Indian scientists develop environment-friendly process amplifies exhaust life of aluminium alloy utilized in aerospace parts

The scientists of India have developed an environment-friendly procedure that can deliver excellent corrosion resistance to high-strength aluminium alloys exhaustively used in aerospace, textile, and automotive applications.

The process, labelled micro-arc oxidation (MAO), implies an electrochemical method for the production of an oxide film on the metallic substrate. The electrolyte of the film is alkaline and competent in delivering better wear and corrosion resistance emulating to the existing process.

High-strength aluminium alloys are rigorously used in aerospace, textile, and automotive applications due to their low density and high specific strength. Aerospace parts manufactured from aluminium alloys comprise landing gear, the main structural part of the wing, fuselage, aircraft skins and pressure cabins.

Now, these components require resistance against wear and corrosion damages in addition to intensified fatigue life. The universally used technique for aluminium alloys to upgrade corrosion resistance at present is called hard anodizing. It involves sulphuric and oxalic-based electrolytes which discharge not only toxic fumes but are also hazardous to handle during processing.

MAO was developed at the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), an autonomous R&D Centre of the Department of Science and Technology, Govt. of India, to cater towards the rise in demand for cleaner industrial processes.

While to serve the aerospace industry, extensive research has been carried out at ARCI, and the high-cycle fatigue life of aerospace Al alloys under plain and simultaneous corrosion environments could be significantly improved.

ARCI team has further designed and developed a duplex treatment of ‘shot peening’, a process used to modify the mechanical properties of metals and alloys, followed by coating deposition.

As per the statement released on 7th June 2021 by the Ministry of Science and Technology: “Systematic investigations conducted at ARCI have shown that the duplex treatment has led to the remarkable enhancement in aerospace aluminium alloys' fatigue life while retaining the outstanding corrosion and wear resistance of MAO coating.”

“The efficacy of duplex treatment has been validated for different aluminium alloys and extended to impart superior corrosion fatigue life. This work has been recently published in the International Journal of Fatigue,” the ministry added.

The MAO process developed at ARCI has been patented in India and abroad, while the technology transfer is all set for commercial production. The process with requisite refinement can be used for wear, corrosion, thermal, and fatigue and corrosion-fatigue life enhancement of a variety of components made out of aluminium, magnesium, titanium and zirconium.