DRDO develops single crystal blades for helicopter engine application
India is the fifth country in the world to develop such a cutting-edge technology
In a significant technological development, DRDO has designed and developed single crystal blades that would give helicopters, used in strategic and defence application, enough power to fly even in extreme conditions.
According to the Ministry of Defence, very few countries in the world such as the US, the UK, France and Russia have the capability to design and manufacture single crystal (SX) components.
Developed by DRDO’s Defence Metallurgical Research Laboratory (DMRL), the state-of-the-art technology with complex shape and geometry is manufactured out of Nickel based super alloys capable of withstanding high temperatures.
The DMRL has supplied 60 of these blades to Hindustan Aeronautics Limited (HAL) as part of their indigenous helicopter development program for helicopter engine application.
The DMRL undertook this task based on its expertise gained during the development of such a technology for an aero-engine project earlier.
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 1500°C 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 solutionizing heat treatment schedule for complex CMSX-4 super alloy 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.
Raksha Mantri Rajnath Singh has congratulated DRDO, HAL and the industry involved in the development of critical technology.
Secretary Department of Defence R&D and Chairman DRDO Dr G Satheesh Reddy congratulated and appreciated the efforts involved in the indigenous development of this vital technology.