Indian scientists have, for the first time, repaired aero-engine components through emerging additive manufacturing or 3D printing technique called ‘Directed Energy Deposition’ process that can significantly reduce repair costs and overhaul time.

The scientists indigenously prepared the powders suitable for the additive manufacturing process.

Ni-based superalloys are widely used in aero-engine components, but despite having exceptional properties, are prone to damage due to extreme operational conditions. Manufacturing defects during the casting or machining process are another major cause of rejection, and tons of such unused components are scrapped due to minor defects.

“A team of scientists from the International Advanced Research Centre for Powder Metallurgy & New Materials (ARCI) indigenously developed powders suitable for additive manufacturing using inert gas atomiser available at the ARCI by melting unused scrap material. Utilising this, the ARCI is developing the Laser-DED process for the repair of aero-engine components made of Ni-based superalloy,” a release said here.

The team of an ARCI, an autonomous R&D Centre of Department of Science and Technology, developed a technology to refurbish pinion housing assembly — a critical component in helicopters used for power transmission to the main fan — by machining out the damaged layer and rebuilding it using laser cladding process followed by final machining. Laser cladding is the same as Laser-DED; in general, for two-dimensional deposition (surface coating), the term laser cladding is used, and for the manufacture of three-dimensional parts, the term laser-DED is used. A patent has been filed for the same.

A post-clad heat treatment method was also designed to minimise microstructural inhomogeneity and ensure minimal substrate properties variation. These laser-clad repaired prototypes were found to be free from distortion and exhibited excellent performance. The team has also developed repair and refurbishment technologies for other industrial sectors, such as refurbishing diesel engine cylinder heads made of grey cast iron and refurbishing shafts used in refineries.

This work has been published in the journal ‘Transactions of The Indian Institute of Metals’, the release said.

The impact of repair and refurbishment technology developed by the ARCI can, therefore, be best realised in the aerospace sector due to expensive materials, manufacturing costs, and stringent quality checks, the release added.