Chinese researchers working on a new superalloy processing technique say their lab results suggest it could be used to build stronger and longer-lasting aircraft engines, according to state media.
Superalloy turbine discs are a core component of aircraft engines and the new technique to cool down the metal alloy faster during manufacturing could significantly improve performance, the official Science and Technology Daily reported on Friday.
It said the new technology had the potential to be used in the engines powering the country’s new sixth-generation fighter jets.
With at least two of these next-gen fighter jets currently under development, there is an urgent need to develop advanced, high-performance aircraft engines – an area where China has lagged behind the West.
To do this, the team at Dalian University of Technology in northeast China tackled a key challenge in the manufacturing process: finding a way to rapidly cool the forged turbine discs made of superalloy.
These discs are among the heaviest and most technically demanding parts of an aircraft engine. Their quality and durability has long been an obstacle for the industry since this determines the engine’s power, efficiency and lifespan.
In an aircraft engine, the turbine discs are the base on which turbine blades are mounted. The discs convert the thermal energy generated by fuel combustion into the rotational force needed to propel the aircraft.
That means the superalloy the discs are made from must be able to withstand extreme temperatures, high pressure and high rotational speeds.
During manufacturing, faster cooling produces smaller and more evenly distributed grains in the metal alloy, which translates to stronger, smoother surfaces and a longer lifespan.
The team in Dalian have developed a technique where multiple high-speed jets of water are used to cool the superalloy in a fine, uniform mist. A computer simulation model is used to optimise placement of the nozzles and jet settings so that the process is precisely controlled, according to the report.
The team said their experiment data showed the cooling speed was 3.75 times faster using this method, and there was a more than a fourfold improvement in crystal grain size distribution.
An ultra-high temperature disc at 1,200 degrees Celsius (2,192 Fahrenheit) cooled down by 673 degrees per minute using this approach, the report said.
“Our cooling speed has met the demands of the new generation of aviation engines,” said Shi Jinhe, a leader of the research team. “We will ... accelerate the application and transformation of the lab results.”
The report did not say how much difference that could make to the performance of turbine discs in terms of temperature resistance and reliability.
Aircraft engines have been a challenge for China. Its fifth-generation fighter jet, the J-20, was plagued for years with engine troubles referred to as “heart disease”.
Development of its WS-15 engine was repeatedly delayed and the fighter jet instead had an inferior engine that was said to have held it back from reaching its full potential, especially when it came to manoeuvrability and stealth capacity at supersonic speed. It was not until July 2023 that the first J-20 prototype fitted with two WS-15 engines began testing – more than 12 years after the J-20’s maiden flight.
Aircraft engine technology has been designated as a key priority in various state strategies as Beijing tries to push the sector to make progress and catch up with other nations. That has seen advances in powder metallurgy processing and the DD6 superalloy, which was used for the turbine discs of the WS-15 engine.
Researchers are said to be developing a DD9 superalloy for China’s next-generation fighter jet engine. That superalloy is reportedly able to withstand temperatures of up to 1,200 degrees, which would put it on par with the XA100 engine made by GE Aerospace for America’s F-35 fighter jet. - SOUTH CHINA MORNING POST
