High-strength aluminium (Al) alloys are extensively used in aerospace, textile, and automotive applications owing to their low density and high specific strength. Aerospace components made out of Al alloys include landing gear, wing spar, which is the main structural part of the wing, fuselage (main body of an aircraft), aircraft skins or outer surface and pressure cabins. These parts often need resistance against wear, corrosion damages, and enhanced fatigue life. The widely used technique for Al alloys to improve corrosion resistance called hard anodizing (HA) process is an electrolyte-based coating deposition. It involves sulphuric/oxalic based electrolytes, which emits not only toxic fumes but are also hazardous to handle during processing.

In order to cater to the growing demand for cleaner industrial processes, an environmental-friendly process called micro-arc oxidation (MAO) has been developed at 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. The process which involves an alkaline electrolyte is capable of providing better wear and corrosion resistance compared to the HA process.

MAO is a high-voltage driven anodic-oxidation process, which through an electrochemical method, produces an oxide film on a metallic substrates. ARCI team has further designed and developed a duplex treatment of shot peening (process used to modify the mechanical properties of metals and alloys) followed by MAO coating deposition. Systematic investigations conducted at ARCI have shown that the duplex treatment has led to the remarkable enhancement in aerospace Al alloys’ fatigue life while retaining the outstanding corrosion and wear resistance of MAO coating. The efficacy of duplex treatment has been validated for different Al alloys and extended to impart superior corrosion fatigue life. This work has been recently published in the ‘International Journal of Fatigue’.

The MAO process developed at ARCI has been patented in India and abroad. The team at ARCI has mastered the design and development of MAO systems of a lab (20 kVA), bench (75 kVA), and industrial (up to 500 kVA) scales to enable translating the technology from the R&D level to commercial production. As a logical extension, the custom-built technology systems were transferred to various industries and academic institutes in India. To cater to the aerospace segment, 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.

The process with necessary modifications can be used for wear, corrosion, thermal, and fatigue and corrosion-fatigue life enhancement of a variety of components made out of Al, Mg, Ti, Zr, and their alloys.

The MICU has two sets of Defibrillators, Multipara Monitors, Ventilator, Oxygen Support as well as Infusion and Syringe Pumps. It also has a suction system to clear secretions in the mouth or airway of the patient. The system can be operated on aircraft power supply and also has a battery back up of four hours. The equipment can be installed in two-three hours to convert the aircraft into an air ambulance. This is the first of eight MICU sets to be delivered by HAL to Indian Navy.

To meet the bulk production requirements, DMRL technology was transferred to M/s MIDHANI through a licensing agreement for technology transfer (LAToT). Using the isothermal forge press facility available at DMRL, Hyderabad, bulk quantity (200 numbers) of HPC disc forgings pertaining to various compressor stages have been jointly (DMRL & MIDHANI) produced and successfully supplied to HAL (E), Bengaluru for fitment in to Adour Engine that powers the Jaguar/Hawk Aircrafts.

In India, the Adour engine is overhauled by HAL (E), Bengaluru under a licensed manufacturing agreement with OEM. Like in any aeroengine, the HPC Drum assembly has to be replaced after a specified number of operations or in case of damage. The annual requirements of these high value HPC discs are quite large, warranting indigenisation. HPC drum is a highly stressed sub-assembly and is also subjected to low cycle fatigue and creep at elevated temperature. The raw materials and forgings for HPC drum are required to be of the highest quality which can meet the specified combination of static and dynamic mechanical properties.

DMRL developed this forging technology by integrating various science and knowledge-based tools. The methodology adopted by DMRL is generic in nature and can be tuned to develop other similar aeroengine components.  The compressor discs produced using this methodology met all the requirements stipulated by the airworthiness agencies for the desired application. Accordingly, the technology was type certified and letter of technical approval (LoTA) was accorded. Based on the exhaustive component level and performance evaluation test results, HAL (E) and Indian Air Force cleared the components for engine fitment. Apart from DMRL and HAL (E), various agencies such as MIDHANI, CEMILAC and DGAQA worked in unison to establish this crucial technology.

Raksha Mantri Shri Rajnath Singh has congratulated the scientists of DRDO, Industry and all other agencies involved in the development of this critical Aero Engine related technology.

Secretary Department of Defence R&D and Chairman DRDO Dr G Satheesh Reddy expressed his satisfaction on achieving this crucial milestone and congratulated the teams involved.

The hypersonic cruise vehicle was launched using a proven solid rocket motor, which took it to an altitude of 30 kilometres (km), where the aerodynamic heat shields were separated at hypersonic Mach number. The cruise vehicle separated from the launch vehicle and the air intake opened as planned. The hypersonic combustion sustained and the cruise vehicle continued on its desired flight path at a velocity of six times the speed of sound i.e., nearly 02 km/second for more than 20 seconds. The critical events like fuel injection and auto ignition of scramjet demonstrated technological maturity. The scramjet engine performed in a text book manner.

The parameters of launch and cruise vehicle, including scramjet engine was monitored by multiple tracking radars, electro-optical systems and Telemetry Stations. The scramjet engine worked at high dynamic pressure and at very high temperature. A Ship was also deployed in the Bay of Bengal to monitor the performance during the cruise phase of hypersonic vehicle. All the performance parameters have indicated a resounding success of the mission.

With this successful demonstration, many critical technologies such as aerodynamic configuration for hypersonic manoeuvers, use of scramjet propulsion for ignition and sustained combustion at hypersonic flow, thermo-structural characterisation of high temperature materials, separation mechanism at hypersonic velocities etc. were proven.

Raksha Mantri Shri Rajnath Singh congratulated DRDO on this landmark achievement towards realising Prime Minister Narendra Modi’s vision of Atmanirbhar Bharat. He also spoke to the scientists associated with the project and congratulated them on this great achievement. India is proud of them, he added.

Secretary Department of Defence R&D and Chairman DRDO Dr G Satheesh Reddy congratulated all the Scientists, Researchers and other personnel related with HSTDV mission for their resolute and unwavering efforts towards strengthening Nation’s defence capabilities. On this successful demonstration, the country enters into the hypersonic regime paving way for advanced hypersonic Vehicles.

The missile intercepted the target with text book precision. The launch met all the test objectives by performing high maneuvers during the trajectory. The performance of the Command and Control system, onboard avionics and aerodynamic configuration of the missile was successfully validated during the trial.  During the test launch, entire flight path of the missile was monitored and the flight data was captured by various Range instruments such as Radar, EOTS and Telemetry systems deployed by ITR, Chandipur. The Multi Function Radar was tested for its capability of integration with the system.

The Akash-NG system has been developed with better deployability compared to other similar systems with canisterized launcher and much smaller ground system footprint. The test launch was carried out by a combined team of DRDO, BDL & BEL in the presence of the representatives of Indian Airforce.

Raksha Mantri Shri Rajnath Singh congratulated the scientists from DRDO, BEL and team from Indian Air Force for this achievement. Secretary DD R&D and Chairman DRDO Dr. G Satheesh Reddy  congratulated the team for the successful flight trial of Akash NG Missile.