Researchers from Japan’s Kyoto University have found molybdenum silicide-based composites improve the efficiency of turbine blades.
Installed in many of today's natural-gas-fueled power plants, gas turbines serve as engines to generate electricity and usually operate in temperatures in excess of 1,600°C, said the researchers. Nickel-based turbine blades tend to melt at temperatures beyond 1,400°C, and therefore require an air-cooling feature to allow them to function.
To develop materials with higher melting temperatures, Kyoto University's material scientists examined the properties of various molybdenum silicide compositions by including and excluding extra ternary elements.
The team fabricated molybdenum silicide-based materials using a method known as directional solidification, which sees molten metal progressively solidify in a certain direction.
The team discovered that by controlling the solidification rate of the molybdenum silicide-based composite during fabrication and altering the amount of the ternary element added to the composite, a homogeneous material could be formed.
This homogeneous material under the uniaxial compression above 1,000°C starts deforming plastically and its high-temperature strength increases through microstructure refinement.
Scientists identified that adding tantalum proved more effective as it improves materials strength even at 1,400°C temperature.
Alloys developed by the Kyoto University team were found to be better even in high-temperatures in comparison to the nickel-based super-alloys, as well as recently developed ultrahigh-temperature structural materials.