Single Crystal Blade Technology.
                     Single Crystal 
Blade 
Technology
Introduction
The Defence Research and 
Development Organisation 
(DRDO) has developed single 
crystal blades technology for 
helicopters and has supplied 60 
of these blades to Hindustan 
Aeronautics Limited (HAL) as part 
of their indigenous helicopter 
development programme for 
engine application.
Source: www.indiatoday.in
Single crystal high-
pressure turbine
This is part of a programme taken 
up by Defence Metallurgical 
Research Laboratory (DMRL) to 
develop five sets of single crystal 
high-pressure turbine (HPT) 
blades using a nickel-based 
superalloy.
Source: www.indiatoday.in
Strategic and 
defense 
applications
Helicopters used in strategic and 
defence applications need 
compact and powerful aero 
engines for operating in extreme 
conditions. 
Source: www.indiatoday.in
Nickel-based 
superalloys
To achieve this, state-of-the-art 
single crystal blades with 
complex shape and geometry, 
manufactured out of nickel-based 
superalloys capable of 
withstanding high temperatures 
of operation are used. 
Source: www.indiatoday.in
Vacuum investment 
casting process
Complete vacuum investment 
casting process to realise the 
blades, including die design, wax 
pattering, ceramic moulding, the 
actual casting of components 
non-destructive evaluation (NDE), 
heat treatment and dimensional 
measurement has been 
established at DMRL
Source: www.indiatoday.in
Ceramic 
composition
Special ceramic composition had 
to be formulated for making 
strong ceramic moulds that can 
withstand metallostatic pressure 
of liquid CMSX-4 alloy at 1500°C 
and above during casting 
operation, DMRL said.
Source: www.indiatoday.in
Challenges
The challenge of maintaining the 
required temperature gradient has 
also been overcome by optimizing 
the casting parameters, it said, 
adding that a multi-step vacuum 
heat treatment schedule for 
complex CMSX-4 superalloy to 
achieve the required 
microstructure and mechanical 
properties has also been 
established.
Source: www.indiatoday.in
Non-destructive 
Evaluation
Further, a stringent Non-
destructive Evaluation (NDE) 
method for the blades along with 
the technique for determining 
their crystallographic orientations 
has been developed.
Source: www.indiatoday.in
Applications
Components for gas turbine 
engines of aircraft for high 
efficiency, high thrust and low 
specific fuel consumption.
Source: www.drdo.gov.in
Salient Features
• Directionally solidified turbine 
blades and vanes are columnar 
grained hollow castings with thin-
walled aero foils between two 
shrouds
• Single crystal turbine blades and 
vanes are produced by using 
orthogonal grain selector from 
advanced Ni‐base super alloys
Source: www.drdo.gov.in