Zn-Mg (Ni, Fe, Ca) system obtained using electromagnetic casting technology”).

SourcePhoto: MISiS