New Delhi: India’s defence research and development agency today said it has developed Single Crystal Blades technology and supplied 60 of these blades to the nation’s lone aircraft manufacturer for helicopter engine applications.

Defence Research and Development Organisation (DRDO) said in a statement here that this supply was part of Hindustan Aeronautics Limited‘s (HAL’s) indigenous helicopter development programme.

Defence Metallurgical Research Laboratory (DMRL), a premium laboratory of DRDO, has taken up a programme to develop five sets (300 in number) of single crystal high pressure turbine (HPT) blades using a nickel-based super alloy. The supply of remaining four sets will be completed in due course, the statement said.

Helicopters used in strategic and defence applications need compact and powerful aero-engines for their reliable operation at extreme conditions. To achieve this, state-of-the-art Single Crystal Blades, having complex shape and geometry, manufactured out of Nickel-based superalloys capable of withstanding high temperatures of operation are used.

Very few countries in the world such as the United States of America, the United Kingdom, France and Russia have the capability to design and manufacture such Single Crystal (SX) components.

DMRL undertook this task based on its expertise gained during the development of such a technology for an aero-engine project. Complete vacuum investment casting process to realise the blades, including die design, wax pattering, ceramic moulding, actual casting of components non-destructive evaluation (NDE), heat treatment and dimensional measurement, has been established at DMRL.

Special ceramic composition had to be formulated for making strong ceramic moulds which can withstand metallostatic pressure of liquid CMSX-4 alloy at 1,500-degree Celsius and above during casting operation.

The challenge of maintaining the required temperature gradient has also been overcome by optimising the casting parameters. A multi-step vacuum solutionising heat treatment schedule for complex CMSX-4 superalloy to achieve the required microstructure and mechanical properties has also been established.

Further, a stringent non-destructive evaluation (NDE) methodology for the blades along with the technique for determining their crystallographic orientations has been developed.

Minister of Defence Rajnath Singh has congratulated DRDO, HAL and the industry involved in the development of critical technology. DRDO Chairman and Department of Defence Research and Development Secretary Dr G. Satheesh Reddy congratulated and appreciated the efforts involved in the indigenous development of this vital technology.

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